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Porphyromonas gingivalis is a gram-negative anaerobic bacterium linked to periodontal disease. Remarkably, P. gingivalis thrives in an inflamed environment rich in activated neutrophils. Toll-like receptor 2 (TLR2) recognition is required for P. gingivalis to evade innate immune killing; however, the mechanisms through which P. gingivalis uncouples host inflammation from bactericidal activity are only partially known. Since integrin activation and alternative signaling are implicated in P. gingivalis TLR2-mediated immune escape, we explored the role of CD47, a widely expressed integrin-associated protein known to suppress phagocytosis and implicated as an interacting partner with other innate immune receptors. We found that CD47 associates with TLR2, and blocking CD47 leads to decreased intracellular P. gingivalis survival in macrophages in a manner dependent on the bacterial major fimbria. In vivo, CD47 knock-out mice cleared P. gingivalis more efficiently than wild-type mice. Next, we found increased expression and secretion of the CD47 ligand thrombospondin-1 (TSP-1) following P. gingivalis infection. Secreted TSP-1 broadly protected P. gingivalis and other periodontitis-associated bacterial species from neutrophil bactericidal activity. Therefore, CD47-TLR2 cosignaling in response to P. gingivalis induces TSP-1 that in turn suppresses neutrophil activity, an effect that can explain how species such as P. gingivalis survive in an inflamed environment and cause dysbiosis. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is a degenerative eye disease leading to central vision loss and is characterized by dysregulated autophagy of the retinal pigment epithelium (RPE) layer. Recent studies have suggested that rho-associated protein kinase (ROCK) inhibitors may enhance autophagy in neurodegenerative diseases and promote the survival of RPE cells. This study investigated the effect of ROCK inhibitors on autophagy gene expression and autophagic vacuole formation in a human RPE (ARPE-19) cell line. The highly selective and potent ROCK inhibitor Y-39983 enhanced the expression of autophagy genes in ARPE-19 cells and increased autophagic vacuole formation. A proteomic analysis using mass spectrometry was performed to further characterize the effects of ROCK inhibition at the protein level. Y-39983 downregulated thrombospondin-1 (THBS1), and suppression of THBS1 in ARPE-19 cells resulted in an increase in autophagic vacuole formation. Our data showed that ROCK inhibitor-induced autophagy was mediated by THBS1 downregulation. We identified ROCK and THBS1 as potential novel therapeutic targets in AMD. [ABSTRACT FROM AUTHOR]

Abstract Aims/Introduction We investigated the relationship of circulating TSP‐1 mRNA and miR‐194 with diabetic kidney disease’s degree. Materials and Methods We enrolled 167 hospitalized type 2 diabetes patients in the endocrinology department. Patients were split into three groups according to urinary microalbumin: A, B and C. The control group comprised healthy outpatients (n = 163). The quantities of microribonucleic acid (miR)‐194 and thrombospondin‐1 (TSP‐1) messenger ribonucleic acid (mRNA) in the participants’ circulation were measured using a quantitative real‐time polymerase chain reaction. Results Circulating TSP‐1 mRNA (P = 0.024) and miR‐194 (P = 0.029) expressions significantly increased in type 2 diabetes patients. Circulating TSP‐1 mRNA (P = 0.040) and miR‐194 (P = 0.007) expression levels differed significantly among the three groups; circulating TSP‐1 mRNA expression increased with urinary microalbumin. However, miR‐194 declined in group B and increased in group C. Circulating TSP‐1 mRNA was positively correlated with cystatin‐c (r = 0.281; P = 0.021) and microalbumin/creatinine ratio (UmALB/Cr; r = 0.317; P = 0.009); miR‐194 was positively correlated with UmALB/Cr (r = 0.405; P = 0.003). Stepwise multivariate linear regression analysis showed cystatin‐c (β = 0.578; P = 0.021) and UmALB/Cr (β = 0.001; P = 0.009) as independent factors for TSP‐1 mRNA; UmALB/Cr (β = 0.005; P = 0.028) as an independent factor for miR194. Areas under the curve for circulating TSP‐1 mRNA and miR194 were 0.756 (95% confidence interval 0.620–0.893; sensitivity 0.69 and specificity 0.71, P

Background: Hereditary Hemorrhagic Telangiectasia (HHT) is a genetic disorder leading to frequent bleeding in several organs. As HHT diagnosis is demanding and depends on clinical criteria, liquid biopsy would be beneficial. Exosomes from biofluids are nano-sized vesicles for intercellular communication. Their cargo and characteristics represent biomarkers for many diseases. Here, exosomes of HHT patients were examined regarding their biosignature. Methods: Exosomes were isolated from the plasma of 20 HHT patients and 17 healthy donors (HDs). The total exosomal protein was quantified, and specific proteins were analyzed using Western blot and antibody arrays. Human umbilical vein endothelial cells (HUVECs) co-incubated with exosomes were functionally examined via immunofluorescence, proliferation, and scratch assay. Results: The levels of the angiogenesis-regulating protein Thrombospondin-1 were significantly higher in HHT compared to HD exosomes. Among HHT, but not HD exosomes, a negative correlation between total exosomal protein and soluble Endoglin (sENG) levels was found. Other exosomal proteins (ALK1, ALK5) and the particle concentration significantly correlated with disease severity parameters (total consultations/interventions, epistaxis severity score) in HHT patients. Functionally, HUVECs were able to internalize both HD and HHT exosomes, inducing a similar change in the F-Actin structure and a reduction in migration and proliferation. Conclusions: This study provided first insights into the protein cargo and function of HHT-derived exosomes. The data indicate changes in sENG secretion via exosomes and reveal exosomal Thrombospondin-1 as a potential biomarker for HHT. Several exosomal characteristics were pointed out as potential liquid biomarkers for disease severity, revealing a possible new way of diagnosis and prognosis of HHT. [ABSTRACT FROM AUTHOR]

Aims/Introduction: We investigated the relationship of circulating TSP‐1 mRNA and miR‐194 with diabetic kidney disease's degree. Materials and Methods: We enrolled 167 hospitalized type 2 diabetes patients in the endocrinology department. Patients were split into three groups according to urinary microalbumin: A, B and C. The control group comprised healthy outpatients (n = 163). The quantities of microribonucleic acid (miR)‐194 and thrombospondin‐1 (TSP‐1) messenger ribonucleic acid (mRNA) in the participants' circulation were measured using a quantitative real‐time polymerase chain reaction. Results: Circulating TSP‐1 mRNA (P = 0.024) and miR‐194 (P = 0.029) expressions significantly increased in type 2 diabetes patients. Circulating TSP‐1 mRNA (P = 0.040) and miR‐194 (P = 0.007) expression levels differed significantly among the three groups; circulating TSP‐1 mRNA expression increased with urinary microalbumin. However, miR‐194 declined in group B and increased in group C. Circulating TSP‐1 mRNA was positively correlated with cystatin‐c (r = 0.281; P = 0.021) and microalbumin/creatinine ratio (UmALB/Cr; r = 0.317; P = 0.009); miR‐194 was positively correlated with UmALB/Cr (r = 0.405; P = 0.003). Stepwise multivariate linear regression analysis showed cystatin‐c (β = 0.578; P = 0.021) and UmALB/Cr (β = 0.001; P = 0.009) as independent factors for TSP‐1 mRNA; UmALB/Cr (β = 0.005; P = 0.028) as an independent factor for miR194. Areas under the curve for circulating TSP‐1 mRNA and miR194 were 0.756 (95% confidence interval 0.620–0.893; sensitivity 0.69 and specificity 0.71, P < 0.01) and 0.584 (95% confidence interval 0.421–0.748; sensitivity 0.54 and specificity 0.52, P < 0.01), respectively. Conclusions: Circulating TSP‐1 mRNA and miR‐194 expressions significantly increased in type 2 diabetes patients. The microalbumin group had lower levels of miR‐194 (a risk factor that is valuable for type 2 diabetes kidney disease evaluation). [ABSTRACT FROM AUTHOR]

Focal segmental glomerulosclerosis (FSGS), a common cause of primary glomerulonephritis, has a poor prognosis and is pathologically featured by tubulointerstitial injury. Thrombospondin-1 (TSP-1) is an extracellular matrix protein that acts in combination with different receptors in the kidney. Here, we analyzed the tubular expression of TSP-1 and its receptor integrin b3 (ITGB3) in FSGS. Previously the renal interstitial chip analysis of FSGS patients with tubular interstitial injury showed that the expression of TSP-1 and ITGB3 were upregulated. We found that the expression of TSP-1 and ITGB3 increased in the tubular cells of FSGS patients. The plasma level of TSP-1 increased and was correlated to the degree of tubulointerstitial lesions in FSGS patients. TSP-1/ ITGB3 signaling induced renal tubular injury in HK-2 cells exposure to bovine serum albumin and the adriamycin (ADR)- induced nephropathy model. THBS1 KO ameliorated tubular injury and renal fibrosis in ADR-treated mice. THBS1 knockdown decreased the expression of KIM-1 and caspase 3 in the HK-2 cells treated with bovine serum albumin, while THBS1 overexpression could induce tubular injury. In vivo, we identified cyclo-RGDfK as an agent to block the binding of TSP-1 to ITGB3. Cyclo-RGDfK treatment could alleviate ADR-induced renal tubular injury and interstitial fibrosis in mice. Moreover, TSP-1 and ITGB3 were colocalized in tubular cells of FSGS patients and ADR-treated mice. Taken together, our data showed that TSP-1/ITGB3 signaling contributed to the development of renal tubulointerstitial injury in FSGS, potentially identifying a new therapeutic target for FSGS. [ABSTRACT FROM AUTHOR]

Background: Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder, the etiology of which has not been clearly determined yet. There is increasing evidence that synaptic and dendritic changes are involved in the etiology of ASD. The aim of this study is to determine whether serum Thrombospondin-1 and Thrombospondin-2 differ between ASD patients and healthy controls. This study also investigates possible correlations between clinical symptomatology of ASD and serum Thrombospondin-1 and Thrombospondin-2 levels. Method: A total of 44 children with ASD and 21 healthy controls under 6 years of age were included in the study. Symptom severity and behavioral problems among children with ASD were evaluated by using Childhood Autism Rating Scale and Abnormal Behavior Checklist. Serum levels of Thrombospondin-1 and Thrombospondin-2 were measured by using commercial enzyme-linked immunosorbent assay kits. Result: No statistically significant differences were found between the two groups in terms of serum Thrombospondin-1 and Thrombospondin-2 levels. In addition, no correlation was determined between Thrombospondin-2 levels and clinical symptomatology and severity of ASD. However, the Thrombospondin-1 level was found to negatively correlated with the total score of Childhood Autism Rating Scale, inappropriate speech and stereotype subscale scores of Aberrant Behavior Checklist scale. Conclusion: Thrombospondin-1 might have a potential role in the etiopathogenesis of ASD. Further studies are required to clearly elucidate the association between Trombospondin-1 and ASD. [ABSTRACT FROM AUTHOR]

Purpose of Review: Fibromyalgia syndrome (FMS) is a disease of unknown pathophysiology, with the diagnosis being based on a set of clinical criteria. Proteomic analysis can provide significant biological information for the pathophysiology of the disease but may also reveal biomarkers for diagnosis or therapeutic targets. The present systematic review aims to synthesize the evidence regarding the proteome of adult patients with FMS using data from observational studies. Recent Findings: An extensive literature search was conducted in MEDLINE/PubMed, CENTRAL, and clinicaltrials.gov from inception until November 2022. The study protocol was published in OSF. Two independent reviewers evaluated the studies and extracted data. The quality of studies was assessed using the modified Newcastle–Ottawa scale adjusted for proteomic research. Ten studies fulfilled the protocol criteria, identifying 3328 proteins, 145 of which were differentially expressed among patients with FMS against controls. The proteins were identified in plasma, serum, cerebrospinal fluid, and saliva samples. The control groups included healthy individuals and patients with pain (inflammatory and non-inflammatory). Summary: The most important proteins identified involved transferrin, α-, β-, and γ-fibrinogen chains, profilin-1, transaldolase, PGAM1, apolipoprotein-C3, complement C4A and C1QC, immunoglobin parts, and acute phase reactants. Weak correlations were observed between proteins and pain sensation, or quality of life scales, apart from the association of transferrin and a2-macroglobulin with moderate-to-severe pain sensation. The quality of included studies was moderate-to-good. FMS appears to be related to protein dysregulation in the complement and coagulation cascades and the metabolism of iron. Several proteins may be dysregulated due to the excessive oxidative stress response. [ABSTRACT FROM AUTHOR]

Background: Fine particulate matter (PM2.5) induces ocular surface toxicity through pyroptosis, oxidative stress, autophagy, and inflammatory responses. However, the precise molecular pathways through which PM2.5 causes corneal damage remain unclear. This study aims to investigate the underlying mechanisms by exposing human corneal epithelial cells (HCECs) to PM2.5. Methods: After the morphology and chemical composition analysis of the PM samples, we conducted both in vivo and in vitro experiments to investigate PM2.5-induced corneal epithelial damage. We assessed corneal barrier function in HCECs using transepithelial electrical resistance (TEER) assays. To explore the molecular mechanisms of PM2.5-induced corneal epithelial damage, we performed whole-transcriptome resequencing, quantitative RT-PCR, and western blotting in vitro. In addition, we analyzed mouse corneas exposed to concentrated ambient PM2.5 through immunofluorescence staining to observe the resulting changes in corneal epithelial protein expression in vivo. Results: Our results showed significant impairment of corneal epithelial barrier function in PM2.5-treated HCECs, as indicated by decreased TEER values. The expression of thrombospondin-1 (THBS1) and claudin-1, both key factors for maintaining corneal epithelial barrier integrity, was markedly reduced at the gene and protein levels in both in vitro and in vivo PM2.5 exposure models. Moreover, the levels of tight junction-associated proteins, including occludin, zonula occludens-1 (ZO-1) and ZO-2, essential components of the corneal epithelial barrier, were significantly diminished in PM2.5-treated HCECs. Conclusion: PM2.5 exposure leads to corneal epithelium damage by disrupting tight junction proteins and THBS1 expression. These findings provide insight into potential pathways for PM2.5-induced ocular toxicity and underscore the need for protective strategies against such environmental pollutants.

Preeclampsia (PE) is considered as a disease of placental origin. However, the specific mechanism of placental abnormalities remains elusive. This study identified thrombospondin‐1 (THBS1) is downregulated in preeclamptic placentae and negatively correlated with blood pressure. Functional studies show that THBS1 knockdown inhibits proliferation, migration, and invasion and increases the cycle arrest and apoptosis rate of HTR8/SVneo cells. Importantly, THBS1 silencing induces necroptosis in HTR8/SVneo cells, accompanied by the release of damage‐associated molecular patterns (DAMPs). Necroptosis inhibitors necrostatin‐1 and GSK′872 restore the trophoblast survival while pan‐caspase inhibitor Z‐VAD‐FMK has no effect. Mechanistically, the results show that THBS1 interacts with transforming growth factor B‐activated kinase 1 (TAK1), which is a central modulator of necroptosis quiescence and affects its stability. Moreover, THBS1 silencing up‐regulates the expression of neuronal precursor cell‐expressed developmentally down‐regulated 4 (NEDD4), which acts as an E3 ligase of TAK1 and catalyzes K48‐linked ubiquitination of TAK1 in HTR8/SVneo cells. Besides, THBS1 attenuates PE phenotypes and improves the placental necroptosis in vivo. Taken together, the down‐regulation of THBS1 destabilizes TAK1 by activating NEDD4‐mediated, K48‐linked TAK1 ubiquitination and promotes necroptosis and DAMPs release in trophoblast cells, thus participating in the pathogenesis of PE. [ABSTRACT FROM AUTHOR]

[Display omitted] • First human trial comparing plasma TSP-1 and vWF after desmopressin vs LPS infusion • Systemic TSP-1 and vWF are increased rapidly after desmopressin stimulation • Plasma TSP-1 drops after LPS infusion, while circulating vWF shows a late rise • LPS (not desmopressin) triggers transient loss of leukocytes, platelets from blood • Cell loss from circulation in endotoxemia is not altered in TSP-1 knockout mice [ABSTRACT FROM AUTHOR]

Epilepsy is a neural network disorder caused by uncontrolled neuronal hyperexcitability induced by an imbalance between excitatory and inhibitory networks. Abnormal synaptogenesis plays a vital role in the formation of overexcited networks. Recent evidence has confirmed that thrombospondin-1 (TSP-1), mainly secreted by astrocytes, is a critical cytokine that regulates synaptogenesis during epileptogenesis. Furthermore, numerous studies have reported that TSP-1 is also involved in other processes, such as angiogenesis, neuroinflammation, and regulation of Ca2+ homeostasis, which are closely associated with the occurrence and development of epilepsy. In this review, we summarize the potential contributions of TSP-1 to epilepsy development. [ABSTRACT FROM AUTHOR]

Background: Thrombospondin-1 (THBS1) is a secretory adhesive glycoprotein involved in the progression of multiple malignancies, including breast cancer. However, the clinical significance and prognostic role of plasma THBS1 in breast cancer have yet to be clarified. Methods: Plasma THBS1 levels in 627 breast cancer patients were analyzed by enzyme-linked immunosorbent assay. Bone marrow blood was drawn from the anterior/posterior superior iliac spine to detect the presence of disseminated tumor cells (DTCs). The effects of plasma THBS1 on the clinicopathological characteristics and survival prediction of breast cancer patients were explored. Results: Plasma THBS1 did not correlate with overall survival, breast cancer-specific survival (BCSS), and distant disease-free survival (DDFS) in the entire breast cancer cohort. Notably, HER2-enriched patients with high-plasma THBS1 levels had significantly shorter BCSS (P = 0.027) and DDFS (P = 0.011) than those with low levels. Multivariate analyses revealed that plasma THBS1 was an independent prognostic marker of BCSS (P = 0.026) and DDFS (P = 0.007) in HER2-enriched patients. THBS1 levels were 24% higher in positive DTC patients than in negative DTC patients (P = 0.031), and high levels were significantly associated with poor BCSS in positive DTC patients (HR 2.08, 95% CI 1.17–3.71; P = 0.019). Moreover, high-plasma THBS1 levels were specifically associated with an increased occurrence of brain metastasis in HER2-enriched patients (P = 0.041). Conclusion: These findings suggest that plasma THBS1 may be serving as an unfavorable prognosis predictor for HER2-enriched breast cancer and justifies the need for further research. [ABSTRACT FROM AUTHOR]

Extramedullary erythropoiesis is not expected in healthy adult mice, but erythropoietic gene expression was elevated in lineage-depleted spleen cells from Cd47−/− mice. Expression of several genes associated with early stages of erythropoiesis was elevated in mice lacking CD47 or its signaling ligand thrombospondin-1, consistent with previous evidence that this signaling pathway inhibits expression of multipotent stem cell transcription factors in spleen. In contrast, cells expressing markers of committed erythroid progenitors were more abundant in Cd47−/− spleens but significantly depleted in Thbs1−/− spleens. Single-cell transcriptome and flow cytometry analyses indicated that loss of CD47 is associated with accumulation and increased proliferation in spleen of Ter119−CD34+ progenitors and Ter119+CD34− committed erythroid progenitors with elevated mRNA expression of Kit, Ermap, and Tfrc. Induction of committed erythroid precursors is consistent with the known function of CD47 to limit the phagocytic removal of aged erythrocytes. Conversely, loss of thrombospondin-1 delays the turnover of aged red blood cells, which may account for the suppression of committed erythroid precursors in Thbs1−/− spleens relative to basal levels in wild-type mice. In addition to defining a role for CD47 to limit extramedullary erythropoiesis, these studies reveal a thrombospondin-1-dependent basal level of extramedullary erythropoiesis in adult mouse spleen.

Abstract Aims/Introduction Thrombospondin‐1 (TSP‐1) participates in a series of physiological and pathological processes by binding to various receptors regulating cell proliferation, adhesion and apoptosis. Elevated circulating TSP‐1 is linked with diabetic vascular complications (DVC). This study aimed to determine the relationship between circulating TSP‐1 levels and DVC. Materials and Methods A comprehensive search of PubMed, Embase, Web of Science and CNKI databases was carried out. A meta‐analysis was carried out to compare circulating TSP‐1 levels between diabetes patients without vascular complications (DNVC), diabetes patients with DVC and non‐diabetes patients. The correlation between TSP‐1 and metabolic parameters was also analyzed. Subgroup analysis was carried out according to complication type, defined as diabetic retinopathy, diabetic nephropathy and diabetic cardiovascular disease (DCVD). Results A total of eight studies were included. Compared with non‐diabetes patients, diabetic patients, including DNVC and DVC, had significantly higher circulating TSP‐1 levels (standardized mean difference [SMD] 2.660, 95% CI 1.17–4.145, P = 0.000). DNVC had significantly higher circulating TSP‐1 levels than non‐diabetes patients (SMD 3.613, 95% CI 1.607–5.619, P = 0.000). DVC had significantly higher TSP‐1 levels than DNVC (SMD 0.568, 95% CI 0.100–1.036, P = 0.017). TSP‐1 was significantly positively correlated with fasting plasma glucose (overall Fisher's z = 0.696, 95% CI 0.559–0.833) and HbA1c (overall Fisher's z = 0.849, 95% CI 0.776–0.923). Conclusions Elevated circulating TSP‐1 levels are closely related to DVC, especially in diabetic nephropathy and diabetic cardiovascular disease. Circulating TSP‐1 detection might be helpful in the timely diagnosis and treatment of DVC.

Background and Purpose: Physiological angiogenesis and homeostasis of blood vessels is a complex process that is regulated at a high level by the balance between positive proteins such as follistatin-like factor-1 (FSTL-1) and negative proteins such as thrombospondin-1 (TSP-1). Although, there is considerable evidence about the role of positive factors in angiogenesis, the role of negative factors is not well defined. In physiological conditions, such as resistance training as one of the effective training methods to improve cardiovascular function, the role of these factors is not properly known. The aim of this study was to investigate the changes in thrombospondin-1 and follistatin-like factor-1 of heart tissue following six weeks of resistance training in obese male rats. Materials and Methods: In an experimental study, 20 male Wistar rats were divided into two equal groups of control and experimental based on their body weight. Prior to the exercise protocol, the rats received a high-calorie diet. The experimental group participated in a six-week training protocol with a frequency of three training sessions per week, and each session included 10 repetitions with a 90-second rest interval, climbing a resistance training ladder with a height of one meter and an 85-degree incline with a weight attached to the base of the tail (based on the the maximum weight carrying capacity of each rat). Fourty-eight hours after the last training session, TSP-1 and FSTL-1 values in the heart tissue were evaluated using ELISA technique. Between-group comparisons were made by using the independent t-test at a significance level of P

Age-related macular degeneration (AMD) is a degenerative eye disease leading to central vision loss and is characterized by dysregulated autophagy of the retinal pigment epithelium (RPE) layer. Recent studies have suggested that rho-associated protein kinase (ROCK) inhibitors may enhance autophagy in neurodegenerative diseases and promote the survival of RPE cells. This study investigated the effect of ROCK inhibitors on autophagy gene expression and autophagic vacuole formation in a human RPE (ARPE-19) cell line. The highly selective and potent ROCK inhibitor Y-39983 enhanced the expression of autophagy genes in ARPE-19 cells and increased autophagic vacuole formation. A proteomic analysis using mass spectrometry was performed to further characterize the effects of ROCK inhibition at the protein level. Y-39983 downregulated thrombospondin-1 (THBS1), and suppression of THBS1 in ARPE-19 cells resulted in an increase in autophagic vacuole formation. Our data showed that ROCK inhibitor-induced autophagy was mediated by THBS1 downregulation. We identified ROCK and THBS1 as potential novel therapeutic targets in AMD.

Extended liver resection carries the risk of post-surgery liver failure involving thrombospondin-1-mediated aggravation of hepatic epithelial plasticity and function. Mesenchymal stromal cells (MSCs), by interfering with thrombospondin-1 (THBS1), counteract hepatic dysfunction, though the mechanisms involved remain unknown. Herein, two-thirds partial hepatectomy in mice increased hepatic THBS1, downstream transforming growth factor-β3, and perturbation of liver tissue homeostasis. All these events were ameliorated by hepatic transfusion of human bone marrow-derived MSCs. Treatment attenuated platelet and macrophage recruitment to the liver, both major sources of THBS1. By mitigating THBS1, MSCs muted surgery-induced tissue deterioration and dysfunction, and thus supported post-hepatectomy regeneration. After liver surgery, patients displayed increased tissue THBS1, which is associated with functional impairment and may indicate a higher risk of post-surgery complications. Since liver dysfunction involving THBS1 improves with MSC treatment in various animal models, it seems feasible to also modulate THBS1 in humans to impede post-surgery acute liver failure. [ABSTRACT FROM AUTHOR]

Glioblastoma (GB), the most malignant subtype of diffuse glioma, is highly aggressive, invasive and vascularized. Its median survival is still short even with maximum standard care. There is a need to identify potential new molecules and mechanisms, that are involved in the interactions of GB cells with the tumor microenvironment (TME), for therapeutic intervention. Thrombospondin-1 (TSP1) is a multi-faceted matricellular protein which plays a significant role in development, physiology and pathology including cancer. Recent studies have pinpoint an important role of TSP1 in GB development which will be summarized and discussed herein. We will discuss studies, mainly from preclinical research, which should lead to a deeper understanding of TSP1's role in GB development. We will also discuss some issues with regard to the use of this knowledge for the clinic. [ABSTRACT FROM AUTHOR]

Angiogenesis is vital to developmental, regenerative and repair processes. It is normally regulated by a balanced production of pro- and anti-angiogenic factors. Alterations in this balance under pathological conditions are generally mediated through up-regulation of pro-angiogenic and/or downregulation of anti-angiogenic factors, leading to growth of new and abnormal blood vessels. The pathological manifestation of many diseases including cancer, ocular and vascular diseases are dependent on the growth of these new and abnormal blood vessels. Thrompospondin-1 (TSP1) was the first endogenous angiogenesis inhibitor identified and its anti-angiogenic and anti-inflammatory activities have been the subject of many studies. Studies examining the role TSP1 plays in pathogenesis of various ocular diseases and vascular dysfunctions are limited. Here we will discuss the recent studies focused on delineating the role TSP1 plays in ocular vascular development and homeostasis, and pathophysiology of various ocular and vascular diseases with a significant clinical relevance to human health. [ABSTRACT FROM AUTHOR]

Thrombospondins (TSPs) have numerous different roles in cancer, regulating the behavior of cancer cells and non-neoplastic cells, and defining the responses of tumor cells to environmental changes, thorough their ability to orchestrate cellular and molecular interactions in the tumor microenvironment (TME). As a result of these activities, TSPs can also control drug delivery and activity, tumor response and resistance to therapies, with different outcomes depending on the nature of TSP-interacting cell types, receptors, and ligands, in a highly context-dependent manner. This review, focusing primarily on TSP-1, discusses the effects of TSPs on tumor response to chemotherapy, antiangiogenic, low-dose metronomic chemotherapy, immunotherapy, and radiotherapy, by analyzing TSP activity on different cell compartments – tumor cells, vascular endothelial cells and immune cells. We review evidence of the value of TSPs, specifically TSP-1 and TSP-2, as biomarkers of prognosis and tumor response to therapy. Finally, we examine possible approaches to develop TSP-based compounds as therapeutic tools to potentiate the efficacy of anticancer therapy. [ABSTRACT FROM AUTHOR]

Thrombospondin-1 is a secreted matricellular glycoprotein that modulates cell behavior by interacting with components of the extracellular matrix and with several cell surface receptors. Its presence in the extracellular matrix is induced by injuries that cause thrombospondin-1 release from platelets and conditions including hyperglycemia, ischemia, and aging that stimulate its expression by many cell types. Conversely, rapid receptor-mediated clearance of thrombospondin-1 from the extracellular space limits its sustained presence in the extracellular space and maintains sub-nanomolar physiological concentrations in blood plasma. Roles for thrombospondin-1 signaling, mediated by specific cellular receptors or by activation of latent TGFβ, have been defined in T and B lymphocytes, natural killer cells, macrophages, neutrophils, and dendritic cells. In addition to regulating physiological nitric oxide signaling and responses of cells to stress, studies in mice lacking thrombospondin-1 or its receptors have revealed important roles for thrombospondin-1 in regulating immune responses in infectious and autoimmune diseases and antitumor immunity. [Display omitted] [ABSTRACT FROM AUTHOR]

• The expression of thrombospondin-1 is significantly increased with the development of LFH. • Thrombospondin-1 promotes the development of LFH through the TGFβ1/Smad3 signaling pathway. • Sestrin2 significantly restrains the fibrotic process of LF cells through the THBS1/TGFβ1 pathway. • The inhibition of THBS1 expression could be a new therapeutic target for treating LFH. Lumbar spinal canal stenosis is primarily caused by ligamentum flavum hypertrophy (LFH), which is a significant pathological factor. Nevertheless, the precise molecular basis for the development of LFH remains uncertain. The current investigation observed a notable increase in thrombospondin-1 (THBS1) expression in LFH through proteomics analysis and single-cell RNA-sequencing analysis of clinical ligamentum flavum specimens. In laboratory experiments, it was demonstrated that THBS1 triggered the activation of Smad3 signaling induced by transforming growth factor β1 (TGFβ1), leading to the subsequent enhancement of COL1A2 and α-SMA, which are fibrosis markers. Furthermore, experiments conducted on a bipedal standing mouse model revealed that THBS1 played a crucial role in the development of LFH. Sestrin2 (SESN2) acted as a stress-responsive protein that suppressed the expression of THBS1, thus averting the progression of fibrosis in ligamentum flavum (LF) cells. To summarize, these results indicate that mechanical overloading causes an increase in THBS1 production, which triggers the TGFβ1/Smad3 signaling pathway and ultimately results in the development of LFH. Targeting the suppression of THBS1 expression may present a novel approach for the treatment of LFH. [ABSTRACT FROM AUTHOR]

In vivo and in vitro studies have demonstrated that thrombospondin-1 (TSP-1) is involved in atherosclerotic pathogenesis. However, the role of TSP-1 in clinical atherosclerosis remains unknown. This cross-sectional study investigated the relationship between TSP-1 and carotid intima–media thickness (IMT) and examined whether it interacts with conventional cardiovascular risk factors. A total of 587 participants were enrolled from February 2018 to December 2021. TSP-1 was dichotomized based on median value. Carotid IMT was measured bilaterally in each segment, and the average value was taken as the overall IMT variable. Analysis of covariance models were used to ascertain the main and interaction effects of cardiovascular risk factors and circulating TSP-1 levels on carotid IMT. Those with high TSP-1 (n = 294) had significantly higher carotid IMT than did those with low TSP-1 (n = 293; 0.74 ± 0.12 vs 0.72 ± 0.11 mm; p = 0.011). After the combined effects of TSP-1 and vascular risk factors on carotid IMT were evaluated, an interaction effect on IMT was observed between TSP-1 and hypertension (adjusted F = 8.760; p = 0.003). Stratification analysis revealed that individuals with hypertension and high TSP-1 had significantly higher IMT than did those with low TSP-1 (adjusted p = 0.007). However, this difference was not observed in normotensive individuals (adjusted p = 0.636). In conclusion, this is the first study to provide clinical data supporting the correlation between TSP-1 and atherosclerosis. TSP-1 may be a crucial marker of increased susceptibility to atherosclerosis in individuals with hypertension. [ABSTRACT FROM AUTHOR]

Age-related macular degeneration (AMD) is a vision threatening disease in older adults. Anti-VEGF treatment is effective for the majority of neovascular AMD (nAMD) patients, although approximately 30% of nAMD patients have an incomplete response for unknown reasons. Here we assessed the contribution of single nucleotide polymorphisms (SNPs) in key angioinflammatory regulatory genes in nAMD patients with an incomplete response compared to those responsive to anti-VEGF treatment. A total of 25 responsive and 30 nAMD patients with an incomplete response to anti-vascular endothelial growth factor (anti-VEGF) treatment were examined for known SNPs that impact the structure and function of thromobospondin-1 (TSP1), Bcl-2-interacting mediator of cell death (BIM) and complement factor H (CFH). Plasma levels of C-C motif chemokine ligand 2 (CCL2/MCP1), TSP1 and VEGF were assessed by ELISA. Patients responsive to anti-VEGF treatment showed a significant increase in the TSP1 rs2228262 AA allele and a trend for the BIM (rs724710) CT allele. Consistent with previous reports, 42% of the patients responsive to anti-VEGF expressed the CC allele for CFH rs1061170. Although the CFH TT allele had similarly low prevalence in both groups, the TC allele tended to be more prevalent in patients with an incomplete response. Patients with an incomplete response also had increased plasma CCL2/MCP1 levels, consistent with the role increased inflammation has in the pathogenesis of nAMD. Our studies point to new tools to assess the potential responsiveness of nAMD patients to anti-VEGF treatment and suggest the potential use of anti-CCL2 for treatment of nAMD patients with an incomplete response to anti-VEGF. [ABSTRACT FROM AUTHOR]

Background: Scleral extracellular matrix (ECM) remodeling plays a crucial role in the development of myopia, particularly in ocular axial elongation. Thrombospondin-1 (THBS1), also known as TSP-1, is a significant cellular protein involved in matrix remodeling in various tissues. However, the specific role of THBS1 in myopia development remains unclear. Method: We employed the HumanNet database to predict genes related to myopic sclera remodeling, followed by screening and visualization of the predicted genes using bioinformatics tools. To investigate the potential target gene Thbs1, we utilized lens-induced myopia models in male C57BL/6J mice and performed Western blot analysis to detect the expression level of scleral THBS1 during myopia development. Additionally, we evaluated the effects of scleral THBS1 knockdown on myopia development through AAV sub-Tenon's injection. The refractive status and axial length were measured using a refractometer and SD-OCT system. Results: During lens-induced myopia, THBS1 protein expression in the sclera was downregulated, particularly in the early stages of myopia induction. Moreover, the mice in the THBS1 knockdown group exhibited alterations in myopia development in both refraction and axial length changed compared to the control group. Western blotting analysis confirmed the effectiveness of AAV-mediated knockdown, demonstrating a decrease in COLA1 expression and an increase in MMP9 levels in the sclera. Conclusion: Our findings indicate that sclera THBS1 levels decreased during myopia development and subsequent THBS1 knockdown showed a decrease in scleral COLA1 expression. Taken together, these results suggest that THBS1 plays a role in maintaining the homeostasis of scleral extracellular matrix, and the reduction of THBS1 may promote the remodeling process and then affect ocular axial elongation during myopia progression. [ABSTRACT FROM AUTHOR]

Aims/Introduction: Thrombospondin‐1 (TSP‐1) participates in a series of physiological and pathological processes by binding to various receptors regulating cell proliferation, adhesion and apoptosis. Elevated circulating TSP‐1 is linked with diabetic vascular complications (DVC). This study aimed to determine the relationship between circulating TSP‐1 levels and DVC. Materials and Methods: A comprehensive search of PubMed, Embase, Web of Science and CNKI databases was carried out. A meta‐analysis was carried out to compare circulating TSP‐1 levels between diabetes patients without vascular complications (DNVC), diabetes patients with DVC and non‐diabetes patients. The correlation between TSP‐1 and metabolic parameters was also analyzed. Subgroup analysis was carried out according to complication type, defined as diabetic retinopathy, diabetic nephropathy and diabetic cardiovascular disease (DCVD). Results: A total of eight studies were included. Compared with non‐diabetes patients, diabetic patients, including DNVC and DVC, had significantly higher circulating TSP‐1 levels (standardized mean difference [SMD] 2.660, 95% CI 1.17–4.145, P = 0.000). DNVC had significantly higher circulating TSP‐1 levels than non‐diabetes patients (SMD 3.613, 95% CI 1.607–5.619, P = 0.000). DVC had significantly higher TSP‐1 levels than DNVC (SMD 0.568, 95% CI 0.100–1.036, P = 0.017). TSP‐1 was significantly positively correlated with fasting plasma glucose (overall Fisher's z = 0.696, 95% CI 0.559–0.833) and HbA1c (overall Fisher's z = 0.849, 95% CI 0.776–0.923). Conclusions: Elevated circulating TSP‐1 levels are closely related to DVC, especially in diabetic nephropathy and diabetic cardiovascular disease. Circulating TSP‐1 detection might be helpful in the timely diagnosis and treatment of DVC. [ABSTRACT FROM AUTHOR]

Alterations in angiogenic properties play a pivotal role in the manifestation and onset of various pathologies, including vascular diseases and cancer. Thrombospondin-1 (TSP1) protein is one of the master regulators of angiogenesis. This study unveils a novel aspect of TSP1 regulation through reversible phosphorylation. The silencing of the B55α regulatory subunit of protein phosphatase 2A (PP2A) in endothelial cells led to a significant decrease in TSP1 expression. Direct interaction between TSP1 and PP2A-B55α was confirmed via various methods. Truncated TSP1 constructs were employed to identify the phosphorylation site and the responsible kinase, ultimately pinpointing PKC as the enzyme phosphorylating TSP1 on Ser93. The biological effects of B55α–TSP1 interaction were also analyzed. B55α silencing not only counteracted the increase in TSP1 expression during wound closure but also prolonged wound closure time. Although B55α silenced cells initiated tube-like structures earlier than control cells, their spheroid formation was disrupted, leading to disintegration. Cells transfected with phosphomimic TSP1 S93D exhibited smaller spheroids and reduced effectiveness in tube formation, revealing insights into the effects of TSP1 phosphorylation on angiogenic properties. In this paper, we introduce a new regulatory mechanism of angiogenesis by reversible phosphorylation on TSP1 S93 by PKC and PP2A B55α. [ABSTRACT FROM AUTHOR]

Infectious complications of autologous hematopoietic stem cell transplantation (AHSCT) are the most common adverse effects of the therapy, resulting in prolonged hospitalization and deterioration of patient well‐being. Identifying predictors of these complications is essential for improving patient outcomes and guiding clinical management. This study aimed to examine thrombospondin‐1 (THBS‐1) serum levels as a potential biomarker for predicting bacteremia in AHSCT recipients. Blood samples were collected from 30 patients undergoing BeEAM/BEAM (bendamustine/carmustine, etoposide, cytarabine, melphalan) conditioning regimen at subsequent time points during AHSCT. THBS‐1 levels were quantified using ELISA kits. Patients who developed bacteremia (n = 11) during the AHSCT course had lower THBS‐1 concentration compared with those without (n = 19) (22.88 ± 11.53 µg/mL vs. 15.24 ± 5.62 µg/mL, p =.0325). The ROC curve analysis revealed that THBS‐1 serum concentration at the first day of BeEAM/BEAM regimen had an area under the curve of 0.732 (95%CI: 0.5390.925, p =.0186) with an optimal cut‐off value of 16.5 µg/ml resulting in 82% Sensitivity and 53% Specificity for predicting bacteremia with a median of 11 days before its occurrence. Patients with lower THBS‐1 concentrations experienced febrile neutropenia significantly earlier, with a median difference of 5 days (p =.0037). Patients with a low concentration of THBS‐1 had a higher risk of bacteremia and a shorter time to febrile neutropenia, indicating its potential value as a complications biomarker. Patients with lower serum THBS‐1 concentrations, indicating an increased risk, may be more suitable for an inpatient AHSCT procedure, where close monitoring and immediate intervention are accessible. [ABSTRACT FROM AUTHOR]

Fucosylation plays a critical role in cell‐to‐cell interactions and disease progression. However, the effects of fucosylation on splenocytes and their interactions with T cells remain unclear. In this study, we aimed to explore the transcriptome profiles of splenocytes deficient in fucosyltransferase (FUT) 1, an enzyme that mediates fucosylation, and investigate their impact on the proliferation and differentiation of T cells. We analysed and compared the transcriptomes of splenocytes isolated from Fut1 knockout (KO) mice and those from wild‐type (WT) mice using RNA‐seq. Additionally, we examined the effects of Fut1 KO splenocytes on CD4 T cell proliferation and differentiation, in comparison to WT splenocytes, and elucidated the mechanisms involved. The comparative analysis of transcriptomes between Fut1 KO and WT splenocytes revealed that thrombospondin‐1, among the genes related to immune response and inflammation, was the most highly downregulated gene in Fut1 KO splenocytes. The reduced expression of thrombospondin‐1 was further confirmed using qRT‐PCR and flow cytometry. In coculture experiments, Fut1 KO splenocytes promoted the proliferation of CD4 T cells and drove their differentiation toward Th1 and Th17 cells, compared with WT splenocytes. Moreover, the levels of IL‐2, IFN‐γ and IL‐17 were increased, while IL‐10 was decreased, in T cells cocultured with Fut1 KO splenocytes compared with those with WT splenocytes. These effects of Fut1 KO splenocytes on T cells were reversed when thrombospondin‐1 was replenished. Taken together, our results demonstrate that splenocytes with Fut1 deficiency promote CD4 T cell proliferation and Th1/Th17 differentiation at least in part through thrombospondin‐1 downregulation. [ABSTRACT FROM AUTHOR]

Introduction: Diabetic tendinopathy is a common invalidating and challenging disease that may be treated using stem cells. However, the effects of adipose-derived mesenchymal stem cell conditioned medium (ASC-CM) in diabetic tendinopathy have never been explored. Objectives: The present study evaluated the effects of ASC-CM on morphology, cell viability, structure, and scratch wound closure of human tenocytes (HTNC) exposed to high glucose (HG). Design: Experimental study. Methods: HTNC were exposed to HG (25 mM) for 7, 14 and 21 days with or without ASC-CM for the last 24 h. CM was collected from 4 × 105 ASCs, centrifuged for 10 min at 200 g and sterilized with 0.22 μm syringe filter. Results: At 7 days, HG-HTNC had decreased cell viability [72 ± 2%, p < 0.01 versus normal glucose (NG)] compared to NG-HTNC (90 ± 5%). A further decrement was detected after 14 and 21 days (60 ± 4% and 60 ± 5%, both, p < 0.01 versus NG and p < 0.01 versus HG7). While NG-HTNC evidenced a normal fibroblast cell-like elongated morphology, HG-HTNC showed increased cell roundness. In contrast, HG-HTNC exposed to ASC-CM showed a significant increase in cell viability, an improved cell morphology and higher scratch wound closure at all HG time points. Moreover, the exposure to ASC-CM significantly increased thrombospondin 1 and transforming growth factor beta 1 (TGF-β1) content in HG-HTNC. The TGF-β1 elevation was paralleled by higher Collagen I and Vascular Endothelial Growth Factor in HG-HTNC. Conclusion: ASC-CM may restore the natural morphology, cell viability and structure of HTNC, promoting their scratch wound closure through TGF-β1 increase. [ABSTRACT FROM AUTHOR]

Background and Purpose: Physiological angiogenesis and homeostasis of blood vessels is a complex process that is regulated at a high level by the balance between positive proteins such as follistatin-like factor-1 (FSTL-1) and negative proteins such as thrombospondin-1 (TSP-1). Although, there is considerable evidence about the role of positive factors in angiogenesis, the role of negative factors is not well defined. In physiological conditions, such as resistance training as one of the effective training methods to improve cardiovascular function, the role of these factors is not properly known. The aim of this study was to investigate the changes in thrombospondin-1 and follistatin-like factor-1 of heart tissue following six weeks of resistance training in obese male rats. Materials and Methods: In an experimental study, 20 male Wistar rats were divided into two equal groups of control and experimental based on their body weight. Prior to the exercise protocol, the rats received a high-calorie diet. The experimental group participated in a six-week training protocol with a frequency of three training sessions per week, and each session included 10 repetitions with a 90-second rest interval, climbing a resistance training ladder with a height of one meter and an 85-degree incline with a weight attached to the base of the tail (based on the the maximum weight carrying capacity of each rat). Fourtyeight hours after the last training session, TSP-1 and FSTL-1 values in the heart tissue were evaluated using ELISA technique. Between-group comparisons were made by using the independent t-test at a significance level of P<0.05. Results: Data analyses revealed that six weeks of resistance training in the experimental group compared to the control group caused a significant increase in FSTL-1 values (P=0.0001) and a non-significant decrease in TSP-1 values (P=0.09). Conclusion: Based on the findings of the present study it could be concluded that exercise in the form of resistance exercises can have positive effects on the development of angiogenesis process in heart tissue and it seems that six weeks of resistance training, despite the non-significant decrease in TSP-1 as an inhibitory factor in the angiogenesis process and an increase in FSTL-1 values as an angiogenesis stimulating factor, may have positive effect on improving blood supply to the heart muscle in obese subjects. The data of the present study refer to the role of resistance training in facilitating intracellular signaling through, modulating some inhibitory factors and stimulatory factors of angiogenesis in heart tissue of obese rats. [ABSTRACT FROM AUTHOR]

Abstract Preeclampsia (PE) is considered as a disease of placental origin. However, the specific mechanism of placental abnormalities remains elusive. This study identified thrombospondin‐1 (THBS1) is downregulated in preeclamptic placentae and negatively correlated with blood pressure. Functional studies show that THBS1 knockdown inhibits proliferation, migration, and invasion and increases the cycle arrest and apoptosis rate of HTR8/SVneo cells. Importantly, THBS1 silencing induces necroptosis in HTR8/SVneo cells, accompanied by the release of damage‐associated molecular patterns (DAMPs). Necroptosis inhibitors necrostatin‐1 and GSK′872 restore the trophoblast survival while pan‐caspase inhibitor Z‐VAD‐FMK has no effect. Mechanistically, the results show that THBS1 interacts with transforming growth factor B‐activated kinase 1 (TAK1), which is a central modulator of necroptosis quiescence and affects its stability. Moreover, THBS1 silencing up‐regulates the expression of neuronal precursor cell‐expressed developmentally down‐regulated 4 (NEDD4), which acts as an E3 ligase of TAK1 and catalyzes K48‐linked ubiquitination of TAK1 in HTR8/SVneo cells. Besides, THBS1 attenuates PE phenotypes and improves the placental necroptosis in vivo. Taken together, the down‐regulation of THBS1 destabilizes TAK1 by activating NEDD4‐mediated, K48‐linked TAK1 ubiquitination and promotes necroptosis and DAMPs release in trophoblast cells, thus participating in the pathogenesis of PE.

Background and Purpose: The expansion of fat tissue depends on its angiogenesis rate, and exercise affect on various angiogenic factors in this tissue. With the expansion of fat tissue and adipogenesis, a dense and closed capillary network is formed in this tissue, which can suppress angiogenic factors. If there is a wide capillary network and angiogenic factors such as VEGF-A in this tissue, the expansion of fat tissue can be prevented. The aim of this study was to investigate and compare the effect of a variety of endurance training on the expression of angiogenic genes of vascular endothelial growth factor (VEGF-A) and thrombospondin-1 (TSP-1) in the subcutaneous fat tissue of rats. Materials and Methods: In this experimental study, 32 male Wistar rats aged eight weeks and weighing 237±33 grams were randomly divided into four equal groups of control, high-intensity progressive continuous aerobic training (HIT), moderate-intensity continuous aerobic training (MIT) and, high-intensity interval aerobic training (HIIT). The treadmill training protocols were conducted for eight weeks, five sessions per week, where the HIT training consisted of running at a speed of 20 m/min or at an intensity of 65% of the maximum oxygen consumption (VO2max), with a gradually increasing slope for 30 minutes. MIT training consisted of running at an intensity of 65% VO2max for 37 minutes, and HIIT training consisted of four high-intensity intervals with four minutes of running at an intensity of 90-100% VO2max and four low-intensity intervals with a duration of three minutes at 50-60% VO2max (28 minutes in total). Finally, 48 hours after the last training session, the subcutaneous fat tissue was isolated and the expression of VEGF-A and TSP-1 genes in the subcutaneous fat tissue was measured by RT-qPCR technique. The data were analyzed using a one-way analysis of variance and Tukey's post hoc test, and the significance level was considered P≤0.05. Results: Statistical analyses showed that all three exercise interventions significantly increased the expression of the VEGF-A gene in subcutaneous fat tissue. However, only HIT training could significantly reduce the expression of TSP-1 in this tissue (P˂0.05). In addition, the increase in VEGF-A expression was significantly higher after HIT training compared to HIIT (P˂0.05). Conclusion: According to the findings of this study, high-intensity progressive continuous aerobic training is probably the most desirable training to increase angiogenesis in subcutaneous fat tissue. These types of exercises can be effective in reducing fat mass by improving blood supply to fat tissue. Keywords: Exercise Training, Angiogenesis, Adipose Tissue, Thrombospondin-1

Abstract Thrombospondin-1 (TSP1) contributes to obesity-associated inflammation via activating Toll-like receptor 4 (TLR4). The regulatory role of vitamin D on this pathway has been suggested. This study aimed to investigate the relationship between TSP1/TLR4 pathway and vitamin D in obese and normal weight subjects with different metabolic phenotypes. Thirty obese and thirty normal weight men were selected. Anthropometric parameters and serum TSP1, TLR4, TNF-α, vitamin D, and metabolic profile were determined. Metabolic phenotypes of obese and normal weight subjects were determined. Findings revealed enhanced TSP1/TLR4/TNF-α levels and reduced 25(OH)D levels in obese compared to normal weight subjects and metabolically unhealthy compared to metabolically healthy subjects. TSP1 correlated positively with parameters of unhealthy metabolic profile. TSP1, TLR4 and TNF-α levels significantly negatively correlated with vitamin D levels. In conclusion, vitamin D might exert a regulatory role on TSP1/TLR4 pathway, providing a potential mechanism that links hypovitaminosis D with risk of metabolic dysfunction.

Objective To investigate the effects of thrombospondin1 (THBS1) gene knockout on immune microenvironment and tumor progression of colorectal cancer. Methods THBS1 gene knockout (THBS1-/-) mice were constructed and its genotypes were determined by PCR and agarose gel electrophoresis. Subcutaneous tumor bearing and intraperitoneal implantation metastasis models of colorectal cancer were constructed in wild type (WT) and THBS1-/- mice to observe the effect of THBS1 on tumor growth. Immune cells in epididymal adipose of tumor bearing mice of both types were detected by flow cytometry. Results Compared with the WT mice, THBS1-/- mice showed no difference in tumor growth in colorectal cancer subcutaneous tumor bearing model (P>0.05), but significantly inhibited tumor growth in intraperitoneal implantation metastasis model (P < 0.05). Subsequently, flow cytometry indicated that the proportion of total macrophages in the epididymal adipose tissue was increased in the THBS1-/- mice than the WT mice (P < 0.01), with the proportion of M1-like macrophages (typical or proinflammatory type) increased (P < 0.01) and that of M2-like macrophages (alternately activated or anti-inflammatory type) decreased (P < 0.01). The proportion of myeloid-derived suppressor cells (MDSC) was decreased (P < 0.05), that of Ly6C subgroup was increased (P < 0.01), that of Ly6G subgroup was decreased (P < 0.05), that of CD8+ T cells was significantly increased (P < 0.01), and that of CD4+ T cells was decreased (P < 0.01). There were no changes in the proportions of total macrophages, M1-like macrophages and M2-like macrophages in the peripheral blood of intraperitoneal implantation metastasis model mice (P>0.05). The proportions of MDSC and ly6C subgroup were not changed (P>0.05), while that of ly6G subgroup were decreased (P < 0.05). The proportion of CD8+ T cells was significantly decreased (P < 0.05), while that of CD4+ T cells was not changed (P>0.05). Conclusion THBS1 gene knockout inhibits the intraperitoneal metastasis of colorectal cancer cells by enhancing tumor immunity.

The use of checkpoint-blockade antibodies is still restricted in several malignancies due to the modest efficacy, despite considerable success in anti-tumor immunotherapy. The poor response of cancer cells to immune destruction is an essential contributor to the failure of checkpoint therapy. We hypothesized that combining checkpoint therapy with natural-product chemosensitizer could enhance immune response. Herein, a targeted diterpenoid derivative was integrated with the checkpoint blockade (anti-CTLA-4) to improve immunotherapy using thermosensitive liposomes as carriers. In vivo, the liposomes enabled the co-delivery of the two drug payloads into the tumor. Consequently, the regulatory T cell proliferation was restrained, the cytotoxic T cell infiltration was enhanced, and the profound immunotherapeutic effect was achieved. In addition, the immunotherapeutic effect of another clinically used checkpoint antibody, anti-PD-1, also benefited from the diterpenoid derivative. Of note, our mechanism study revealed that the targeted diterpenoid derivative increased the sensitivity of cancer cells to immune attack via THBS1 downregulation and the resultant destruction of THBS1-CD47 interaction. Collectively, co-delivering THBS1 inhibitor and checkpoint blockade is promising to boost cancer immunotherapy. We first time discovered that THBS1 suppression could strengthen checkpoint therapy.

Introduction: Alterations in the endothelium and endothelial adhesion proteins such as von Willebrand factor (vWF) play major roles in hypercoagulability in thalassemia. vWF protein release leads to platelet aggregation and thrombi formation at the site of vascular injury. It is then degraded by the proteolytic enzyme ADAMTS13. Thrombospondin‐1 is a multifactorial glycoprotein, which was reported to compete with ADAMTS13 for sites of vWF proteolysis. In this study, levels of vWF, ADAMTS13, and TSP‐1 proteins were determined in β‐thalassemia major patients. A possible association between TSP‐1 and vWF and ADAMTS‐13 was also evaluated. Methods: The study was conducted on 80 β‐thalassemia major patients and 80 age and sex matched healthy controls. The 80 patients were sub‐divided into two groups; splenectomised and non‐splenectomised. vWF, ADAMTS13 and TSP‐1 plasma level were measured using ELISA technique. Results: There was no significant difference in vWF and TSP‐1 levels between patients and controls (p > 0.05). However, ADAMTS13 levels and ADAMTS13 activity/vWF antigen ratio were significantly higher in patients compared to controls (p < 0.05). VWF antigen and TSP‐1 level were significantly higher in splenectomised patients (p = 0.025 and p < 0.001, respectively). We also observed a significant decrease in ADAMTS13 activity/vWF antigen ratio among splenectomised compared to non‐ splenectomised patients (p = 0.019). Correlation analysis showed a significant negative correlation between TSP‐1 and vWF Collagen Binding Activity (r = −0.394, p = 0.021) and a positive correlation with ADAMTS13 activity/vWF antigen ratio (r = 0.356, p = 0.039) in splenectomised compared to non‐ splenectomised patients. Conclusion: Our findings highlight the adequacy of patient management protocols for β‐TM in Kuwait as patients presented with comparable levels of platelets, vWF and TSP‐1 compared to normal controls. The reported increase in ADAMTS13 in patients may be required to maintain normal levels of vWF. Although no active thrombotic episodes were reported at the time of the study, the significant rise in platelets, vWF:Ag and TSP‐1 levels in splenectomised patients may indicate a tendency towards hypercoagulability. Monitoring of splenectomised patients is recommended. [ABSTRACT FROM AUTHOR]

Unfolded protein response (UPR) signaling and endoplasmic reticulum (ER) stress have been linked to pulmonary fibrosis. However, the relationship between UPR status and pulmonary function and prognosis in idiopathic pulmonary fibrosis (IPF) patients remains largely unknown. Through a series of bioinformatics analyses, we established a correlation between UPR status and pulmonary function in IPF patients. Furthermore, thrombospondin-1 (TSP-1) was identified as a potential biomarker for prognostic evaluation in IPF patients. By utilizing both bulk RNA profiling and single-cell RNA sequencing data, we demonstrated the upregulation of TSP-1 in lung fibroblasts during pulmonary fibrosis. Gene set enrichment analysis (GSEA) results indicated a positive association between TSP-1 expression and gene sets related to the reactive oxygen species (ROS) pathway in lung fibroblasts. TSP-1 overexpression alone induced mild ER stress and pulmonary fibrosis, and it even exacerbated bleomycin-induced ER stress and pulmonary fibrosis. Mechanistically, TSP-1 promoted ER stress and fibroblast activation through CD47-dependent ROS production. Treatment with either TSP-1 inhibitor or CD47 inhibitor significantly attenuated BLM-induced ER stress and pulmonary fibrosis. Collectively, these findings suggest that the elevation of TSP-1 during pulmonary fibrosis is not merely a biomarker but likely plays a pathogenic role in the fibrotic changes in the lung. [ABSTRACT FROM AUTHOR]

Thrombospondin-1 (TSP1) contributes to obesity-associated inflammation via activating Toll-like receptor 4 (TLR4). The regulatory role of vitamin D on this pathway has been suggested. This study aimed to investigate the relationship between TSP1/TLR4 pathway and vitamin D in obese and normal weight subjects with different metabolic phenotypes. Thirty obese and thirty normal weight men were selected. Anthropometric parameters and serum TSP1, TLR4, TNF-α, vitamin D, and metabolic profile were determined. Metabolic phenotypes of obese and normal weight subjects were determined. Findings revealed enhanced TSP1/TLR4/TNF-α levels and reduced 25(OH)D levels in obese compared to normal weight subjects and metabolically unhealthy compared to metabolically healthy subjects. TSP1 correlated positively with parameters of unhealthy metabolic profile. TSP1, TLR4 and TNF-α levels significantly negatively correlated with vitamin D levels. In conclusion, vitamin D might exert a regulatory role on TSP1/TLR4 pathway, providing a potential mechanism that links hypovitaminosis D with risk of metabolic dysfunction. [ABSTRACT FROM AUTHOR]

Background and Objectives Coronary artery bypass graft (CABG) is a common therapeutic intervention for patients suffering from coronary heart diseases. The aim of this study was to determine the effect of selected combined rehabilitation exercises on the expression of thrombospondin-1 (TSP-1) and interleukin-1 beta (IL-1β) genes in patients following CABG surgery. Subjects and Methods In this semi-experimental study, 20 male patients from Afshar Hospital (Yazd city) after coronary artery surgery were purposefully selected and randomly divided into combined exercise and control groups. he combined exercise group engaged in a 10-week program (30 sessions, three per week) comprising aerobic exercises (15-20 minutes with an intensity of 50-60% of the maximum heart rate) and resistance exercises (10-20 minutes, encompassing three upper limb movements and two lower limb movements; each movement included three sets with 10 repetitions at 30-60% of the maximum repetition). Gene expression was measured using the RealTime PCR method. The data were analyzed using the Paired t-test and One-Way ANOVA at a significance level of P<0.05. Results Following the intervention period, a significant decrease in the expression of IL-1β was observed. However, no significant difference was noted in the expression of TSP-1. Conclusion The findings suggest that combined exercises, as a non-pharmacological rehabilitation intervention, can be beneficial for individuals post-CABG by reducing systemic inflammation. [ABSTRACT FROM AUTHOR]

Dupuytren's disease (DD) is a fibroproliferative disorder affecting the palmar fascia, causing functional restrictions of the hand and thereby limiting patients' daily lives. The disturbed and excessive myofibroblastogenesis, causing DD, is mainly induced by transforming growth factor (TGF)-β1. But, the extent to which impaired TGF-β1 release or TGF-β signal degradation is involved in pathologically altered myofibroblastogenesis in DD has been barely examined. Therefore, the complex in which TGF-β1 is secreted in the extracellular matrix to elicit its biological activity, and proteins such as plasmin, integrins, and matrix metalloproteinases (MMPs), which are involved in the TGF-β1 activation, were herein analyzed in DD-fibroblasts (DD-FBs). Additionally, TGF-β signal degradation via caveolin-1 was examined with 5-fluoruracil (5-FU) in detail. Gene expression analysis was performed via Western blot, PCR, and immunofluorescence analyses. As a surrogate parameter for disturbed myofibroblastogenesis, -smooth-muscle-actin (-SMA) expression was evaluated. It was demonstrated that latency-associated peptide (LAP)-TGF-β and latent TGF-β-binding protein (LTBP)-1 involved in TGF-β-complex building were significantly upregulated in DD. Plasmin a serinprotease responsible for the TGF-β release was significantly downregulated. The application of exogenous plasmin was able to inhibit disturbed myofibroblastogenesis, as measured via -SMA expression. Furthermore, a reduced TGF-β1 degradation was also involved in the pathological phenotype of DD, because caveolin-1 expression was significantly downregulated, and if rescued, myofibroblastogenesis was also inhibited. Therefore, our study demonstrates that a deficient release and degradation of TGF-β1 are important players in the pathological phenotype of DD and should be addressed in future research studies to improve DD therapy or other related fibrotic conditions. [ABSTRACT FROM AUTHOR]

Background and Purpose: The expansion of fat tissue depends on its angiogenesis rate, and exercise activities affect various angiogenic factors in this tissue. With the expansion of fat tissue and adipogenesis, a dense and closed capillary network is formed in this tissue, which can suppress angiogenic factors. If there is a wide capillary network and angiogenic factors such as VEGF-A in this tissue, the expansion of fat tissue can be prevented. The aim of this study was to investigate and compare the effect of a variety of endurance exercises on the expression of angiogenic genes vascular endothelial growth factor (VEGF-A) and thrombospondin-1 (TSP-1) in the subcutaneous fat tissue of rats. Materials and Methods: In this experimental study, 32 male Wistar rats aged eight weeks and weighing 237 ± 33 grams were randomly divided into four equal groups of control, high-intensity progressive continuous aerobic training (HIT), moderate-intensity continuous aerobic training (MIT) and, high-intensity interval aerobic training (HIIT). The treadmill training protocols consisted of eight weeks, so that the HIT training consisted of running at a speed of 20 m/min or at an intensity of 65% of the maximum oxygen consumption (VO2max), with a gradually increasing slope for 30 minutes. MIT training consisted of running with an intensity of 65% VO2max for 37 minutes, and HIIT training consisted of four high-intensity intervals with four minutes of running with an intensity of 90-100% VO2max and four low-intensity intervals with a duration of three minutes with 50-60% VO2max (28 minutes in total). Finally, 48 hours after the last training session, the subcutaneous fat tissue was isolated and the expression of VEGF-A and TSP-1 genes in the subcutaneous fat tissue was measured by RT-qPCR method. The resulting data were analyzed using a one-way analysis of variance and Tukey's post hoc test, and the significance level was considered P ≤ 0.05. Results: The findings of the present study showed that all three exercise interventions significantly increased the expression of the VEGF-A gene in subcutaneous fat tissue; But only HIT training could significantly reduce the expression of TSP-1 in this tissue (P < 0.05). Also, the increase in VEGF-A expression was significantly higher after HIT training compared to HIIT (P < 0.05). Conclusion: According to the findings of this study, high-intensity and progressive continuous aerobic training is probably the most desirable training method to increase angiogenesis in subcutaneous fat tissue. These types of exercises can be effective in reducing fat mass by improving blood supply to fat tissue. [ABSTRACT FROM AUTHOR]

BACKGROUND: Eosinophilic esophagitis (EoE) is a chronic TH2 disorder complicated by tissue fibrosis and loss of esophageal luminal patency. The fibrostenotic esophagus does not respond well to therapy, but profibrotic therapeutic targets are largely unclear. OBJECTIVE: Our aim was to utilize proteomics and primary cells as a novel approach to determine relevant profibrotic factors. METHODS: We utilized primary esophageal EoE and normal fibroblasts, their derivative extracellular matrixes (ECMs), an approach of fibroblast culture on autologous versus nonautologous ECM, and proteomics to elucidate EoE ECM proteins that dysregulate cellular function. RESULTS: We cultured esophageal fibroblasts from normal esophagi and esophagi from patients with severe EoE on autologous versus nonautologous ECM. The EoE ECM proteome shifted normal esophageal fibroblast protein expression. Proteomic analysis demonstrated that thrombospondin-1 is detected only in the EoE ECM, is central in the EoE ECM protein-protein interactome, is found at significantly elevated levels in biopsy specimens from patients with active EoE, and induces fibroblast collagen I production. CONCLUSION: Fibroblasts from patients with EoE secrete a unique ECM proteome that reflects their in vivo state and induces collagen I and α-smooth muscle actin protein expression from normal fibroblasts. Thrombospondin-1 is a previously unappreciated profibrotic molecule in EoE.

The balance of angiogenic factors, including vascular endothelial growth factor (VEGF), and angiostatic factors, like thrombospondin-1 (TSP-1) and endostatin, controls striated muscle angiogenic responses to exercise training. The effect of age on circulating levels of these factors following a bout of exercise is unclear. The authors hypothesized that older adults would have lower circulating VEGF but higher TSP-1 and endostatin after exercise compared with young adults. Ten young and nine older participants cycled for 45 min at 60% estimated HRmax. Serum [VEGF], [TSP-1], and [endostatin] obtained before (PREX), immediately after (POSTX0), and 3 hr after (POSTX3) exercise were analyzed. [VEGF] increased in older adults only from PREX to POSTX0 (p <.05). [TSP-1] increased in both age groups (p <.05). There was no effect of age or exercise on [endostatin]. In conclusion, immediately after exercise, both groups had a similar increase in [TSP-1], but [VEGF] increased in older adults only. [ABSTRACT FROM AUTHOR]

Roles of thrombospondin-1 (TSP-1) and thrombospondin-2 (TSP-2) in tissue repair and inflammation are well-documented, but the association of their serum expressions with the pathogenesis of COVID-19 remains unclear. We investigate the roles of TSP-1 and TSP-2 in COVID-19.

Objective To investigate the effect of thrombospondin-1(TSP-1) knockout on radiation-induced pulmonary fibrosis and explore its underlying mechanism. Methods Male wild type C57BL/6 mice (6~8 weeks old, WT mice) and TSP-1 knockout mice (TSP-1-/- mice) were subjected and received 16 Gy 60Co γ-ray whole lung irradiation (IR) to induce radiation pulmonary fibrosis, and then, the mice were assigned into WT+IR group and TSP-1-/-+IR group, respectively, with 6 mice in each group.In 16 weeks after irradiation, HE staining was performed to observe the morphological changes in lung tissues, and Sirius red staining was used to observe the collagen expression in lung tissues.qRT-PCR was employed to detect the mRNA expression of TGF-β1 and Collagen Ⅰ in lung tissues.Micro-CT scanning was adopted to evaluate lung injury and substantial lung changes.FlexiVent system was employed to assess pulmonary function.Immunofluorescence staining was conducted to measure the protein levels of LC-3 and p62 in lung tissues.Transmission electron microscopy (TEM) was used to observe the cellular autophagic vesicles in lung tissues. Results Compared with the WT+IR group, the TSP-1-/-+IR group had reduced lung injury and collagen deposition in lung tissue, significantly lower mRNA levels of TGF-β1 and Collagen Ⅰ in lung tissue (P < 0.01), and improved pulmonary function.Immunofluorescence assay and TEM showed that autophagy was observed in the mice of TSP-1-/-+IR group. Conclusion TSP-1 knockout can alleviate radiation-induced pulmonary fibrosis, which may be related to activation of autophagy.

The use of treatments, such as programmed death protein 1 (PD1) or cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) antibodies, that loosen the natural checks upon immune cell activity to enhance cancer killing have shifted clinical practice and outcomes for the better. Accordingly, the number of antibodies and engineered proteins that interact with the ligand–receptor components of immune checkpoints continue to increase along with their use. It is tempting to view these molecular pathways simply from an immune inhibitory perspective. But this should be resisted. Checkpoint molecules can have other cardinal functions relevant to the development and use of blocking moieties. Cell receptor CD47 is an example of this. CD47 is found on the surface of all human cells. Within the checkpoint paradigm, non-immune cell CD47 signals through immune cell surface signal regulatory protein alpha (SIRPα) to limit the activity of the latter, the so-called trans signal. Even so, CD47 interacts with other cell surface and soluble molecules to regulate biogas and redox signaling, mitochondria and metabolism, self-renewal factors and multipotency, and blood flow. Further, the pedigree of checkpoint CD47 is more intricate than supposed. High-affinity interaction with soluble thrombospondin-1 (TSP1) and low-affinity interaction with same-cell SIRPα, the so-called cis signal, and non-SIRPα ectodomains on the cell membrane suggests that multiple immune checkpoints converge at and through CD47. Appreciation of this may provide latitude for pathway-specific targeting and intelligent therapeutic effect. [ABSTRACT FROM AUTHOR]

Matricellular proteins comprise several families of secreted proteins that function in higher animals at the interface between cells and their surrounding extracellular matrix. Targeted gene disruptions that result in loss of viability in mice have revealed critical roles for several matricellular proteins in murine embryonic development, including two members of the cellular communication network (CCN) gene family. In contrast, mice lacking single or multiple members of the thrombospondin (THBS) gene family remain viable and fertile. The frequency of loss of function mutants, identified using human deep exome sequencing data, provided evidence that some of the essential genes in mice, including Ccn1, are also essential genes in humans. However, a deficit in loss of function mutants in humans indicated that THBS1 is also highly loss-intolerant. In addition to roles in embryonic development or adult reproduction, genes may be loss-intolerant in humans because their function is needed to survive environmental stresses that are encountered between birth and reproduction. Laboratory mice live in a protected environment that lacks the exposures to pathogens and injury that humans routinely face. However, subjecting Thbs1−/− mice to defined stresses has provided valuable insights into functions of thrombospondin-1 that could account for the loss-intolerance of THBS1 in humans. [ABSTRACT FROM AUTHOR]