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Milk contains a number of bone-beneficial nutrients. However, milk, due to the D-galactose content, might have unfavorable effects on bone health. A meta-analysis of randomized controlled trials (RCTs) was performed to clarify the effects of milk supplementation on bone mineral density (BMD), bone turnover markers [N-terminal telopeptide of type I collagen (NTx), C-terminal telopeptide of type 1 collagen (CTx), osteocalcin, bone alkaline phosphatase (BALP), and procollagen type 1 N-propeptide (P1NP)], and hormonal indices related to bone metabolism [parathyroid hormone (PTH), 25-hydroxyvitamin D [25(OH)D], and insulin-like growth factor 1 (IGF-1)] in adults. The PubMed and Web of Science databases were searched. A random-effects model was used to estimate the pooled effect sizes. A total of 20 RCTs were included. The trial duration ranged from 1 mo to 36 mo. Milk supplementation resulted in a small but significant increase in BMD at the hip (+0.004 g/cm2; n = 9 RCTs) and lumbar spine (+0.025 g/cm2; n = 7), but did not significantly affect whole-body BMD (n = 3) and femoral neck BMD (n = 7). Milk supplementation reduced the concentrations of P1NP (-5.20 ng/mL; n = 9), CTx (-0.16 ng/mL; n = 9), and NTx (-8.66 nmol bone collagen equivalents/mmol creatinine; n = 3). The concentrations of osteocalcin (n = 9) and BALP (n = 3) were not affected by milk supplementation. Reduced parathyroid hormone PTH (-1.01 pg/mL; n = 13) concentrations and increased IGF-1 (+1.79 nmol/l; n = 4) concentrations were observed with milk supplementation. 25(OH)D (+3.73 ng/mL; n = 11) concentrations were increased with vitamin-D fortified milk supplementation. The addition of milk to the diet may potentially increase the likelihood of preventing bone loss by restoring bone homeostasis through the modulation of the calcium-vitamin D-PTH axis, bone remodeling rate, and growth hormone/IGF-1 axis., (© The Author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition.)

Background: Insulin-like growth factor-1 (IGF-1) has the potential to be used for osteoarthritis (OA) treatment but has not been evaluated in clinics yet owing to toxicity concerns. It suffers from short intra-joint residence time and a lack of cartilage targeting following its intra-articular administration. Here, we synthesize an electrically charged cationic formulation of IGF-1 by using a short-length arginine-rich, hydrophilic cationic peptide carrier (CPC) with a net charge of +14, designed for rapid and high uptake and retention in both healthy and arthritic cartilage., Methods: IGF-1 was conjugated to CPC by using a site-specific sulfhydryl reaction via a bifunctional linker. Intra-cartilage depth of penetration and retention of CPC-IGF-1 was compared with the unmodified IGF-1. The therapeutic effectiveness of a single dose of CPC-IGF-1 was compared with free IGF-1 in an IL-1α-challenged cartilage explant culture post-traumatic OA model., Results: CPC-IGF-1 rapidly penetrated through the full thickness of cartilage creating a drug depot owing to electrostatic interactions with negatively charged aggrecan-glycosaminoglycans (GAGs). CPC-IGF-1 remained bound within the tissue while unmodified IGF-1 cleared out. Treatment with a single dose of CPC-IGF-1 effectively suppressed IL-1α-induced GAG loss and nitrite release and rescued cell metabolism and viability throughout the 16-day culture period, while free IGF at the equivalent dose was not effective., Conclusions: CPC-mediated depot delivery of IGF-1 protected cartilage by suppressing cytokine-induced catabolism with only a single dose. CPC is a versatile cationic motif that can be used for intra-cartilage delivery of other similar-sized drugs., (© 2022. The Author(s).)

In order to investigate the possible beneficial effects of GH administration on the aging process, 24-month-old rats of both sexes and 10-month-old SAMP8 mice were used. Male rats showed increased fat content and decreased lean body mass together with enhanced vasoconstriction and reduced vasodilation of their aortic rings compared to young adult animals. Chronic GH treatment for 10 weeks increased lean body mass and reduced fat weight together with inducing an enhancement of the vasodilatory response by increasing eNOS and a reduction of the constrictory responses. Old SAMP8 male mice also showed insulin resistance together with a decrease in insulin production by the endocrine pancreas and a reduced expression of differentiation parameters. GH treatment decreased plasma levels and increased pancreatic production of insulin and restored differentiation parameters in these animals. Ovariectomy plus low calcium diet in rabbits induced osteoporosis Titanium implants inserted into these rabbit tibiae showed after one month lesser bone to implant (BIC) surface and bone mineral density (BMD). Local application of GH in the surgical opening was able to increase BIC in the osteoporotic group. The hippocampus of old rats showed a reduction in the number of neurons and also in neurogenesis compared to young ones, together with an increase of caspases and a reduction of Bcl-2. GH treatment was able to enhance significantly only the total number of neurons. In conclusion, GH treatment was able to show beneficial effects in old animals on all the different organs and metabolic functions studied.

The cell proliferation effect of S-allyl-L-cysteine (SAC) and its mechanisms were examined in primary cultures of adult rat hepatocytes. In serum-free cultivation, SAC (10 -6  M)-stimulated hepatocytes showed significant proliferation compared to control at 5-h culture; the effect was dependent on the culture time and the dose of SAC (EC 50 value 8.58 × 10 -8  M). In addition, SAC-stimulated hepatocytes significantly increased mRNA expression levels of c-Myc and c-Fos at 1 h and cyclin B1 at 3.5 and 4 h, respectively. In contrast, alliin and allicin, structural analogs of SAC, did not show these effects observed with SAC. The SAC-induced hepatocyte proliferation effects were completely suppressed by monoclonal antibodies against growth hormone receptor and insulin-like growth factor type-I (IGF-I) receptor, respectively. Furthermore, the Janus kinase 2 (JAK2) inhibitor TG101209, phospholipase C (PLC) inhibitor U-73122, IGF-I receptor tyrosine kinase (RTK) inhibitor AG538, PI3 kinase inhibitor LY294002, MEK inhibitor PD98059, and mTOR inhibitor rapamycin completely suppressed the SAC-induced hepatocyte proliferation. JAK2 (p125 kDa) phosphorylation in cultured hepatocytes peaked 5 min after SAC stimulation. SAC-induced IGF-I RTK (p95 kDa) and ERK2 (p42 kDa) phosphorylation had slower rises than JAK2, peaking at 20 and 30 min, respectively. These results indicate that SAC promoted cell proliferation by growth hormone receptor/JAK2/PLC pathway activation followed by activation of the IGF-I RTK/PI3K/ERK2/mTOR pathway in primary cultures of adult rat hepatocytes., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Acute myocardial infarction (MI) induces an extensive sterile inflammation, which is dominated in the early phase by invading neutrophils and monocytes/macrophages. The inflammatory response after MI critically affects infarct healing and cardiac remodeling. Therefore, modulation of cardiac inflammation may improve outcome post MI. Insulin-like growth factor 1 (IGF1) treatment reduces infarct size and improves cardiac function after MI via IGF1 receptor mediated signaling in myeloid cells. Our study aimed to investigate the effect of IGF1 on neutrophil phenotype both in vitro and in vivo after MI. We show that IGF1 induces an anti-inflammatory phenotype in bone marrow derived neutrophils. On the molecular and functional level IGF1 treated neutrophils were indistinguishable from those induced by IL4. Surprisingly, insulin, even though it is highly similar to IGF1 did not create anti-inflammatory neutrophils. Notably, the IGF1 effect was independent of the canonical Ras/Raf/ERK or PI3K/AKT pathway, but depended on activation of the JAK2/STAT6 pathway, which was not activated by insulin treatment. Single cell sequencing analysis 3 days after MI also showed that 3 day IGF1 treatment caused a downregulation of pro-inflammatory genes and upstream regulators in most neutrophil and many macrophage cell clusters whereas anti-inflammatory genes and upstream regulators were upregulated. Thus, IGF1 acts like an anti-inflammatory cytokine on myeloid cells in vitro and attenuates the pro-inflammatory phenotype of neutrophils and macrophages in vivo after MI. IGF1 treatment might therefore represent an effective immune modulatory therapy to improve the outcome after MI., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Nederlof, Reidel, Spychala, Gödecke, Heinen, Lautwein, Petzsch, Köhrer and Gödecke.)

Insulin-like growth factor-1 (IGF-1) is a neurotrophic factor produced locally in the central nervous system which can promote axonal regeneration, protect motoneurons, and inhibit neuroinflammation. In this study, we used the zebrafish spinal transection model to investigate whether IGF-1 plays an important role in the recovery of motor function. Unlike mammals, zebrafish can regenerate axons and restore mobility in remarkably short period after spinal cord transection. Quantitative real-time PCR and immunofluorescence showed decreased IGF-1 expression in the lesion site. Double immunostaining for IGF-1 and Islet-1 (motoneuron marker)/GFAP (astrocyte marker)/Iba-1 (microglia marker) showed that IGF-1 was mainly expressed in motoneurons and was surrounded by astrocyte and microglia. Following administration of IGF-1 morpholino at the lesion site of spinal-transected zebrafish, swimming test showed retarded recovery of mobility, the number of motoneurons was reduced, and increased immunofluorescence density of microglia was caused. Our data suggested that IGF-1 enhances motoneuron survival and inhibits neuroinflammation after spinal cord transection in zebrafish, which suggested that IGF-1 might be involved in the motor recovery., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC part of Springer Nature.)

Tears in the rotator cuff are challenging to repair because of the complex, hypocellular, hypovascular, and movement-active nature of the tendon and its enthesis. Insulin-like Growth Factor-1 (IGF-1) is a promising therapeutic for this repair. However, its unstable nature, short half-life, and ability to disrupt homeostasis has limited its clinical translation. Pegylation has been shown to improve the stability and sustain IGF-1 levels in the systemic circulation without disrupting homeostasis. To provide localized delivery of IGF-1 in the repaired tendons, we encapsulated pegylated IGF-1 mimic and its controls (unpegylated IGF-1 mimic and recombinant human IGF-1) in polycaprolactone-based matrices and evaluated them in a pre-clinical rodent model of rotator cuff repair. Pegylated-IGF-1 mimic delivery reestablished the characteristic tendon-to-bone enthesis structure and improved tendon tensile properties within 8 weeks of repair compared to controls, signifying the importance of pegylation in this complex tissue regeneration. These results demonstrate a simple and scalable biologic delivery technology alternative to tissue-derived grafts for soft tissue repair., (© 2022 Wiley Periodicals LLC.)

Background and Objective: Type 2 diabetes mellitus (T2DM) is an endocrine disorder with pancreatic β cell dysfunction and/or reduced insulin sensitivity. IGF-1 is critically involved in pancreatic β cell growth, differentiation, and insulin secretion. Insulin-mediated IRS1/PI3K/Akt/FOXO1 signaling has been proved to be closely associated with pancreatic β cell function, hepatic glucose metabolism, and the development of T2DM. This present work was designed to demonstrate the protective role of IGF-1 against pancreatic β cell dysfunction and to probe into the underlying mechanisms., Methods: Herein, cell viability, cell apoptosis, insulin secretion, oxidative stress, and glycolysis in STZ-treated INS-1 cells were measured, so as to determine the biological function of IGF-1 against pancreatic β cell dysfunction in T2DM. Additionally, whether IGF-1 could activate IRS1/PI3K/Akt/FOXO1 signaling pathway to manipulate the progression of T2DM was also investigated., Results: It was discovered that IGF-1 treatment enhanced the viability and suppressed the apoptosis of STZ-treated INS-1 cells. Besides, IGF-1 treatment augmented insulin secretion of INS-1 cells in response to STZ. Moreover, IGF-1 exerted protective role against oxidative damage and displayed inhibitory effect on glycolysis in STZ-treated INS-1 cells. Mechanistically, IGF-1 treatment markedly boosted the activation of IRS1/PI3K/Akt/FOXO1 pathway. Furthermore, treatment with AG1024 (an inhibitor of IGF-1R) partially abolished the actions of IGF-1 on cell viability, cell apoptosis, insulin secretion, oxidative stress, and glycolysis in STZ-treated INS-1 cells., Conclusion: To conclude, IGF-1 could improve the viability and inhibit the apoptosis of STZ-treated pancreatic β cells, induce insulin secretion, alleviate oxidative damage, as well as arrest glycolysis by activating IRS1/PI3K/Akt/FOXO1 pathway., (© 2022. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Objectives: Some previous studies indicated that the excessive proliferation and migration of Pulmonary Artery Smooth Muscle Cells (PASMCs) could be observed in pulmonary artery intima after Pulmonary Embolism (PE) occurred. In addition, recent studies identified some miRNAs that are differentially expressed in the blood of PE patients, which might be used as a diagnostic biomarker for PE, including let-7a-5p, let-7b-5p, and miR-150-5p. Hence, the authors sought to explore the effects of let-7b-5p in PASMC proliferation and migration and the corresponding regulatory mechanism., Methods: Platelet-Derived Growth Factor (PDGF) was utilized to induce the hyper-proliferation model in PASMCs. The mRNA and protein expression levels were detected by RT-qPCR and western blot, respectively. The proliferation of PASMCs was evaluated by the detection of PCNA expression, as well as CCK-8 and Edu assays. Wound healing and Transwell assays were exploited to assess the migration ability of PASMCs. The targets of let-7b-5p were predicted based on two bioinformatics online tools. Dual-luciferase and Ago2 pull-down assays were applied to confirm the interaction between let-7b-5p and IGF1., Results: 40 ng/mL PDGF was selected as the optimal concentration to induce PASMCs. let-7b-5p mimics suppressed the proliferation and migration of PDGF-induced PASMCs, while let-7b-5p inhibitor led to the opposite result. In further mechanism exploration, IGF1 was predicted and confirmed as the direct target gene of let-7b-5p. The promotion role of IGF1 overexpression on the proliferation and migration of PDGF-induced PASMCs was dramatically countered by let-7b-5p mimics., Conclusion: let-7b-5p prohibits the proliferation and migration of PDGF-induced PASMCs by modulating IGF1., Competing Interests: Conflicts of interest The authors declare no conflicts of interest., (Copyright © 2022 HCFMUSP. Published by Elsevier España, S.L.U. All rights reserved.)

Insulin-like growth factor-I (IGF-I) signaling plays a key role in learning and memory. IGF-I increases the spiking and induces synaptic plasticity in the mice barrel cortex (Noriega-Prieto et al., 2021), favoring the induction of the long-term potentiation (LTP) by Spike Timing-Dependent Protocols (STDP) (Noriega-Prieto et al., 2021). Here, we studied whether these IGF-I effects depend on endocannabinoids (eCBs) and nitric oxide (NO). We recorded both excitatory postsynaptic currents (EPSCs) and inhibitory postsynaptic currents (IPSCs) evoked by stimulation of the basal dendrites of layer II/III pyramidal neurons of the Barrel Cortex and analyzed the effect of IGF-I in the presence of a CB 1 R antagonist, AM251, and inhibitor of the NO synthesis, L-NAME, to prevent the eCBs and the NO-mediated signaling. Interestingly, L-NAME abolished any modulatory effect of the IGF-I-induced excitatory and inhibitory transmission changes, suggesting the essential role of NO. Surprisingly, the inhibition of CB1Rs did not only block the potentiation of EPSCs but reversed to a depression, highlighting the remarkable functions of the eCB system. In conclusion, eCBs and NO play a vital role in deciding the sign of the effects induced by IGF-I in the neocortex, suggesting a neuromodulatory interplay among IGF-I, NO, and eCBs.

A woman's endocrine system plays a crucial role in orchestrating cellular interactions throughout her life. The growth hormone (GH) and insulin-like growth factor (IGF) system appears to impact crucial reproductive events and cell types of the ovary, such as granulosa cells, theca cells, and oocytes. Further, IGF1 is a cornerstone during embryonic development and influences predominantly developing and pre-antral follicles. In this commentary, we will emphasize the pleiotropic effects of IGF1 on physiological processes inside the egg. Herein, we will provide a brief overview on IGF1 related cell signal transduction pathways during the maturation and aging of oocytes. We aim to elucidate from a molecular and biochemical point of view if IGF1 in women with metabolic imbalances such as obesity or diabetes could be used in clinics as a novel, reliable estimator for the developmental competence of an oocyte.

Background: Steroid-induced osteonecrosis of the femoral head (SONFH) is a disorder that causes severe disability in patients and has a high incidence worldwide. Although glucocorticoid (GC)-induced apoptosis of osteoblasts is an important cytological basis of SONFH, the detailed mechanism underlying SONFH pathogenesis remains elusive. PI3K/AKT signaling pathway was reported to involve in cell survival and apoptosis., Objective: We explored the role of PI3K/AKT/FOXO1 signaling pathway and its downstream targets during glucocorticoid -induced osteonecrosis of the femoral head., Methods: We obtained gene expression profile of osteoblasts subjected to dexamethasone (Dex) treatment from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) were screened out and functional enrichment analysis were conducted by bioinformatics analysis. In vitro , we analyzed Dex-induced apoptosis in MC3T3-E1 cells and explored the role of PI3K/AKT/FOXO1 signaling pathway in this phenomenon by employing siRNA-FOXO1 and IGF-1(PI3K/AKT agonist). Finally, we verified our results in a rat model of SONFH., Results: In Dex-treated osteoblasts, DEGs were mainly enriched in the FOXO signaling pathway. Dex inhibited MC3T3-E1 cell viability in a dose-dependent effect and induced apoptosis by increasing the expression levels of FOXO1, Bax, cleaved-Caspase-3, and cleaved-Caspase-9, while reducing the expression of Bcl-2. Notably, these results were reversed by siRNA-FOXO1 treatment. Dex inhibited PI3K/AKT signaling pathway, upregulated FOXO1 expression and increased FOXO1 nuclear translocation, which were reversed by IGF-1. Compared to normal rats, the femoral head of SONFH showed increased expression of FOXO1, increased number of apoptotic cells, and empty osteocytic lacunas, as well as decreased bone tissue content and femoral head integrity. Significantly, the effects of GC-induced SONFH were alleviated following IGF-1 treatment., Conclusion: Dex induces osteoblast apoptosis via the PI3K/AKT/FOXO1 signaling pathway. Our research offers new insights into the underlying molecular mechanisms of glucocorticoid-induced osteonecrosis in SONFH and proposes FOXO1 as a therapeutic target for this disease., Competing Interests: The authors declare there are no competing interests., (©2022 Sun et al.)

The increasing rates of morbidity and mortality caused by ischemic heart disease pose a serious threat to human health. Long non‑coding (lnc)RNA small nucleolar RNA host gene 1 (SNHG1) has a protective effect on the myocardium. In the present study, the role of lncRNA SNHG1 in myocardial ischemia reperfusion injury (MIRI) and the underlying mechanisms were investigated. After hypoxia/reoxygenation (H/R) induction, the expression levels of lncRNA SNHG1 were detected using reverse transcription‑quantitative PCR. After lncRNA SNHG1 overexpression via cell transfection, cell viability was detected using an MTT assay, apoptotic rates were detected using TUNEL staining, apoptosis‑related protein expression levels were detected using western blotting and respective kits were used to measure the oxidative stress levels. The Encyclopedia of RNA Interactomes database predicted the presence of binding sites between lncRNA SNHG1 and microRNA (miR)‑450b‑5p, and between miR‑450b‑5p and insulin‑like growth factor 1 (IGF1). These interactions were then verified using luciferase reporter assays. Subsequently, the regulatory mechanism underlying the lncRNA SNHG1/miR‑450b‑5p/IGF1 axis in MIRI was investigated by overexpressing miR‑450b‑5p and knocking down IGF1 expression in H/R‑induced cells. Finally, the expression of PI3K/Akt signaling pathway‑related proteins was detected using western blotting. lncRNA SNHG1 expression was significantly downregulated in H/R‑induced AC16 cells. lncRNA SNHG1 overexpression significantly inhibited apoptosis and decreased oxidative stress levels in H/R‑induced AC16 cells, which was mediated via regulation of the miR‑450b‑5p/IGF1 axis and activation of the PI3K/Akt signaling pathway. Therefore, the present study suggested that activation of the PI3K/Akt signaling pathway via the lncRNA SNHG1/miR‑450b‑5p/IGF1 axis inhibited the apoptosis and oxidative stress levels of H/R‑induced AC16 cells.

Objectives: Dentofacial orthopaedic treatment of mandibular hypoplasia has unpredictable skeletal outcomes. Although several biomodulators including insulin-like growth factor 1 (IGF-1) are known to contribute to chondrocyte proliferation, their efficacy in modulating mandibular growth has not been validated. The aim of this study was to determine the effect of locally delivered IGF-1 on mandibular growth and condylar bone quality/quantity in juvenile rats., Setting and Sample Population: Institutional vivarium using twenty-four 35-day-old male Sprague-Dawley rats., Methods: PBS or 40 µg/kg (low-dose) IGF-1 or 80 µg/kg (high-dose) IGF-1 was injected bilaterally into the temporomandibular joints of the rats at weekly intervals for four weeks. Cephalometric and micro-computed tomography measurements were used to determine mandibular dimensions. Bone and tissue mineral density, volume fraction and mineral content were determined, and serum IGF-1 concentrations assayed., Results: Intra-articular administration of high-dose IGF-1 contributed to a significant 6%-12% increase in mandibular body and condylar length compared to control and low-dose IGF-1-treated animals. Additionally, IGF-1 treatment resulted in a significant decrease in the angulation of the lower incisors to mandibular plane. Condylar bone volume, bone volume fraction, mineral content and mineral density were significantly increased with high-dose IGF-1 relative to control and low-dose IGF-1 groups. Serum IGF-1 levels were similar between all groups confirming limited systemic exposure to the locally administered IGF-1., Conclusion: Local administration of high-dose 80 µg/kg IGF-1 enhances mandibular growth and condylar bone quality and quantity in growing rats. The findings have implications for modulating mandibular growth and potentially enhancing condylar bone health and integrity., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The quality and developmental capacity of oocytes derived from in vitro maturation (IVM) remain unsatisfactory, which greatly impairs the efficiency and application of embryo technologies. The present experiment was designed to investigate the effect of the supplementation of EGF, IGF-1, and Cx37 in an IVM medium on the maturation quality and development ability of bovine oocytes. The cytoplasmic maturation events of oocytes and the quality of in vitro fertilization (IVF) blastocysts were examined to investigate the relative mechanisms. Our results showed that the nuclear maturation and blastocyst development after the IVF of oocytes treated with 25 μg/mL Cx37 or the combination of 50 ng/mL EGF and 100 ng/mL IGF-1 were significantly increased compared to those of the control group (p < 0.05). Furthermore, the blastocyst rate, and blastocyst total cell number and survival rate after vitrification of the EGF+IGF-1+Cx37 group, were significantly higher than those of the control group (p < 0.05), but lower than those of the FSH+LH+EGF+IGF-1+Cx37 group (p < 0.05). The transzonal projection (TZP) intensity, glutathione (GSH) level, and mitochondrial function of the EGF+IGF-1+Cx37 group were significantly higher than that of the control group, and lower than those of the FSH+LH+EGF+IGF-1+Cx37 group, in contrast to the results of the reactive oxygen species (ROS) levels. In conclusion, our results showed that the supplementation of 50 ng/mL EGF, 100 ng/mL IGF-1, and 25 μg/mL Cx37 in the IVM of bovine oocytes significantly improved their quality and developmental ability by increasing the TZP, mitochondrial function, and GSH level.

Background: In children, recombinant human growth hormone (rhGH) therapy for treatment of short stature has raised concerns of the early onset of puberty. Puberty is initiated by the activation of the hypothalamus-pituitary-gonad axis. Insulin-like growth factor-1 (IGF1) has been known to mediate physiologic effects of GH. To understand the mechanism of precocious sexual maturation following prepubertal GH therapy, the effects of rhGH on the hypothalamus-pituitary-gonad axis were examined in the immature male rats., Methods: Immature male rats were given by daily injection of rhGH (1 or 2 IU/kg) from postnatal day (PND) 21 to PND 23 or 30. The effects of rhGH on kisspeptin-GnRH-LH system in the hypothalamus-pituitary axis, systemic and testicular IGF1, spermatogenesis, steroidogenesis, and circulating testosterone levels were examined. The effects of rhGH on the IGF1 expression and steroidogenesis were examined in progenitor LCs in vitro., Results: Testicular steroidogenic pathway and spermatogenesis marker mRNA levels, number and size of 17β-hydroxysteroid dehydrogenase (+) LCs, and blood testosterone levels of rhGH rats were significantly higher than those of controls on PNDs 24 and 31. Hypothalamic Kiss1 and Gnrh1 mRNA of rhGH rats were significantly higher than those of controls on PND 24, indicating early activation of hypothalamic kisspeptin-GnRH neurons by rhGH. Hypothalamic Igf1 mRNA levels of rhGH rats were significantly higher than those of controls on PND 24 but significantly lower than those of controls on PND 31. Testicular Igf1 mRNA levels were significantly higher in rhGH rats than in the controls on PNDs 24 and 31 whereas circulating IGF1 levels were not. In progenitor LCs, rhGH significantly increased Igf1 and steroidogenic pathway mRNA levels and testosterone production., Conclusions: Local increases in testicular IGF1 might be an important mediator of gonadal maturation via activation of LCs steroidogenesis in immature rats given rhGH., (© 2022. The Author(s).)

Sleep deprivation negatively influences cognition, however, the regulatory mechanisms to counteract this effect have not been identified. IGF-1 has been shown to be anti-inflammatory and neuroprotective in CNS injury models. In this study, we determined the impact of IGF-1 on brain injury and inflammation while modeling sleep deprivation. We found that IGF-1 was downregulated in human peripheral blood and in mice subjected to sleep deprivation for 5 days, with reduced activation of the downstream PI3K/AKT/GSK-3β pathway in mice brains. In addition, we found reduced levels of the anti-apoptosis enzyme Bcl-2 and increased levels of pro-apoptosis enzyme Caspase-9 expression, together with increased pro-inflammatory factors. The administration of IGF-1 after sleep deprivation induced activation of the PI3K/AKT/GSK-3β pathway, reversed changes in Bcl-2, Caspase-9, and pro-inflammatory factors, and alleviated cognitive impairment. Notably, IGF-1 also induced activation of the PI3K/AKT/GSK-3β pathway, and displayed anti-apoptosis and anti-inflammatory properties under normal sleep conditions,while IGF-1 did not improve the cognition under normal sleep conditions. These results suggest that the IGF-1/PI3K/AKT/GSK-3β pathway is involved in the regulation of cognitive function after sleep deprivation through modulation of apoptosis and inflammatory response. IGF-1 could be a viable therapeutic target, though further investigation is required to better understand its role in sleep deprivation., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Insulin-like growth factor-1 (IGF-1), a member of the insulin family, has a high degree of homology with insulin and exhibits anti-inflammatory and anti-oxidative stress properties. However, the potential protective effect of IGF-1 on hyperoxia-induced lung injury remains unknown. In this study, we aimed to explore the effects and mechanism of action of IGF-1 in hyperoxia-induced lung injury in neonatal rats. Materials and Methods: Hematoxylin-eosin staining was used to observe pathological changes in lung tissue; transmission electron microscopy was used to examine the ultrastructure, and ELISA was used to detect the level of pro-inflammatory cytokines in bronchoalveolar lavage fluid. Further, malondialdehyde, glutathione, and superoxide dismutase activities in lung tissue were evaluated. TUNEL staining was used to detect cell apoptosis, and western blot analysis was used to detect the expression of Bax, Bcl-2, Caspase-3, p-PERK, p-eIF2α, ATF4, and CHOP in the lung tissue. Moreover, the wet/dry weight ratio of lung tissue was determined. Results: Intraperitoneal injection of IGF-1 effectively reduced lung tissue damage induced by hyperoxia; production of inflammatory cells and release of pro-inflammatory cytokines, oxidative stress, and cell apoptosis. Further, IGF-1 down-regulated the expression of ATF4, CHOP, and Bax/Bcl-2, and inhibited the phosphorylation of PERK and eIF2α. Conclusion: The results suggest that IGF-1 reduces hyperoxia-induced lung inflammation and oxidative stress in neonatal rats through the PERK/eIF2α/ATF4/CHOP signaling pathway and inhibits cell apoptosis.

Acne vulgaris is the most common disease of the pilosebaceous unit. The pathogenesis of this disease is complex, involving increased sebum production and perifollicular inflammation. Understanding the factors that regulate sebum production is important in identifying novel therapeutic targets for the treatment of acne. Bee Venom (BV) and melittin have multiple effects including antibacterial, antiviral, and anti-inflammatory activities in various cell types. However, the anti-lipogenic mechanisms of BV and melittin have not been elucidated. We investigated the effects of BV and melittin in models of Insulin-like growth factor-1 (IGF-1) or Cutibacterium acnes ( C. acnes )-induced lipogenic skin disease. C. acnes or IGF-1 increased the expression of sterol regulatory element-binding protein-1 (SREBP-1) and proliferator-activated receptor gamma (PPAR-γ), transcription factors that regulate numerous genes involved in lipid biosynthesis through the protein kinase B (Akt)/mammalian target of rapamycin (mTOR)/SREBP signaling pathway. In this study using a C. acnes or IGF-1 stimulated lipogenic disease model, BV and melittin inhibited the increased expression of lipogenic and pro-inflammatory factor through the blockade of the Akt/mTOR/SREBP signaling pathway. This study suggests for the first time that BV and melittin could be developed as potential natural anti-acne agents with anti-lipogenesis, anti-inflammatory, and anti- C. acnes activity.

Aging is accompanied by a decline in cognition that can be due to a lower IGF-I level. We studied response facilitation induced in primary somatosensory (S1) cortical neurons by repetitive stimulation of whiskers in young and old mice. Layer 2/3 and 5/6 neurons were extracellularly recorded in young (≤ 6 months of age) and old (≥ 20 month of age) anesthetized mice. IGF-I injection in S1 cortex (10 nM; 0.2 μL) increased whisker responses in young and old animals. A stimulation train at 8 Hz induced a long-lasting response facilitation in only layer 2/3 neurons of young animals. However, all cortical neurons from young and old animals showed long-lasting response facilitation when IGF-I was applied in the S1 cortex. The reduction in response facilitation in old animals can be due to a reduction in the IGF-I receptors as was indicated by the immunohistochemistry study. Furthermore, a reduction in the performance of a whisker discrimination task was observed in old animals. In conclusion, our findings indicate that there is a reduction in the synaptic plasticity of S1 neurons during aging that can be recovered by IGF-I. Therefore, it opens the possibility of use IGF-I as a therapeutic tool to ameliorate the effects of heathy aging.

The neuroplastic mechanism of sex reversal in the fish brain remains unclear due to the difficulty in identifying the key neurons involved. Mozambique tilapia show different reproductive behaviours between sexes; males build circular breeding nests while females hold and brood fertilized eggs in their mouth. In tilapia, gonadotropin-releasing hormone 3 (GnRH3) neurons, located in the terminal nerve, regulate male reproductive behaviour. Mature males have more GnRH3 neurons than mature females, and these neurons have been indicated to play a key role in the androgen-induced female-to-male sex reversal of the brain. We aimed to elucidate the signalling pathway involved in the androgen-induced increase in GnRH3 neurons in mature female tilapia. Applying inhibitors to organotypic cultures of brain slices, we showed that the insulin-like growth factor (IGF)-1 receptor (IGF-1R)/PI3K/AKT/mTOR pathway contributed to the androgen-induced increase in GnRH3 neurons. The involvement of IGF-1 and IGF-1R in 11-ketotestosterone (11-KT)-induced development of GnRH3 neurons was supported by an increase in Igf-1 mRNA shortly after 11-KT treatment, the increase of GnRH3 neurons after IGF-1 treatment and the expression of IGF-1R in GnRH3 neurons. Our findings highlight the involvement of IGF-1 and its downstream signalling pathway in the sex reversal of the tilapia brain., (© 2022. The Author(s).)

Growth hormone (Gh) regulates somatic growth in fishes, particularly through the Gh - insulin-like growth factor-I (Igf-I) axis. In this study, recombinant Japanese eel Ghs with or without C-terminal peptides of human chorionic gonadotropin (CTP), which are known to prolong the half-life, were produced using the HEK 293 and CHO expression system. The effect of recombinant Gh administration to eel larvae on their somatic growth was investigated in short-term feeding experiments, and it was found that three types of recombinant Ghs with CTP (CTP-reGh, reGh-CTP and reGh-CTP × 2) were more effective in promoting somatic growth in eel larvae than recombinant Ghs without CTP. Among the three recombinant Ghs with CTP, reGh-CTP × 2 had the highest growth-promoting effects, however only when provided in the short term. After long-term administration of reGh-CTP × 2, there was no difference in growth between the Gh administrated group and the control group. The survival rate of eel larvae were not affected by recombinant Ghs. In addition, the mRNA expression of gh, Gh receptors, Igf-I and IGF-II were measured by quantitative real-time PCR, and significant reductions in the expression of gh, Gh receptors and Igf-I were observed. These findings provide useful tools to study the mechanisms of somatic growth and increase understanding of Gh regulation in anguillid eel larvae., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Amino acids (AA) and IGF1 have been demonstrated to play essential roles in protein synthesis and fish muscle growth. The myoblast cell culture is useful for studying muscle regulation, and omics data have contributed enormously to understanding its molecular biology. However, to our knowledge, no study has performed the large-scale sequencing of fish-cultured muscle cells stimulated with pro-growth signals. In this work, we obtained the transcriptome and microRNAome of pacu ( Piaractus mesopotamicus )-cultured myotubes treated with AA or IGF1. We identified 1228 and 534 genes differentially expressed by AA and IGF1. An enrichment analysis showed that AA treatment induced chromosomal changes, mitosis, and muscle differentiation, while IGF1 modulated IGF/PI3K signaling, metabolic alteration, and matrix structure. In addition, potential molecular markers were similarly modulated by both treatments. Muscle-miRNAs ( miR-1 , -133 , -206 and -499 ) were up-regulated, especially in AA samples, and we identified molecular networks with omics integration. Two pairs of genes and miRNAs demonstrated a high-level relationship, and involvement in myogenesis and muscle growth: marcksb and miR-29b in AA, and mmp14b and miR-338-5p in IGF1. Our work helps to elucidate fish muscle physiology and metabolism, highlights potential molecular markers, and creates a perspective for improvements in aquaculture and in in vitro meat production.

The mechanism of insulin-like growth factor type-I (IGF-I) secretion stimulated by S-allyl-L-cysteine (SAC) was investigated as part of a study of SAC-induced DNA synthesis and cell proliferation in primary cultures of adult rat hepatocytes. When 10 -6  M SAC was added to the culture, the amount of IGF-I in the medium was significantly increased at 10 min. The peak IGF-I level (140 pg/mL) was observed 20 min after SAC stimulation. The SAC-induced IGF-I secretion was completely suppressed by a selective Janus kinase 2 (JAK2) inhibitor (TG101209), a selective phospholipase C (PLC) inhibitor (U-73122), an intracellular Ca 2+ chelating agent (BAPTA-AM), and a granule secretion inhibitor (somatostatin). On the other hand, 10 -6  M SAC-stimulated hepatocytes showed increased intracellular Ca 2+ concentration in a time-dependent manner from 0 to 10 min. Phosphorylation of SAC-induced JAK2 and IGF-I receptor tyrosine kinase (RTK) was completely suppressed by TG101209. In addition, U-73122, BAPTA-AM, and somatostatin did not suppress SAC-induced JAK2 phosphorylation, but significantly suppressed SAC-induced IGF-I RTK phosphorylation. Furthermore, binding of the monoclonal antibody against growth hormone (GH) to GH receptor was dose-dependently suppressed by SAC on immunofluorescence. These results showed that SAC promotes cell proliferation by stimulating GH receptor/JAK2/phospholipase C pathways and promoting autocrine secretion of IGF-I in primary cultures of adult rat hepatocytes.

Introduction: Diabetic gastroparesis (DGP) is a common chronic complication of diabetes characterized by decreased gastric motility, and an effective number of gastric smooth muscle cells (GSMCs) ensures gastric motility. A previous study documented that apoptosis was present in gastric smooth muscles in rats with DGP and adenosine monophosphate-activated protein kinase (AMPK) was an important factor of apoptosis of rat GSMCs cultured under high glucose conditions. This study aimed to explore the effect of insulin-like growth factor-1 (IGF-1) on apoptosis of high glucose cultured rat GSMCs after silencing of AMPK and elucidate the underlying mechanism., Material and Methods: A total of 120 rats were divided into normal control (NC, n = 20), diabetic gastroparesis (DGP, n = 50) and DGP + IGF-1 (n = 50) groups. After establishing the rat model of DGP, rats in the DGP+IGF-1 group received an intraperitoneal injection of IGF-1 at a dose of 1.5 μg/kg/d for 10 weeks. The level of AMPK activity, liver kinase B1 (LKB1) activity, and calcium/calmodulin-dependent protein kinase b (CaMKKb) expression in rat gastric smooth muscle tissues was detected by Western blot analysis. Apoptosis in rat gastric smooth muscle tissues was detected by TUNEL assay. We also cultured rat GSMCs in vitro under high glucose (HG) condition (35 mM), incubated cells with IGF-1, and silenced AMPK with siRNA. The cells were divided into HG, HG + IGF-1, HG + siRNA, and HG + siRNA + IGF-1 groups. The apoptosis rates of rat GSMCs after silencing AMPK were detected by TUNEL assay and flow cytometry, and apoptosis-related protein expression in rat GSMCs was detected by Western blot., Results: IGF-1 decreased LKB1 activity, CaMKKb expression, AMPK activity, and inhibited apoptosis in rat gastric smooth muscle tissues. Compared with rat GSMCs cultured in vitro under HG conditions, apoptosis rates were reduced after treatment with IGF-1 and AMPK silencing (both p < 0.01). Apoptosis rates were higher in the HG + siRNA group compared with the HG + IGF-1 group (p < 0.05). IGF-1 down-regulated the expression of calcium/calmodulin-dependent kinase II (CaMKII) and p53, up-regulated the expression of p21, PLC-b3, PI3K p110 Ser1070, and the activities of Akt, p70S6K, mTORC1, and mTORC2. IGF-1 also up-regulated Bcl-2 expression and down-regulated the expression of BAX and Caspase-3., Conclusions: IGF-1 can inhibit the apoptosis of rat GSMCs under high glucose conditions, its mechanism may be related to the regulation of expression and activity of p53, PI3K, TSC-2, Akt, mTOR, 4E-BP1, p70S6K, p21, CaMKII, and PLC-b3 in rat GSMCs acting through AMPK pathway.

Background: The number of cases of male infertility is steadily growing every year, and therefore it is necessary to develop new methods for the diagnosis and treatment of this disease. It is known that plasma enriched with platelets, the α-granules of which contain growth factors, possesses high regenerative activity; therefore, we can expect positive results from its use for the restoration of spermatogenic epithelium., Objective: Morphological assessment of spermatogenesis after local β-irradiation with a dose of 8 Gy and the introduction of growth factors., Material and Methods: Wistar rats ( n =135) were divided into groups: I - Control, II - 8IR, III - 8IR+LP-PRP+IGF, IV - 8IR+LP-PRP, and V - LP-PRP. Spermatogenesis in animals of groups II, III, and IV was inhibited by a single local irradiation with 8 Gy electrons. Then, for 11 weeks, LP-PRP was injected intraperitoneally to rats III and IV, and in group III - additionally IGF-1. The testes were examined by light microscopy, computer morphometry, micro-CT, and Western blotting., Results: After irradiation, a decrease in spermatogenic epithelium and the number of germ cells was observed up to sub- and total germinal aplasia, fibrosis and an increase in the expression of caspase-3. Against the background of LP-PRP+IGF administration, the decrease in the proportion of germ cells (hypospermatogenesis) was less pronounced., Conclusion: The introduction of growth factors and other biologically active substances released from the α-granules of LP-PRP platelets leads to a delayed decrease in the quantitative and qualitative indicators of spermatogenesis, and the additional administration of IGF-1 enhances the regenerative processes that counteract the development of the effects of electron irradiation with a dose of 8 Gy.

Background & Objective: The insulin/IGF-1R/PI3K/Akt signalling cascade is increasingly being linked to breast cancer development, with aldose reductase (AR) playing a key role in mediating the crosstalk between this pathway and angiogenesis. The current study was designed to investigate whether nimbolide, a neem limonoid, targets the oncogenic signaling network to prevent angiogenesis in breast cancer., Methods: Breast cancer cells (MCF-7, MDA-MB-231), EAhy926 endothelial cells, MDA-MB-231 xenografted nude mice, and tumour tissues from breast cancer patients were used for the study. The expression of AR and key players in IGF-1/PI3K/Akt signaling and angiogenesis was evaluated by qRT-PCR, immunoblotting, and immunohistochemistry. Molecular docking and simulation, overexpression, and knockdown experiments were performed to determine whether nimbolide targets AR and IGF-1R., Results: Nimbolide inhibited AR with consequent blockade of the IGF-1/PI3K/Akt and /HIF-1alpha/VEGF signalling circuit by influencing the phosphorylation and intracellular localisation of key signaling molecules. The downregulation of DNMT-1, HDAC-6, miR-21, HOTAIR, and H19 with the upregulation of miR-148a/miR-152 indicated that nimbolide regulates AR and IGF-1/PI3K/Akt signaling via epigenetic modifications. Coadministration of nimbolide with metformin and the chemotherapeutic drugs tamoxifen/cisplatin displayed higher efficacy than single agents in inhibiting IGF-1/PI3K/Akt/AR signaling. Grade-wise increases in IGF-1R and AR expression in breast cancer tissues underscore their value as biomarkers of progression., Conclusion: This study provides evidence for the anticancer effects of nimbolide in cellular and mouse models of breast cancer besides providing leads for new drug combinations. It has also opened up avenues for investigating potential molecules such as AR for therapeutic targeting of cancer., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Background & Aims: Leucine-rich repeat-containing G-protein-coupled receptor-5 (Lgr5)+/olfactomedin-4 (Olfm4)+ intestinal stem cells (ISCs) in the crypt base are crucial for homeostatic maintenance of the epithelium. The gut hormone, glucagon-like peptide-2 1-33 (GLP-2), stimulates intestinal proliferation and growth; however, the actions of GLP-2 on the Lgr5+ ISCs remain unclear. The aim of this study was to determine whether and how GLP-2 regulates Lgr5+ ISC cell-cycle dynamics and numbers., Methods: Lgr5-Enhanced green-fluorescent protein - internal ribosome entry site - Cre recombinase - estrogen receptor T2 (eGFP-IRES-creERT2) mice were acutely administered human Glycine 2 (Gly2)-GLP-2, or the GLP-2-receptor antagonist, GLP-2 3-33 . Intestinal epithelial insulin-like growth factor-1-receptor knockout and control mice were treated chronically with human Gly2 (hGly2)-GLP-2. Cell-cycle parameters were determined by 5-Ethynyl-2'-deoxyuridine (EdU), bromodeoxyuridine, antibody #Ki67, and phospho-histone 3 labeling and cell-cycle gene expression., Results: Acute hGly2-GLP-2 treatment increased the proportion of eGFP+EdU+/OLFM4+EdU+ cells by 11% to 22% (P < .05), without affecting other cell-cycle markers. hGly2-GLP-2 treatment also increased the ratio of eGFP+ cells in early to late S-phase by 97% (P < .001), and increased the proportion of eGFP+ cells entering S-phase by 218% (P < .001). hGly2-GLP-2 treatment induced jejunal expression of genes involved in cell-cycle regulation (P < .05), and increased expression of Mcm3 in the Lgr5-expressing cells by 122% (P < .05). Conversely, GLP-2 3-33 reduced the proportion of eGFP+EdU+ cells by 27% (P < .05), as well as the expression of jejunal cell-cycle genes (P < .05). Finally, chronic hGly2-GLP-2 treatment increased the number of OLFM4+ cells/crypt (P < .05), in an intestinal epithelial insulin-like growth factor-1-receptor-dependent manner., Conclusions: These findings expand the actions of GLP-2 to encompass acute stimulation of Lgr5+ ISC S-phase entry through the GLP-2R, and chronic induction of Lgr5+ ISC expansion through downstream intestinal insulin-like growth factor-1 signaling., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: How to reduce the neurodevelopmental toxicity of decabromodiphenyl ether ( PBDE-209 ) remains unclear. This study investigated neurodevelopmental toxicity of PBDE-209 and the protective effects of insulin-like growth factor-1 (IGF-1)., Methods: Pregnant Sprague-Dawley rats were treated with PBDE-209 and IGF-1, and the offspring were subjected to the Morris Water Maze test. Hippocampal neurons were cultured with PBDE-209 and IGF-1 or the PI3K inhibitor or MEK inhibitor for cell viability, apoptosis, immunofluorescence, and Western blot assays., Results: Prenatal PBDE-209 exposure impaired the learning and memory ability of rats by delaying the mean latency to the platform compared, whereas prenatal treatment with IGF-1 treatment improved the learning and memory ability. In vitro, treatment of primary cultured hippocampal neural stem cells (H-NSCs) with PBDE-209 reduced cell proliferation and differentiation, but induced apoptosis. In contrast, IGF-1 treatment antagonized the cytotoxic effects of PBDE-209 in H-NSCs in vitro. At the gene level, IGF-1 inhibition of PBDE-209-induced cell cytotoxicity was through the activation of the PI3K/AKT and MEK/ERK signaling pathways in vitro because the effect of IGF-1 was blocked by the AKT inhibitor LY294002 and the ERK1/2 inhibitor PD98059., Conclusion: Prenatal PBDE-209 exposure impaired the learning and memory ability of rats, whereas IGF-1 treatment was able to inhibit the neurodevelopmental toxicity of PBDE-209 by activation of the PI3K/AKT and ERK1/2 cell pathways.

The present study aimed to prepare a kind of controlled-releasing insulin-like growth factor 1 (IGF-1)/spider silk protein nanofibrous membrane using a electrostatic spinning method and evaluated its effect on the cell viability of endothelial progenitor cells (EPCs). Recombinant spidroin named as GMCDRSSP-IgF-1 was electro-spun into nanofibrous membrane which can be degraded by protease and be capable of sustained-release of IGF-1. The membrane can be degraded after being treated with thrombin. The release assay results showed that IGF-1 concentration could be maintained at 20 ng/ml for a long time with treatment of Tobacco Etch Virus (TEV) protease. The viability of EPCs on GMCDRSSP-IgF-1 nanofibrous membrane was significantly increased with the presence of TEV protease. The controlled and sustained release of IGF-1 from the nanofibrous membrane could promote the adhesion and viability of EPCs. In summary, the nanofibrous membrane that exhibits controlled degradation and sustained release of IGF-1 was prepared with electrostatic spinning from genetically modified recombinant spider silk protein. The nanofibrous membrane exhibited good blood compatibility and cytocompatibility. With the presence of TEV protease, the sustained-release of IGF-1 significantly promoted the adhesion and viability of EPCs. The new nanofibrous membrane can be potentially used as a scaffold for EPCs culture in vitro and future in vivo studies.

Dynamic regulation of G-protein-coupled receptor (GPCR) kinase 2 (GRK2) expression restores cellular function by protecting from overstimulation via GPCR and non-GPCR signaling. In the primary afferent neurons, GRK2 negatively regulates nociceptive tone. The present study tested the hypothesis that induction of GRK2 in the primary afferent neurons contributes to the resolution of acute pain after tissue injury. GRK2 expression in the dorsal root ganglion (DRG) was analyzed at 1 and 7 days after the incision. Intraperitoneal administration of a GRK2 inhibitor was performed 7 days post-incision in male Sprague-Dawley rats who underwent plantar incisions to analyze the pain-related behavioral effect of the GRK2 inhibitor. Separately, GRK2 expression was analyzed after injecting insulin-like growth factor 1 (IGF1) into the rat hind paw. In addition, an IGF1 receptor (IGF1R) inhibitor was administered in the plantar incision rats to determine its effect on the incision-induced hyperalgesia and GRK2 expression. Plantar incision induced an increase in GRK2 in the DRG at 7 days, but not at 1 day post-incision. Acute hyperalgesia after the plantar incision disappeared by 7 days post-incision. Intraperitoneal injection of the GRK2 inhibitor at this time reinstated mechanical hyperalgesia, although the GRK2 inhibitor did not produce hyperalgesia in naive rats. After the incision, IGF1 expression increased in the paw, but not in the DRG. Intraplantar injection of IGF1 increased GRK2 expression in the ipsilateral DRG. IGF1R inhibitor administration prevented both the induction of GRK2 and resolution of hyperalgesia after the plantar incision. These findings demonstrate that induction of GRK2 expression driven by tissue IGF1 has potent analgesic effects and produces resolution of hyperalgesia after tissue injury. Dysregulation of IGF1-GRK2 signaling could potentially lead to failure of the spontaneous resolution of acute pain and, hence, development of chronic pain after surgery., (Copyright © 2021. Published by Elsevier Inc.)

Insulin-like growth factor 1 (IGF-1) has neuroprotective actions, including vasodilatory, anti-inflammatory, and antithrombotic effects, following ischemic stroke. However, the molecular mechanisms underlying the neuroprotective effects of IGF-1 following ischemic stroke remain unknown. Therefore, in the present study, we investigated whether IGF-1 exerted its neuroprotective effects by regulating the Hippo/YAP signaling pathway, potentially via activation of the PI3K/AKT cascade, following ischemic stroke. In the in vitro study, we exposed cultured PC12 and SH-5YSY cells, and cortical primary neurons, to oxygen-glucose deprivation. Cell viability was measured using CCK-8 assay. In the in vivo study, Sprague-Dawley rats were subjected to middle cerebral artery occlusion. Neurological function was assessed using a modified neurologic scoring system and the modified neurological severity score (mNSS) test, brain edema was detected by brain water content measurement, infarct volume was measured using triphenyltetrazolium chloride staining, and neuronal death and apoptosis were evaluated by TUNEL/NeuN double staining, HE and Nissl staining, and immunohistochemistry staining for NeuN. Finally, western blot analysis was used to measure the level of IGF-1 in vivo and levels of YAP/TAZ, PI3K and phosphorylated AKT (p-AKT) both in vitro and in vivo. IGF-1 induced activation of YAP/TAZ, which resulted in improved cell viability in vitro, and reduced neurological deficits, brain water content, neuronal death and apoptosis, and cerebral infarct volume in vivo. Notably, the neuroprotective effects of IGF-1 were blocked by an inhibitor of the PI3K/AKT cascade, LY294002. LY294002 treatment not only downregulated PI3K and p-AKT, but YAP/TAZ as well, leading to aggravation of neurological dysfunction and worsening of brain damage. Our findings indicate that the neuroprotective effects of IGF-1 are, at least in part mediated by upregulation of YAP/TAZ via activation of the PI3K/AKT cascade following cerebral ischemic stroke., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Inflammatory bowel diseases (IBD), represented by ulcerative colitis (UC) and Crohn's disease (CD), are characterized by chronic inflammation of the gastrointestinal tract, what leads to diarrhea, malnutrition, and weight loss. Depression of the growth hormone-insulin-like growth factor-1 axis (GH-IGF-1 axis) could be responsible of these symptoms. We demonstrate that long-term treatment (54 weeks) of adult CD patients with adalimumab (ADA) results in a decrease in serum IGF-1 without changes in serum IGF-1 binding protein (IGF1BP4). These results prompted us to conduct a preclinical study to test the efficiency of IGF-1 in the medication for experimental colitis. IGF-1 treatment of rats with DSS-induced colitis has a beneficial effect on the following circulating biochemical parameters: glucose, albumin, and total protein levels. In this experimental group we also observed healthy maintenance of colon size, body weight, and lean mass in comparison with the DSS-only group. Histological analysis revealed restoration of the mucosal barrier with the IGF-1 treatment, which was characterized by healthy quantities of mucin production, structural maintenance of adherers junctions (AJs), recuperation of E-cadherin and β-catenin levels and decrease in infiltrating immune cells and in metalloproteinase-2 levels. The experimentally induced colitis caused activation of apoptosis markers, including cleaved caspase 3, caspase 8, and PARP and decreases cell-cycle checkpoint activators including phosphorylated Rb, cyclin E, and E2F1. The IGF-1 treatment inhibited cyclin E depletion and partially protects PARP levels. The beneficial effects of IGF-1 in experimental colitis could be explained by a re-sensitization of the IGF-1/IRS-1/AKT cascade to exogenous IGF-1. Given these results, we postulate that IGF-1 treatment of IBD patients could prove to be successful in reducing disease pathology., (Copyright © 2021 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Objectives: Insulin-like growth factor-1 (IGF-1) and bone morphogenetic protein 2 (BMP-2) both promote osteogenesis of bone marrow mesenchymal stem cells (BMSCs). IGF-1C, the C domain peptide of IGF-1, and P24, a BMP-2-derived peptide, both have similar biological activities as their parent growth factors. This study aimed to investigate the effects and mechanisms of polypeptides IGF-1C and P24 on the osteogenic differentiation of BMSCs., Methods: The optimum concentrations of IGF-IC and P24 were explored. The effects of the two polypeptides on BMSC proliferation and osteogenic differentiation were examined using a CCK-8 assay, flow cytometry, alkaline phosphatase (ALP) staining, ALP activity assay, alizarin red S staining, qPCR, and Western blotting. In addition, specific pathway inhibitors were utilized to explore whether the p38 and JNK pathways were involved in this process., Results: The optimal concentration of both polypeptides was 50 μg/ml. IGF-1C and P24 synergistically promoted BMSC proliferation, increased ALP activity and calcified nodule formation, upregulated the mRNA and protein levels of Osx, Runx2, Ocn, Opn, and Col1a1, and improved the phosphorylation levels of p38 and JNK proteins. Inhibition of the pathways significantly reduced p38 and JNK activation and blocked Runx2 expression while inhibiting ALP activity and calcified nodule formation., Conclusions: These findings suggest that IGF-1C and P24 synergistically promote the osteogenesis of BMSCs through activation of the p38 and JNK signaling pathways., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Accumulating evidence shows that physical exercise has a positive effect on the release of neurotrophic factors and myokines. However, evidence regarding the optimal type of physical exercise for these release is still lacking. The aim of this study was to assess the acute and chronic effects of open-skill exercise (OSE) compared to closed-skill exercise (CSE) on serum and plasma levels of brain derived neurotrophic factor (BDNF S , BDNF P ), and serum levels of insulin like growth factor 1 (IGF-1), and interleukin 6 (IL-6) in healthy older adults., Methods: To investigate acute effects, thirty-eight participants were randomly assigned to either an intervention (badminton (aOSE) and bicycling (aCSE), n  = 24, 65.83 ± 5.98 years) or control group (reading (CG), n  = 14, 67.07 ± 2.37 years). Blood samples were taken immediately before and 5 min after each condition. During each condition, heart rate was monitored. The mean heart rate of aOSE and aCSE were equivalent (65 ± 5% of heart rate reserve). In a subsequent 12-week training-intervention, twenty-two participants were randomly assigned to either a sport-games (cOSE, n  = 6, 64.50 ± 6.32) or a strength-endurance training (cCSE, n  = 9, 64.89 ± 3.51) group to assess for chronic effects. Training intensity for both groups was adjusted to a subjective perceived exertion using the CR-10 scale (value 7). Blood samples were taken within one day after the training-intervention., Results: BDNF S , BDNF P , IGF-1, and IL-6 levels increased after a single exercise session of 30 min. After 12 weeks of training BDNF S and IL-6 levels were elevated, whereas IGF-1 levels were reduced in both groups. However, only in the cOSE group these changes were significant. We could not find any significant differences between the exercise types., Conclusion: Our results indicate that both exercise types are efficient to acutely increase BDNF S , BDNF P , IGF-1 and IL-6 serum levels in healthy older adults. Additionally, our results tend to support that OSE is more effective for improving basal BDNF S levels after 12 weeks of training., (© 2021. The Author(s).)

Background: Chemotherapy-induced peripheral neuropathy (CIPN) is a common and intractable complication in chemotherapy-receiving patients. Insulin-like growth factor-1 (IGF-1) is a popular neurotrophin with various functions, such as maintaining neuronal survival and synaptic functioning in the central nervous system. Therefore, we hypothesized that the IGF-1 signaling pathway could be a candidate target for treating CIPN., Methods: We established the CIPN model by injecting mice intraperitoneally with oxaliplatin and assessed IGF-1 protein expression, its receptor IGF1R, phospho-IGF1R (p-IGF1R), interleukin-17A (IL-17A), tumor necrosis factor-α (TNF-α), and calcitonin gene-related peptide (CGRP) in the lumbar spinal cord with Western blot and immunofluorescence. To examine the effect of IGF-1 signaling on CIPN, we injected mice intrathecally or intraperitoneally with mouse recombinant IGF-1 (rIGF-1)., Results: IGF-1 protein expression decreased significantly in the spinal cord on D3 and D10 (the 3rd and 10th days after beginning oxaliplatin chemotherapy) and was co-localized with astrocytes primarily in the lumbar spinal cord, whereas IGF1R was predominantly expressed on neurons. Both intrathecally- and intraperitoneally-administered rIGF-1 relieved the chemotherapy-induced pain-like behavior and reduced IL-17A, TNF-α, and CGRP protein expressions in the spinal cord., Conclusion: Our results indicate a vital role for IGF-1 signaling in CIPN. Targeting IGF-1 signaling could be a potent therapeutic strategy for treating CIPN in clinical settings., (Copyright © 2021 Elsevier Inc. All rights reserved.)

In skeletal-muscle regeneration, it is critical to promote efferocytosis of immune cells and differentiation of satellite cells/postnatal muscle stem cells at the damaged sites. With the optimized poloxamer 407 composition gelled at body temperature, the drugs can be delivered locally. The purpose of this study is to develop a topical injection therapeutic agent for muscle regeneration, sarcopenia, and cachexia. Herein, we construct an injectable, in situ hydrogel system consisting of CD146, IGF-1, collagen I/III, and poloxamer 407, termed CIC gel. The secreted CD146 then binds to VEGFR2 on the muscle surface and effectively induces efferocytosis of neutrophils and macrophages. IGF-1 promotes satellite cell differentiation, and biocompatible collagen evades immune responses of the CIC gel. Consequently, these combined molecules activate muscle regeneration via autophagy and suppress muscle inflammation and apoptosis. Conclusively, we provide an applicable concept of the myogenesis-activating protein formulation, broadening the thermoreversible hydrogel to protein therapeutics for damaged muscle recovery.

Jolkinolide B (JB) is a bioactive diterpenoid, isolated from the root of Euphorbia fischeriana Steud, and has been reported to have anti-tumor and anti-inflammation function by regulation of cell migration, invasion, apoptosis, and cell cycle. We aimed to evaluate the effect of JB on laryngeal cancer cells. Human normal larynx epithelial (HBE) cells and cancer cell lines TU212, TU177, and Hep-2 were cultured; MTT assay was used to assess cell proliferation. LY294002 (a PI3K/Akt inhibitor) and IGF-1 (a PI3K/Akt activator) were employed to investigate the expression of PI3K/Akt pathway. Cell migration and invasion activities were detected by scratch wound healing and transwell assay, respectively. Flow cytometry assay was used to assess cell apoptosis. The expression levels of proteins were assessed by immunofluorescence and Western blotting assay. JB inhibited TU212, TU177, and Hep-2 cell viability with an IC 50 value of 54.57 ± 0.53 μg/mL, 44.82 ± 0.32 μg/mL, and 49.63 ± 0.47 μg/mL, respectively. Compared with control group, the proliferation, migration, and invasion of cells significantly decreased after JB and LY294002 treatment, while cell apoptosis increased. In IGF-1 group, the results were opposite compared to the JB and LY294002 groups. Western blotting results showed that JB and LY294002 treatment significantly inhibited the levels of Bcl-2, p-PI3K, and p-Akt while the levels of Bax, cleaved caspase-3, and PTEN protein significantly increased. Our study suggested that JB exhibits an inhibition effect on laryngeal cancer cell growth in vitro., (© 2021. The Society for In Vitro Biology.)

This study was designed to examine the effects of seminal insulin-like growth factor-1 (IGF-1) supplementation on structural and functional properties of buffalo sperm post cryopreservation. Semen ejaculates from buffalo bulls (n = 6) were proportioned into four aliquots and diluted with egg yolk-based extender. Prior to equilibration, IGF-1 was added to extender as four treatments: group IGF0 (no supplementation), IGF150 (150 ng/mL), IGF250 (250 ng/mL) and IGF350 (350 ng/mL). The extended semen was transferred into 0.25 mL mini-straws, equilibrated (4 °C at 4 h), and cryopreserved. Total sperm motility was greater (P < 0.05) when there was the IGF150 treatment compared with values for other groups. Furthermore, with the IGF150 treatment there was the least and greatest (P < 0.05) mitochondrial superoxide status and membrane potential, respectively. Similarly, with the IGF150 treatment there was a greater (P < 0.05) sperm membrane integrity with a lesser (P < 0.05) calcium status compared to values for the other groups. In conclusion, seminal IGF-1 supplementation affects the structural and functional properties of buffalo sperm following cryopreservation., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Objective: IGF-I and branched-chain amino acids have been reported to promote muscle hypertrophy via the stimulation of protein synthesis. Sestrin2, the function of which is regulated by leucine, has been reported to attenuate the activity of the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) that stimulates protein synthesis. The objective of this study was to examine whether IGF-I modulates Sestrin2 abundance and to clarify the involvement of Sestrin2 in the effect of IGF-I and leucine on mTROC1., Design: C2C12 and L6 myocytes were stimulated by leucine (1 mM) with or without pretreatment with IGF-I (100 ng/mL). Phosphorylation of p70 S6 kinase (S6K) and 4E-binding protein 1 (4E-BP1), both of which are targets of the mTORC1, was examined by western blotting. Effects of Sestrin2 small interfering RNA (siRNA) on the actions of leucine and IGF-I were examined. Sestrin2 mRNA and protein levels were also determined after Sestrin2 siRNA., Results: Leucine increased the phosphorylation of S6K and 4E-BP1 in a dose-dependent manner. Pretreatment with IGF-I for 5 h further increased the stimulatory effect of leucine on the phosphorylation of S6K and 4E-BP1 in C2C12 cells. IGF-I increased Sestrin2 protein and messenger RNA levels. Sestrin2 siRNA increased or tended to increase basal phosphorylation of 4E-BP1 and decreased the leucine-induced phosphorylation in C2C12 and L6 cells, in particular after IGF-I treatment, suggesting the involvement of Sestrin2 in the action of leucine and IGF-I. The net increase in leucine-induced 4E-BP1 phosphorylation appeared to be attenuated by Sestrin2 siRNA. Likewise, Sestrin2 siRNA attenuated leucine-induced S6K phosphorylation in L6 cells. However, Sestrin2 siRNA did not influence leucine-induced S6K phosphorylation in C2C12 cells., Conclusions: IGF-I and leucine cooperatively increased mTORC1 activity in C2C12 cells. IGF-I increased Sestrin2. Sestrin2 siRNA experiments showed that Sestrin2 was involved in the effect of leucine and IGF-I on mTORC1 activity in C2C12 and L6 cells, and suggested that increased Sestrin2 by IGF-I pretreatment might play a role in enhancing the effect of leucine on mTORC1., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

M2‑like tumour‑associated macrophages (TAMs) have been demonstrated to promote the growth of anaplastic thyroid carcinoma (ATC). However, the underlying mechanism of M2‑like TAMs in ATC remains unclear. Thus, in the present study, the role and mechanism of M2‑like TAMs in ATC were investigated. M2‑like TAMs were induced by treatment with PMA, plus IL‑4 and IL‑13, and identified by flow cytometry. Transwell and sphere formation assays were applied to assess the invasion and stemness of ATC cells. The expression levels of insulin‑like growth factor (IGF)‑1 and IGF‑2 were examined by ELISA and reverse transcription‑quantitative PCR. Proteins related to the epithelial‑mesenchymal transition (EMT), stemness and the PI3K/AKT/mTOR pathway were examined via western blotting. Immunohistochemistry (IHC) was used to detect the expression of the M2‑like TAM markers CD68 and CD206 in ATC tissues and thyroid adenoma tissues. It was found that treatment with PMA plus IL‑4 and IL‑13 successfully induced M2‑like TAMs. Following co‑culture with M2‑like TAMs, the invasive ability and stemness of ATC cells were significantly increased. The expression levels of the EMT‑related markers N‑cadherin and Vimentin, the stemness‑related markers Oct4, Sox2 and CD133, and the insulin receptor (IR)‑A/IGF1 receptor (IGF1R) were markedly upregulated, whereas E‑cadherin expression was significantly decreased. In addition, the production of IGF‑1 and IGF‑2 was significantly increased. Of note, exogenous IGF‑1/IGF‑2 promoted the invasion and stemness of C643 cells, whereas blocking IGF‑1 and IGF‑2 inhibited metastasis and stemness by repressing IR‑A/IGF‑1R‑mediated PI3K/AKT/mTOR signalling in the co‑culture system. IHC results showed that the expression of CD68 and CD206 was obviously increased in ATC tissues. To conclude, M2‑like TAMs accelerated the metastasis and increased the stemness of ATC cells, and the underlying mechanism may be related to the section of IGF by M2‑like TAMs, which activates the IR‑A/IGF1R‑mediated PI3K/AKT/mTOR signalling pathway.

Osteoarthritis (OA) is characterized by pain and declining gait function associated with degeneration of cartilage. A severe hypoxic environment occurs due to tissue injury in the joint cavity and may aggravate the development of OA. In this study, the effects of severe hypoxia and treatment with mechano growth factor (MGF) E peptide on metabolism of the extracellular matrix (ECM) during the progression of OA were determined. The results showed that cell viability, cell proliferation, and type II collagen expression in chondrocytes were significantly inhibited by cobalt chloride (CoCl 2 )-simulated severe hypoxia, whereas cell apoptosis and expression levels of hypoxia inducible factor 1 alpha, type I collagen, and matrix metalloproteinases 1/13 were clearly induced. Pretreatment with MGF E peptide reduced the abovementioned adverse effects induced by CoCl 2 -simulated severe hypoxia in chondrocytes. Pretreatment also upregulated the proliferation of chondrocytes under severe hypoxia through the PI3K-Akt and MEK-ERK1/2 signaling pathways. In a rat model of monosodium iodoacetate (MIA)-induced OA. MIA treatment induced tissue necrosis and cartilage degeneration, and histological score was significantly decreased. The levels of type II collagen and aggrecan were reduced after MIA treatment for 4 or 6 weeks, and abnormal distribution of ECM occurred in the inner epicondyle after 6 weeks. MGF E peptide also reduced the progression of MIA-induced OA by retarding cartilage degeneration, upregulating type II collagen synthesis, and improving ECM distribution after 4 or 6 weeks. Our findings suggest that MGF attenuates the progression of OA, and thus may be applied for the treatment of OA in the clinic., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The nuclear estrogen‑related receptor‑α (ERRα) is an orphan receptor that has been identified as a transcriptional factor. Peroxisome proliferator‑activated receptor‑γ (PPARγ) coactivator‑1‑α (PGC‑1α) and PPARγ coactivator‑1‑β (PGC‑1β) act as the co‑activators of ERRα. Our previous study reported that activated ERRα promoted the invasion and proliferation of gallbladder cancer cells by promoting PI3K/AKT phosphorylation. Therefore, the aim of the current study was to investigate whether PI3K/AKT phosphorylation could enhance ERRα activity in a positive feedback loop. LY294002 and insulin‑like growth factor I (IGF‑I) were used to inhibit and promote PI3K/AKT phosphorylation, respectively. A 3X ERE‑TATA luciferase reporter was used to measure ERRα activity. The present study found that LY294002 inhibited PI3K/AKT phosphorylation, decreased the proliferation and invasion of NOZ cells and suppressed the activity of ERRα. Conversely, IGF‑I induced PI3K/AKT phosphorylation, promoted the proliferation and invasion of NOZ cells and enhanced the activity of ERRα. The protein expression levels of PGC‑1α and PGC‑1β were elevated and reduced by IGF‑I and LY294002, respectively. Moreover, knockdown of PGC‑1α and PGC‑1β antagonized ERRα activation, which was enhanced by PI3K/AKT phosphorylation. Taken together, the present study demonstrated that PI3K/AKT phosphorylation triggered ERRα by upregulating the expression levels of PGC‑1α and PGC‑1β in NOZ cells.

Recently, mesenchymal stem cells (MSCs) have been the most explored cells for cell therapy for osteoarthritis (OA) that can be obtained from various sources. Synovial membrane MSCs (SMMSCs) provide best potential for OA therapy, however they are not widely explored. Conditioned medium of SMMSCs (SMMSCs-CM) rich in growth factors and cytokines can inhibit apoptosis and increase chondrocytes cell proliferation. The aim of the present study was to determine growth factors content in SMMSCs-CM as well as the chondrogenic and chondroprotective markers expression in OA model after insulin-like growth factor (IGF)1-induced and non-induced SMMSCs-CM treatments. Chondrocyte cell line (CHON002) was induced by IL1β as OA model (CHON002 with IL1β (IL1β-CHON002)) and treated with SMMSCs-CM with or without IGF1 induction to determine its effectiveness in repairing OA cells model. ELISA was used to assay BMP2, fibroblast growth factor 18 (FGF18) and transforming growth factor (TGF) β1 (TGFβ1) levels in SMMSCs-CM, matrix metalloproteinase (MMP) 13 (MMP13) and a disintegrin and metalloproteinase with thrombospondin motif 4 (ADAMTS4) levels in OA cells model treated with SMMSCs-CM. RT-qPCR analyses were used to investigate the gene expression of SOX9, COL2, and COL10. CM from SMMSCs cultured and induced by IGF1 150 ng/mL was the most effective concentration for increasing the content of growth factor markers of SMMSCs-CM, which had successfully increased negative cartilage hypertrophy markers (SOX9 and COL2) and reduced hypertrophy markers (COL10, MMP13, and ADAMTS4). Preconditioning with IGF1 has better and very significant results in lowering MMP13 and ADAMTS4 levels. The present study supports IGF1 pre-conditioned SMMSCs-CM to develop a new therapeutic approach in OA improvement through its chondrogenic and chondroprotective roles., (© 2021 The Author(s).)

Development of resistance to therapy in ovarian cancer is a major hinderance for therapeutic efficacy; however, new mechanisms of the resistance remain to be elucidated. NADPH oxidase 4 (NOX4) is responsible for higher NADPH activity to increase reactive oxygen species (ROS) production. In this study, we showed that higher levels of NOX4 were detected in a large portion of human ovarian cancer samples. To understand the molecular mechanism of the NOX4 upregulation, we showed that NOX4 expression was induced by HIF-1α and growth factor such as IGF-1. Furthermore, our results indicated that NOX4 played a pivotal role in chemotherapy and radiotherapy resistance in ovarian cancer cells. We also demonstrated that NOX4 knockdown increased sensitivity of targeted therapy and radiotherapy through decreased expression of HER3 (ERBB3) and NF-κB p65. Taken together, we identified a new HIF-1α/NOX4 signal pathway which induced drug and radiation resistance in ovarian cancer. The finding may provide a new option to overcome the therapeutic resistance of ovarian cancer in the future.

Aberrant signaling through insulin (Ins) and insulin-like growth factor I (IGF1) receptors contribute to the risk and advancement of many cancer types by activating cell survival cascades. Similarities between these pathways have thus far prevented the development of pharmacological interventions that specifically target either Ins or IGF1 signaling. To identify differences in early Ins and IGF1 signaling mechanisms, we developed a dual receptor (IGF1R & InsR) computational response model. The model suggested that ribosomal protein S6 kinase (RPS6K) plays a critical role in regulating MAPK and Akt activation levels in response to Ins and IGF1 stimulation. As predicted, perturbing RPS6K kinase activity led to an increased Akt activation with Ins stimulation compared to IGF1 stimulation. Being able to discern differential downstream signaling, we can explore improved anti-IGF1R cancer therapies by eliminating the emergence of compensation mechanisms without disrupting InsR signaling., Competing Interests: The authors have declared that no competing interests exist.

The application of insulin-like growth factor 1 (IGF-1) to the round window membrane (RWM) is an emerging treatment for inner ear diseases. RWM permeability is the key factor for efficient IGF-1 delivery. Ultrasound microbubbles (USMBs) can increase drug permeation through the RWM. In the present study, the enhancing effect of USMBs on the efficacy of IGF-1 application and the treatment effect of USMB-mediated IGF-1 delivery for noise-induced hearing loss (NIHL) were investigated. Forty-seven guinea pigs were assigned to three groups: the USM group, which received local application of recombinant human IGF-1 (rhIGF-1, 10 µg/µL) following application of USMBs to the RWM; the RWS group, which received IGF-1 application alone; and the saline-treated group. The perilymphatic concentration of rhIGF-1 in the USM group was 1.95- and 1.67- fold of that in the RWS group, 2 and 24 h after treatment, respectively. After 5 h of 118 dB SPL noise exposure, the USM group had the lowest threshold shift in auditory brainstem response, least loss of cochlear outer hair cells, and least reduction in the number of synaptic ribbons on postexposure day 28 among the three groups. The combination of USMB and IGF-1 led to a better therapeutic response to NIHL. Two hours after treatment, the USM group had significantly higher levels of Akt1 and Mapk3 gene expression than the other two groups. The most intense immunostaining for phosphor-AKT and phospho-ERK1/2 was detected in the cochlea in the USM group. These results suggested that USMB can be applied to enhance the efficacy of IGF-1 therapy in the treatment of inner ear diseases.

The goals of this study are to develop a high purity patented silk fibroin (SF) film and test its suitability to be used as a slow-release delivery for insulin-like growth factor-1 (IGF-1). The release rate of the SF film delivering IGF-1 followed zero-order kinetics as determined via the Ritger and Peppas equation. The release rate constant was identified as 0.11, 0.23, and 0.09% h -1 at 37 °C for SF films loaded with 0.65, 6.5, and 65 pmol IGF-1, respectively. More importantly, the IGF-1 activity was preserved for more than 30 days when complexed with the SF film. We show that the IGF-1-loaded SF films significantly accelerated wound healing in vitro (BALB/3T3) and in vivo (diabetic mice), compared with wounds treated with free IGF-1 and an IGF-1-loaded hydrocolloid dressing. This was evidenced by a six-fold increase in the granulation tissue area in the IGF-1-loaded SF film treatment group compared to that of the PBS control group. Western blotting analysis also demonstrated that IGF-1 receptor (IGF1R) phosphorylation in diabetic wounds increased more significantly in the IGF-1-loaded SF films group than in other experimental groups. Our results suggest that IGF-1 sustained release from SF films promotes wound healing through continuously activating the IGF1R pathway, leading to the enhancement of both wound re-epithelialization and granulation tissue formation in diabetic mice. Collectively, these data indicate that SF films have considerable potential to be used as a wound dressing material for long-term IGF-1 delivery for diabetic wound therapy.

His-tRNA synthetase (HARS) is targeted by autoantibodies in chronic and acute inflammatory anti-Jo-1-positive antisynthetase syndrome. The extensive activation and migration of immune cells into lung and muscle are associated with interstitial lung disease, myositis, and morbidity. It is unknown whether the sequestration of HARS is an epiphenomenon or plays a causal role in the disease. Here, we show that HARS circulates in healthy individuals, but it is largely undetectable in the serum of anti-Jo-1-positive antisynthetase syndrome patients. In cultured primary human skeletal muscle myoblasts (HSkMC), HARS is released in increasing amounts during their differentiation into myotubes. We further show that HARS regulates immune cell engagement and inhibits CD4 + and CD8 + T-cell activation. In mouse and rodent models of acute inflammatory diseases, HARS administration downregulates immune activation. In contrast, neutralization of extracellular HARS by high-titer antibody responses during tissue injury increases susceptibility to immune attack, similar to what is seen in humans with anti-Jo-1-positive disease. Collectively, these data suggest that extracellular HARS is homeostatic in normal subjects, and its sequestration contributes to the morbidity of the anti-Jo-1-positive antisynthetase syndrome.

Inflammation contributes to mitochondrial dysfunction and neuronal apoptosis. The aim of this study was to determine whether insulin-like growth factor-1 (IGF-1) alleviates mitochondrial apoptosis in lipopolysaccharide (LPS)-treated PC-12 cells, and to further explore the mechanism involved. Prepared PC-12 cells were treated with IGF-1, Mdivi-1 (DRP1 blocker), LY294002 (PI3K blocker), betulinic acid (NF-κB activator) or their combinations. Mitochondrial membrane potential and ATP generation were then measured to assess mitochondrial function. The rate of apoptosis was determined using flow cytometry. The expression of several apoptosis proteins (i.e. Bax, cleaved caspase-9 and cleaved caspase-3) and signaling proteins (i.e. p-GSK3β, NF-κB and NLRP3) was measured using western blotting. Compared with the control cells, the LPS-treated cells showed evidence of mitochondrial dysfunction, increased apoptosis and upregulation of apoptosis proteins, which were significantly alleviated by Mdivi-1. These findings indicate that neuronal apoptosis was activated partly through the mitochondrial pathway. IGF-1 treatment inhibited mitochondrial apoptosis in a dose-dependent manner in the LPS-treated cells. The reagent also increased the expression of p-GSK3β and decreased the expression of NF-κB and NLRP3. Both LY294002 and betulinic acid reversed the protective effect of IGF-1. In addition, LY294002 affected the expression of the three signaling proteins, while betulinic acid only affected the expression of NF-κB and NLRP3. These findings indicated a GSK3β/NF-κB/NLRP3 signaling pathway was existed and was involved in the protective mechanism of IGF-1. In conclusion, IGF-1 alleviated mitochondrial apoptosis through GSK3β/NF-κB/NLRP3 signaling pathway in LPS-treated PC-12 cells.