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Objective: This study aims to investigate the expression levels of Nerve Growth Factor (NGF), the precursor form of NGF (proNGF), and p75 neurotrophin receptor (p75 NTR ) in lung injury induced by cerebral Ischemia-Reperfusion (I/R) in both young and elderly rats., Methods: Male Sprague-Dawley rats, categorized as young (3-months-old) and elderly (16-months-old), were divided into four experimental groups: Young Sham, Young I/R, Elderly Sham, and Elderly I/R. Each group underwent either sham surgery or ischemia-reperfusion treatment. Following 24 h post-procedure, the severity of cerebral ischemia was assessed using the Zea Longa 5-point scoring system, and lung tissue pathological changes were examined using Hematoxylin and Eosin (HE) staining. Western blot analysis was utilized to measure the expression levels of NGF, proNGF, and p75 NTR proteins in lung tissue., Results: Both young and elderly I/R groups exhibited lung tissue congestion and edema compared to their respective sham groups, with a significant increase in pathological scores (p < 0.05). Furthermore, the elderly I/R group demonstrated a significantly higher pathological score compared to the young I/R group (p < 0.05). Western blot analysis revealed that compared to the young sham group, the expression of NGF in the lung tissue of elderly sham rats decreased (p < 0.05), while proNGF and p75 NTR increased (p < 0.05). Additionally, compared to the sham group, the levels of NGF, proNGF, and p75 NTR in lung tissue were elevated in both young and elderly I/R groups of rats (p < 0.05). Moreover, the expression of proNGF and p75 NTR in lung tissue was higher in the elderly I/R group than in the young I/R group (p < 0.05)., Conclusion: Cerebral ischemia-reperfusion-induced lung injury was associated with increased expression of proNGF and p75 NTR , as well as decreased NGF expression in lung tissue. These alterations in NGF, proNGF, and p75 NTR may contribute to the susceptibility to age-related lung injury., Competing Interests: Declaration of competing interest All of the authors had no any personal, financial, commercial, or academic conflicts of interest separately., (Copyright © 2024 HCFMUSP. Published by Elsevier España, S.L.U. All rights reserved.)

Post-stroke depression (PSD) affects millions of patients who suffer cerebral stroke. However, the molecular mechanisms and pathophysiology are poorly understood. Previous studies have shown that exosomes have been proven to be involved in neuropsychiatric disorders such as stroke and post-stroke depression in neurotransmitter release, neuronal remodeling, and neuron angiogenesis. Here we extracted and purified hippocampal exosomes from stroke mouse model to investigate mechanisms of hippocampal exocytosis in PSD assessed by using behavioral tests and biochemical methods. Aiming at the effect of hippocampal exosomes from stroke on the development of PSD, behavioral test was compared including sugar water preference experiment, open fields, forced swimming test, to explore it in depth. Further, the expression of depression-related protein (proBDNF and p75NTR) and synapse-associated proteins (Synaptotagmin and PSD95) was evaluated by Western blotting, RT-qPCR or immunofluorescence staining. Density of dendritic protrusions of neurons was assessed by Golgi staining to measure changes in spine density after the treatment of hippocampal exosomes from stroke. Our results revealed that injection of exosomes from stroke models significantly aggravated depressive-like behaviors, increase of depression-related protein (proBDNF and p75NTR) expression and deficiency of synapse-associated proteins (Synaptotagmin and PSD95) expression, and the decreased number of spin density. Our findings together suggest that hippocampal exosomes from stroke cause exacerbation of depressive-like behavior in mice, possibly resulting from the regulation of neurogenesis by its depression-associated proteins (proBDNF and p75NTR). Therefore, hippocampal exosomes from stroke are promising targets for the diagnosis and treatment of PSD., Competing Interests: Declarations Competing interests The authors declare no competing interests. Consent for publication Not applicable. Ethics approval The protocol of this study was approved by the Ethics Committee of Zhongnan Hospital of Wuhan University. The study methodology was carried out following ARRIVE guidelines (https://arriveguidelines.org)., (© 2024. The Author(s).)

Peripheral taste neurons exhibit functional, genetic, and morphological diversity, yet understanding how or if these attributes combine into taste neuron types remains unclear. In this study, we used male and female mice to relate taste bud innervation patterns to the function of a subset of proenkephalin-expressing (Penk+) taste neurons. We found that taste arbors (the portion of the axon within the taste bud) stemming from Penk+ neurons displayed diverse branching patterns and lacked stereotypical endings. The range in complexity observed for individual taste arbors from Penk+ neurons mirrored the entire population, suggesting that taste arbor morphologies are not primarily regulated by the neuron type. Notably, the distinguishing feature of arbors from Penk+ neurons was their propensity to come within 110 nm (in apposition with) different types of taste-transducing cells within the taste bud. This finding is contrary to the expectation of genetically defined taste neuron types that functionally represent a single stimulus. Consistently, further investigation of Penk+ neuron function revealed that they are more likely to respond to innately aversive stimuli-sour, bitter, and high salt concentrations-as compared with the full taste population. Penk+ neurons are less likely to respond to nonaversive stimuli-sucrose, umami, and low salt-compared with the full population. Our data support the presence of a genetically defined neuron type in the geniculate ganglion that is responsive to innately aversive stimuli. This implies that genetic expression might categorize peripheral taste neurons into hedonic groups, rather than simply identifying neurons that respond to a single stimulus., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 the authors.)

This systematic review and meta-analysis appraised previous findings to uncover potential faecal intestinal permeability and intestinal inflammatory markers in older adults. A comprehensive literature search led to the identification of ten eligible studies with findings of potential faecal intestinal permeability (zonulin and alpha-1-antitrypsin) and intestinal inflammatory markers [calprotectin, lactoferrin and neutrophil gelatinase-associated lipocalin (NGAL)]. Most of the cases (n > 2) [Parkinson's disease (PD) and Alzheimer's disease (AD)] exhibited higher faecal alpha-1-antitrypsin, zonulin and calprotectin levels. The present meta-analysis confirmed significantly higher faecal alpha-1-antitrypsin in older persons with PD compared to non-PD [MD = 22.92 mg/dL; 95 % CI = 14.02-31.81, p < 0.00001; I 2 = 0 % (p = 0.73)]. There was, however, no significant difference in faecal zonulin between PD and non-PD individuals [MD = 26.88 ng/mL; 95 % CI = -29.26-83.01, p = 0.35; I 2 = 94 % (p < 0.0001)]. Meanwhile, faecal calprotectin was higher in older adults with GI symptoms, multiple system atrophy (MSA) or PD than the healthy controls [MD = 9.51 μg/g; 95 % CI = 0.07-18.95, p = 0.05; I 2 = 84 % (p < 0.00001)]. Altogether, faecal calprotectin appears to be a potential intestinal inflammatory marker whereas previous findings on faecal alpha-1-antitrypsin as an intestinal permeability marker remain limited and require further validation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Increasing evidence demonstrates that brain-derived neurotrophic factor (BDNF) can be regarded as a biomarker for major depression. Our previous work found that the ratio of mature BDNF (mBDNF) to precursor-BDNF (proBDNF) was a pivotal factor in the pathogenesis of major depressive disorder (MDD). But the mechanism behind the ratio is still obscure. Tissue plasminogen activator (tPA) and plasminogen activator inhibitor-1 (PAI-1) both play essential roles in depression by regulating the ratio of BDNF/proBDNF. In present study, we analyzed BDNF, proBDNF, tPA and PAI-1 in the peripheral blood in 57 MDD patients pre- and post-treatment and in 57 healthy controls. We verified that BDNF and tPA levels were significantly decreased, whereas proBDNF and PAI-1 levels elevated obviously in MDD group pre-treatment. And after 4 weeks SSRIs treatment, the BDNF and tPA levels increased while the proBDNF and PAI-1 levels reduced. The MDD pre-treatment group had the lowest ratio of BDNF to proBDNF compared to MDD post-treatment group and control group. Though the ratio of tPA/PAI-1 in MDD pre-treatment had not reached the significance, it was still the lowest one among the three groups. The combination of tPA + PAI + BDNF showed the best diagnostic value for MDD. In summary, our data suggested that the interaction between tPA and PAI-1 implicated to the MDD and the antidepressant treatment which might through regulating the BDNF/proBDNF ratio. The combination of tPA, PAI-1 and BDNF might offer a helpful way for MDD diagnosis., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Autism Spectrum Disorders (ASD) comprise a range of early age-onset neurodevelopment disorders with genetic heterogeneity. Most ASD related genes are involved in synaptic function, which is regulated by mature brain-derived neurotrophic factor (mBDNF) and its precursor proBDNF in a diametrically opposite manner: proBDNF inhibits while mBDNF potentiates synapses. Here we generated a knock-in mouse line (BDNF met/leu ) in which the conversion of proBDNF to mBDNF is attenuated. Biochemical experiments revealed residual mBDNF but excessive proBDNF in the brain. Similar to other ASD mouse models, the BDNF met/leu mice showed reduced dendritic arborization, altered spines, and impaired synaptic transmission and plasticity in the hippocampus. They also exhibited ASD-like phenotypes, including stereotypical behaviors and deficits in social interaction. Moreover, the plasma proBDNF/mBDNF ratio was significantly increased in ASD patients compared to normal children in a case-control study. Thus, deficits in proBDNF to mBDNF conversion in the brain may contribute to ASD-like behaviors, and plasma proBDNF/mBDNF ratio may be a potential biomarker for ASD., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Insect prophenoloxidases (PPOs) are important immunity proteins for defending against the invading pathogens and parasites. As a Type-Ⅲ copper-containing proteins, unlike Homo sapiens tyrosinases, the insect PPOs and most bacterial tyrosinases contain no signal peptides for unknown reason, however they can still be released. To this end, we fused different signal peptides to Drosophila melanogaster PPOs for in vitro and in vivo expression, respectively. We demonstrate that an artificial signal peptide can help PPO secretion in vitro. The secreted PPO appeared larger than wild-type PPO on molecular weight sizes due to glycosylation when expressed in S2 cells. Two asparagine residues for potential glycosylation in PPO1 were identified when a signal peptide was fused. After purification, the glycosylated PPO1 lost zymogen activity. When PPO1 containing a signal peptide was over-expressed in Drosophila larvae, the glycosylation and secretion of PPO1 was detected in vivo. Unlike insect PPO, human tyrosinase needs a signal peptide for protein expression and maintaining enzyme activity. An artificial signal peptide fused to bacterial tyrosinase had no influence on the protein expression and enzyme activity. These Type-Ⅲ copper-containing proteins from different organisms may evolve to perform their specific functions. Intriguingly, our study revealed that the addition of calcium inhibits PPO secretion from the transiently cultured larval hindguts in vitro, indicating that the calcium concentration may regulate PPO secretion. Taken together, insect PPOs can maintain enzyme activities without any signal peptide., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A preclinical model of human adolescent binge drinking, adolescent intermittent ethanol exposure (AIE) recreates the heavy binge withdrawal consummatory patterns of adolescents and has identified the loss of basal forebrain cholinergic neurons as a pathological hallmark of this model. Cholinergic neurons of the nucleus basalis magnocellularis (NbM) that innervate the prefrontal cortex (PFC) are particularly vulnerable to alcohol related neurodegeneration. Target derived neurotrophins (nerve growth factor [NGF] and brain-derived neurotrophic factor [BDNF]) regulate cholinergic phenotype expression and survival. Evidence from other disease models implicates the role of immature neurotrophin, or proneurotrophins, activity at neurotrophic receptors in promoting cholinergic degeneration; however, it has yet to be explored in adolescent binge drinking. We sought to characterize the pro- and mature neurotrophin expression, alongside their cognate receptors and cholinergic markers in an AIE model. Male and female Sprague Dawley rats underwent 5 g/kg 20% EtOH or water gavage on two-day-on, two-day-off cycles from post-natal day 25-57. Rats were sacrificed 2 h, 24 h, or 3 weeks following the last gavage, and tissue were collected for protein measurement. Western blot analyses revealed that ethanol intoxication reduced the expression of BDNF and vesicular acetylcholine transporter (vAChT) in the PFC, while NGF was lower in the NbM of AIE treated animals. During acute alcohol withdrawal, proNGF in the PFC was increased while proBDNF decreased, and in the NbM proBDNF increased while NGF decreased. During AIE abstinence, the expression of neurotrophins, their receptors, and vAChT did not differ from controls in the PFC. In contrast, in the NbM the expression of both NGF and choline acetyltransferase (ChAT) were reduced long-term following AIE. Taken together these findings suggest that AIE alters the expression of proneurotrophins and neurotrophins during intoxication and withdrawal that favor prodegenerative mechanisms by increasing the expression of proNGF and proBDNF, while also reducing NGF and BDNF., (Copyright © 2024 Elsevier Inc. All rights reserved.)

An acute kidney injury (AKI) is the most common complication following cardiac surgery, and can lead to the initiation of continuous renal replacement therapy (CRRT). However, there is still insufficient evidence for when patients should be liberated from CRRT. Proenkephalin A 119-159 (PENK) is a novel biomarker that reflects kidney function independently of other factors. This study investigated whether PENK could guide successful liberation from CRRT. Therefore, we performed a prospective, observational, single-center study at the Medical University of Vienna between July 2022 and May 2023, which included adult patients who underwent cardiac surgery for a cardiopulmonary bypass; patients on preoperative RRT were excluded. The PENK levels were measured at the time of AKI diagnosis and at the initiation of and liberation from CRRT, and were subsequently compared to determine whether the patients were successfully liberated from CRRT. We screened 61 patients with postoperative AKI; 20 patients experienced a progression of AKI requiring CRRT. The patients who were successfully liberated from CRRT had mean PENK levels of 113 ± 95.4 pmol/L, while the patients who were unsuccessfully liberated from CRRT had mean PENK levels of 290 ± 175 pmol/L ( p = 0.018). For the prediction of the successful liberation from CRRT, we found an area under the curve of 0.798 (95% CI, 0.599-0.997) with an optimal threshold value of 126.7 pmol/L for PENK (Youden Index = 0.53, 95% CI, 0.10-0.76) at the time of CRRT liberation (sensitivity = 0.64, specificity = 0.89). In conclusion, PENK is a novel biomarker that has the potential to predict the successful liberation from CRRT for patients with AKI after cardiac surgery.

After injury, mammalian spinal cords develop scars to confine the lesion and prevent further damage. However, excessive scarring can hinder neural regeneration and functional recovery 1,2 . These competing actions underscore the importance of developing therapeutic strategies to dynamically modulate scar progression. Previous research on scarring has primarily focused on astrocytes, but recent evidence has suggested that ependymal cells also participate. Ependymal cells normally form the epithelial layer encasing the central canal, but they undergo massive proliferation and differentiation into astroglia following certain injuries, becoming a core scar component 3-7 . However, the mechanisms regulating ependymal proliferation in vivo remain unclear. Here we uncover an endogenous κ-opioid signalling pathway that controls ependymal proliferation. Specifically, we detect expression of the κ-opioid receptor, OPRK1, in a functionally under-characterized cell type known as cerebrospinal fluid-contacting neuron (CSF-cN). We also discover a neighbouring cell population that expresses the cognate ligand prodynorphin (PDYN). Whereas κ-opioids are typically considered inhibitory, they excite CSF-cNs to inhibit ependymal proliferation. Systemic administration of a κ-antagonist enhances ependymal proliferation in uninjured spinal cords in a CSF-cN-dependent manner. Moreover, a κ-agonist impairs ependymal proliferation, scar formation and motor function following injury. Together, our data suggest a paracrine signalling pathway in which PDYN + cells tonically release κ-opioids to stimulate CSF-cNs and suppress ependymal proliferation, revealing an endogenous mechanism and potential pharmacological strategy for modulating scarring after spinal cord injury., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

We genetically manipulated HaCaT cells, a spontaneously immortalised normal keratinocyte cell line, to stably express two different coloured luciferase reporter genes, driven by interleukin 8 (IL-8) and ubiquitin-C (UBC) promoters, respectively. Subsequently, we generated a three-dimensional (3D) skin-like in vitro composite (SLIC) utilising these cells, with the objective of monitoring bioluminescence emitted from the SLIC. This SLIC was generated on non-woven silica fibre membranes in differentiation medium. Immunohistochemical analyses of skin differentiation markers in the SLIC revealed the expression of keratins 2 and 10, filaggrin, and involucrin, indicating mature skin characteristics. This engineered SLIC was employed for real-time bioluminescence monitoring, allowing the assessment of time- and dose-dependent responses to UV stress, as well as to hydrophilic and hydrophobic chemical loads. Notably, evaluation of responses to hydrophobic substances has been challenging with conventional 2D cell culture methods, suggesting the need for a new approach, which this technology could address. Our observations suggest that engineered SLIC with constitutively expressing reporters driven by selected promoters which are tailored to specific objectives, significantly facilitates assays exploring the physiological functions of skin cells based on genetic response mechanisms. It also highlights new avenues for evaluating the physiological impacts of various compounds designed for topical application to human skin., (© 2024 The Author(s). The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

A propeptide is removed from a precursor protein to generate its active or mature form. Propeptides play essential roles in protein folding, transportation, and activation and are present in about 2.3% of reviewed proteins in the UniProt database. They are often found in secreted or membrane-bound proteins including proteolytic enzymes, hormones, and toxins. We identified a variety of globular and nonglobular Pfam domains in protein sequences designated as propeptides, some of which form intramolecular interactions with other domains in the mature proteins. Propeptide-containing enzymes mostly function as proteases, as they are depleted in other enzyme classes such as hydrolases acting on DNA and RNA, isomerases, and lyases. We applied AlphaFold to generate structural models for over 7000 proteins with propeptides having no less than 20 residues. Analysis of residue contacts in these models revealed conformational changes for over 300 proteins before and after the cleavage of the propeptide. Examples of conformation change occur in several classes of proteolytic enzymes in the families of subtilisins, trypsins, aspartyl proteases, and thermolysin-like metalloproteases. In most of the observed cases, cleavage of the propeptide releases the constraints imposed by the covalent bond between the propeptide and the mature protein, and cleavage enables stronger interactions between the propeptide and the mature protein. These findings suggest that post-cleavage propeptides could play critical roles in regulating the activity of mature proteins., (© 2024 The Authors. Proteins: Structure, Function, and Bioinformatics published by Wiley Periodicals LLC.)

The plasminogen activator inhibitor-1 (PAI-1)→mature brain-derived neurotrophic factor (mBDNF) pathway plays a pivotal role in the conversion of probrain-BDNF (ProBDNF) to mBDNF, but its clinical relevance in patients with alcohol use disorder (AUD) remains unknown. Enzyme-linked immunosorbent assays were used to examine the relevant protein levels of components of the PAI-1→mBDNF pathway in plasma samples from three groups of subjects, and statistical analysis was performed using analysis of variance (ANOVA) and one-way repeated-measures ANOVA. Our findings revealed significant alterations induced by alcohol. (1) AUD was associated with significant decreases in tissue plasminogen activator (tPA), mBDNF, and tropomyosin receptor kinase B (TrkB); significant increases in PAI-1, ProBDNF, and P75 neurotrophin receptor (P75NTR); and inhibited conversion of ProBDNF to mBDNF. (2) Following abstinence, the levels of tPA, mBDNF, and TrkB in the AUD group significantly increased, whereas the levels of PAI-1, ProBDNF, and P75NTR significantly decreased, promoting the conversion of ProBDNF to mBDNF. These clinical outcomes collectively suggest that AUD inhibits the conversion of ProBDNF to mBDNF and that abstinence reverses this process. The PAI-1→mBDNF cleavage pathway is hypothesized to be associated with AUD and abstinence treatment., (© 2024. The Author(s).)

Background: Considering the increasing worldwide prevalence of inflammatory bowel disease (IBD), the early diagnosis of this disease is extremely important. However, non-invasive diagnostic methods remain limited, while invasive techniques are the most commonly used in daily practice. Therefore, there is a serious need to find new non-invasive biomarkers of IBD., Methods: The serum profiles of occludin, claudin-2, and zonulin were assessed in IBD patients using the ELISA method. The levels of the analyzed biomarkers were measured before and after a year of anti-inflammatory treatment, which was a tumor necrosis factor α (TNF-α) inhibitor (adalimumab) in patients with ulcerative colitis (UC) and conventional therapy in patients with Crohn's disease (CD)., Results: In IBD patients, the serum level of occludin ( p < 0.001) decreased compared to healthy individuals, while the level of claudin-2 ( p < 0.001) increased. Additionally, zonulin ( p < 0.01) concentration increased in CD patients compared to the control group. The highest diagnostic ability was presented by occludin measurements with the area under the curve (AUC) of 0.959 (95% CI 0.907-1) in UC and 0.948 (95% CI 0.879-1) in CD. Claudin-2 also demonstrated very good ability in diagnosing UC and CD with AUC values of 0.864 (95% CI 0.776-0.952) and 0.896 (95% CI 0.792-0.999), respectively. The ability of zonulin to diagnose CD was estimated as good with an AUC of 0.74 (95% CI 0.598-0.881). Moreover, a significant correlation was identified between C-reactive protein (CRP), claudin-2 (r = -0.37; p < 0.05), and zonulin (r = -0.44; p < 0.05) in UC patients. Treatment with adalimumab improved the level of occludin, claudin-2, and zonulin in UC patients, while anti-inflammatory conventional therapy decreased the concentration of zonulin in CD., Conclusions: Occludin and claudin-2 measurements present significant utility in diagnosing both UC and CD, while zonulin assessments may be useful in CD diagnosis. Additionally, claudin-2 and zonulin measurements may be helpful in evaluating the intensity of the inflammatory process. Anti-TNF-α treatment improved the value of occludin, claudin-2, and zonulin, indicating its beneficial effect on the integrity of tight junctions in UC.

Basal forebrain cholinergic neurons (BFCNs) extend long projections to multiple regions in the brain to regulate cognitive functions. Degeneration of BFCNs is seen with aging, after brain injury, and in neurodegenerative disorders. An increase in the amount of the immature proform of nerve growth factor (proNGF) in the cerebral cortex results in retrograde degeneration of BFCNs through activation of proNGF receptor p75 NTR . Here, we investigated the signaling cascades initiated at the axon terminal that mediate proNGF-induced retrograde degeneration. We found that local axonal protein synthesis and retrograde transport mediated proNGF-induced degeneration initiated from the axon terminal. Analysis of the nascent axonal proteome revealed that proNGF stimulation of axonal terminals triggered the synthesis of numerous proteins within the axon, and pathway analysis showed that amyloid precursor protein (APP) was a key upstream regulator in cultured BFCNs and in mice. Our findings reveal a functional role for APP in mediating BFCN axonal degeneration and cell death induced by proNGF.

To explore whether the intestinal damage of yak colibacillosis resulted from the regulation of Zonulin expression by its pathogenic bacteria, the overexpression and interference plasmids of Zonulin were designed and cultured in Tranwell after cell transfection. Then qRT-PCR and Western blot were used to detect the results of cell transfection, 200 mL 1×105 CFU/mL E.coli O78 was added for 4 hours, transmembrane resistance was measured by transmembrane resistance meter, FD4 fluorescence concentration in the lower chamber was detected by enzyme labeling instrument, bacterial translocation was measured by CFU counting method, and epithelial mucin (MUC1, MUC2) and tight junction protein (FABP2, Occludin, ZO-1) were detected by qRT-PCR., Results: The Zonulin gene overexpression and knockout cell lines were successfully constructed, the TEER value of the barrier of Zonulin overexpression cell lines began to decrease at 1 h after the addition of E.coli O78 and reached the lowest value at 4 h, and the TEER value of Zonulin interference cell lines decreased within 1-4 h after the addition of E.coli O78. At 4 h, the FD4 passing capacity of Zonulin overexpression cell lines was significantly higher than that of interfering cell lines, reaching twice as much as siRNA-1. The amount of bacterial translocation in overexpressed cell lines increased rapidly within 1-4 h, and the concentration of E.coli in the lower chamber was significantly higher than that in the siRNA-1 group at 4 h, but there was no significant change in the siRNA-1 group in the 1-4 h. There was no significant change in the mRNA level of MUC1 in Zonulin overexpression and interference cell lines after the addition of E.coli O78. In the overexpression group, the mRNA levels of MUC2, Occludin, and ZO-1 were significantly decreased, and the mRNA level of FABP2 was increased considerably. These results suggest stimulate epithelial cells to secrete Zonulin protein. Many Zonulin proteins regulate the opening of tight junction structures, reduce the transmembrane resistance of the cell barrier, and improve the permeability of the cell barrier and the amount of bacterial translocation., 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 © 2024 Ren, Shi, Chang, Zhang, Wang, Liu, Sang, Dong and Wu.)

CD8+ T cells destroy insulin-producing pancreatic β cells in type 1 diabetes through HLA class I-restricted presentation of self-antigens. Combinatorial peptide library screening was used to produce a preferred peptide recognition landscape for a patient-derived T cell receptor (TCR) that recognized the preproinsulin-derived (PPI-derived) peptide sequence LWMRLLPLL in the context of disease risk allele HLA A*24:02. Data were used to generate a strong superagonist peptide, enabling production of an autoimmune HLA A*24:02-peptide-TCR structure by crystal seeding. TCR binding to the PPI epitope was strongly focused on peptide residues Arg4 and Leu5, with more flexibility at other positions, allowing the TCR to strongly engage many peptides derived from pathogenic bacteria. We confirmed an epitope from Klebsiella that was recognized by PPI-reactive T cells from 3 of 3 HLA A*24:02+ patients. Remarkably, the same epitope selected T cells from 7 of 8 HLA A*24+ healthy donors that cross-reacted with PPI, leading to recognition and killing of HLA A*24:02+ cells expressing PPI. These data provide a mechanism by which molecular mimicry between pathogen and self-antigens could have resulted in the breaking of self-tolerance to initiate disease.

Preptin, a 34-amino acid peptide derived from pro-IGF2, is believed to influence various physiological processes, including insulin secretion and the regulation of bone metabolism. Despite its recognized involvement, the precise physiological role of preptin remains enigmatic. To address this knowledge gap, we synthesized 16 analogs of preptin, spanning a spectrum from full-length forms to fragments, and conducted comprehensive comparative activity evaluations alongside native human, mouse and rat preptin. Our study aimed to elucidate the physiological role of preptin. Contrary to previous indications of broad biological activity, our thorough analyses across diverse cell types revealed no significant biological activity associated with preptin or its analogs. This suggests that the associations of preptin with various diseases or tissue-specific abundance fluctuations may be influenced by factors beyond preptin itself, such as higher levels of IGF2 or IGF2 proforms present in tissues. In conclusion, our findings challenge the conventional notion of preptin as an isolated biologically active molecule and underscore the complexity of its interactions within biological systems. Rather than acting independently, the observed effects of preptin may arise from experimental conditions, elevated preptin concentrations, or interactions with related molecules such as IGF2., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Mrázková et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objective: The aim of our study was to investigate whether a 1-month-long milk-free diet results in a reduction in faecal calprotectin (FC) and faecal-zonulin-related proteins (FZRP) in children with milk-protein-induced allergic proctocolitis (MPIAP)., Materials and Methods: This is a single-centre, prospective, observational cohort study involving 86 infants with MPIAP, aged 1-3 months, and 30 healthy controls of the same age. The FC and FZRP were marked using the ELISA method (IDK ® Calprotectin or Zonulin ELISA Kit, Immunodiagnostik AG, Bensheim, Germany). The diagnosis of MPIAP was confirmed with an open milk challenge test., Results: FFC and FZRP proved useful in evaluating MPIAP treatment with a milk-free diet, and the resolution of allergic symptoms and a significant ( p = 0.0000) decrease in the concentrations of both biomarkers were observed after 4 weeks on the diet. The FC and FZRP concentrations were still higher than in the control group. A high variability of FC concentrations was found in all the study groups. An important limitation is the phenomenon of FZRP not being produced in all individuals, affecting one in five infants., Conclusions: FC and FZRP can be used to monitor the resolution of colitis in infants with MPIAP treated with a milk-free diet, indicating a slower resolution of allergic inflammation than of allergic symptoms. The diagnosis of MPIAP on the basis of FC concentrations is subject to considerable error, due to the high individual variability of this indicator. FZRP is a better parameter, but this needs further research, as these are the first determinations in infants with MPIAP.

Parkinson's disease is associated with gastrointestinal (GI) dysfunction, including constipation symptoms and abnormal intestinal permeability and inflammation. A Mediterranean diet (MediDiet) may aid in disease management . This parallel, randomized, controlled trial in people with Parkinson's (PwP) and constipation symptoms compared a MediDiet against standard of care on change in constipation symptoms, dietary intake, and fecal zonulin and calprotectin concentrations as markers of intestinal permeability and inflammation, respectively. Participants were randomized to either standard of care for constipation (control; n = 17, 65.1 ± 2.2 years) or a MediDiet plus standard of care ( n = 19, 68.8 ± 1.4 years) for 8 weeks. Constipation scores decreased with both interventions ( p < 0.01), but changes from baseline were not different between groups (MediDiet, -0.5 [-1.0, 0]; control, -0.8 [-1.0, 0.2]; median [25th, 75th]; p = 0.60). The MediDiet group had a higher intake of dietary fiber at week 4 than the control group (13.1 ± 0.7 g/1000 kcal vs. 9.8 ± 0.7 g/1000 kcal; p < 0.001). No differences in fecal zonulin were observed between groups ( p = 0.33); however, fecal calprotectin tended to be lower in the MediDiet group at week 8 (45.8 ± 15.1 µg/g vs. 93.9 ± 26.8 µg/g; p = 0.05). The MediDiet and standard interventions reduced constipation symptoms; however, the MediDiet provided additional benefit of increased dietary fiber intake and less intestinal inflammation.

Feeding behaviour is influenced by two primary factors: homoeostatic needs driven by hunger and hedonic desires for pleasure even in the absence of hunger. While efficient homoeostatic feeding is vital for survival, excessive hedonic feeding can lead to adverse consequences such as obesity and metabolic dysregulations. However, the neurobiological mechanisms that orchestrate homoeostatic versus hedonic food consumption remain largely unknown. Here we show that GABAergic proenkephalin (Penk) neurons in the diagonal band of Broca (DBB) of male mice respond to food presentation. We further demonstrate that a subset of DBB Penk neurons that project to the paraventricular nucleus of the hypothalamus are preferentially activated upon food presentation during fasting periods and transmit a positive valence to facilitate feeding. On the other hand, a separate subset of DBB Penk neurons that project to the lateral hypothalamus are preferentially activated when detecting a high-fat high-sugar (HFHS) diet and transmit a negative valence to inhibit food consumption. Notably, when given free choice of chow and HFHS diets, mice with the whole DBB Penk population ablated exhibit reduced consumption of chow but increased intake of the HFHS diet, resulting in accelerated development of obesity and metabolic disturbances. Together, we identify a molecularly defined neural population in male mice that is crucial for the maintenance of energy balance by facilitating homoeostatic feeding while suppressing hedonic overeating., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Background: Integrins are upregulated on endothelial cells and T-lymphocytes in autoimmune thyroid disease (AITD), potentially contributing to immune response localization. The role of integrins on B-cells in AITD remains unclear., Methods: Peripheral blood samples were collected from healthy controls (n = 56), patients with Graves' disease (GD) (n = 37) and Hashimoto's thyroiditis (HT) (n = 52). Ultrasound-guided fine-needle aspiration (FNA) of the thyroid was performed in patients with non-autoimmune thyroid disease (nAITD) (n = 19), GD (n = 11), and HT (n = 40). Integrins α4β7, α4β1, and αEβ7 in B cells were measured by flow cytometry. Serum zonulin levels were quantified via ELISA. Associations of integrins on B cells with thyroid hormones, thyroid autoantibodies, AITD duration, and zonulin were analyzed., Results: HT patients exhibited lower α4β7 and higher α4β1 expression on B cells compared to healthy controls and GD patients. While α4β7 was predominant on circulating B cells, the dominant integrin expressed on intrathyroidal B cells varied with specific thyroid diseases. In GD patients, α4β7 and α4β1 expression on circulating B cells correlated positively and negatively with thyroid function and thyroid stimulating immunoglobulins (TSI) levels, respectively. Intrathyroidal α4β1 + B cells positively correlated with TSH levels in HT patients. Additionally, serum zonulin was elevated in HT patients, and intrathyroidal α4β7 + B cells and α4β1 + B cells correlated negatively and positively with zonulin levels, respectively. Integrin αEβ7 on B cells showed no significant association with AITD., Conclusion: Integrins expressed on B cells potentially play a role in the pathogenesis of AITD and might serve as immune biomarkers for the disease., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Benvitimod has been successfully used in the treatment of psoriasis and atopic dermatitis (AD). However, the mechanism remains to be clarified. We aim to assess the effects of benvitimod on MC903-induced dermatitis in mice and to investigate the effects of benvitimod on filaggrin (FLG), involucrin (IVL), and loricrin (LOR) expressions and possible mechanism. MC903-induced mouse AD model was used to evaluate the effects of benvitimod. Filaggrin, involucrin, and loricrin protein and mRNA expressions in lesions of mice dermatitis were measured by Western blot and quantitative real-time PCR. In vitro, normal human epidermal keratinocytes (NHEKs) were cultured and benvitimod was used to treat NHEKs primed with IL-4 and IL-13. Then AHR and OVOL1 in NHEKs were knocked down to evaluate the role of AHR and OVOL1 in the effects of benvitimod. Topical treatment of benvitimod repaired skin barrier and alleviated skin inflammation in mouse AD model. This effect was inhibited by pretreatment with an AHR antagonist. Benvitimod upregulated the filaggrin, involucrin, and loricrin expressions in lesions of mouse AD model. In addition, benvitimod upregulated the filaggrin, involucrin, and loricrin expressions in NHEKs. Knockdown of AHR or OVO-like (OVOL)1 abrogated the upregulation of filaggrin, involucrin, and loricrin induced by benvitimod. Benvitimod attenuated MC903-induced mouse dermatitis and upregulated filaggrin, involucrin, and loricrin expressions via AHR-OVOL1 axis., (© 2024. The Author(s).)

Many patients with irritable bowel syndrome (IBS) have a compromised intestinal barrier associated with low-grade inflammation. Polyunsaturated fatty acids (PUFAs) are potential mediators of inflammation: omega-6 PUFAs are pro-inflammatory, while omega-3 PUFAs are antioxidant and anti-inflammatory. Zonulin is a potential biomarker for small intestinal permeability (s-IP). This study investigated the relationship between PUFAs and gastrointestinal (GI) barrier integrity in IBS patients with predominant diarrhea (IBS-D). We evaluated GI barrier function indicators in the urine and bloodstream and erythrocyte membrane PUFA composition in 38 IBS-D patients (5 men, 33 women, 44.11 ± 1.64 years), categorized at baseline by fecal zonulin levels into high (≥107 ng/mL, H-FZ) and normal (<107 ng/mL N-FZ) groups. Evaluations were conducted prior to and following a 12-week diet low in FODMAPs (LFD). At baseline, H-FZ patients had s-IP significantly higher than the reference value, lower n -3 PUFAs levels, and higher n -6/ n -3 PUFAs and arachidonic acid (AA) to eicosapentaenoic acid (EPA) ratios than N-FZ. After LFD, H-FZ patients showed significant increases in n -3 PUFAs levels; decreases in n -6 PUFAs, n -6/ n -3 PUFAs and AA/EPA ratios; and improved s-IP. The n -6/ n -3 PUFAs ratio positively correlated with fecal zonulin levels in all subjects. These findings highlight the relationship between PUFAs and the intestinal barrier, suggesting their role in IBS-D pathophysiology and confirming the positive effects of LFD in managing IBS-D.

CD4 + CD25 + Foxp3 + regulatory T cells (Treg) have been implicated in pain modulation in various inflammatory conditions. However, whether Treg cells hamper pain at steady state and by which mechanism is still unclear. From a meta-analysis of the transcriptomes of murine Treg and conventional T cells (Tconv), we observe that the proenkephalin gene ( Penk ), encoding the precursor of analgesic opioid peptides, ranks among the top 25 genes most enriched in Treg cells. We then present various evidence suggesting that Penk is regulated in part by members of the Tumor Necrosis Factor Receptor (TNFR) family and the transcription factor Basic leucine zipper transcription faatf-like (BATF). Using mice in which the promoter activity of Penk can be tracked with a fluorescent reporter, we also show that Penk expression is mostly detected in Treg and activated Tconv in non-inflammatory conditions in the colon and skin. Functionally, Treg cells proficient or deficient for Penk suppress equally well the proliferation of effector T cells in vitro and autoimmune colitis in vivo. In contrast, inducible ablation of Penk in Treg leads to heat hyperalgesia in both male and female mice. Overall, our results indicate that Treg might play a key role at modulating basal somatic sensitivity in mice through the production of analgesic opioid peptides., Competing Interests: NA, MP, JN, JS, AA, WL, MF, LC, MN, AC, MD, NB, GD, CP, GM No competing interests declared, (© 2024, Aubert et al.)

Cerebral palsy (CP) results in non-progressive damage to the central nervous system, leading to functional disorders of the gastrointestinal tract and requiring enteral nutrition via gastrostomy in some patients. The aim of the study was to assess the impact of enteral nutrition on intestinal inflammation expressed by stool calprotectin and intestinal permeability determined by fecal zonulin and IFABP, and to determine whether CP affects these parameters. The study group consisted of 30 children with CP, fed enterally (Cerebral Palsy Enteral Nutrition-CPEN), and two reference groups: 24 children with CP, fed orally with a standard diet (CPC-Cerebral Palsy Controls) and 24 healthy children (HC-healthy controls). The differences between these groups and between the combined CP groups (CPG and CPEN + CPC) and HC were analyzed. Fecal zonulin, calprotectin, and intestinal fatty acid-binding protein 2 (IFABP2) levels were determined by ELISA. The concentrations of fecal calprotectin and zonulin were significantly higher in the CPEN group than in the CPC group ( p = 0.012, p = 0.025). When comparing the CPG ( n = 53) with the HC group ( n = 24), statistically significant differences were observed for calprotectin ( p = 0.000018, higher in the CPG) and IFABP ( p = 0.021, higher in HC). Enteral nutrition was associated in our cohort with increased fecal calprotectin and zonulin. Children with cerebral palsy presented with increased fecal calprotectin but not increased intestinal permeability expressed by stool zonulin.

Background: Psoriasis is a noncontagious auto-inflammatory chronic skin disease. So far, some of the inflammatory genes were upregulated in mouse model of psoriasis. This study examined changes in skin mRNA expression of L-kynureninase ( Kynu ), cathelicidin antimicrobial peptide ( Camp ), beta-defensin 2 ( Defb2 ), and proenkephalin ( Penk ) in a mouse model of imiquimod-induced psoriasis., Materials and Methods: Tree groups of C57BL/6 female mice were allocated. The imiquimod (IMQ) cream was administered to the mice dorsal skin of the two groups to induce psoriatic inflammation. In the treatment group, IMQ was administered 10 min after hydrogel-containing M7 anti-IL-17A aptamer treatment. Vaseline (Vas) was administered to the negative control group. The psoriatic skin lesions were evaluated based on the psoriasis area severity index (PASI) score, histopathology, and mRNA expression levels of Kynu , Camp , Defb2 , and Penk using real-time PCR. In order to assess the systemic response, the spleen and lymph node indexes were also evaluated., Results: The PASI and epidermal thickness scores were 6.01 and 1.96, respectively, in the IMQ group, and they significantly decreased after aptamer administration to 1.15 and 0.90, respectively ( P < 0.05). Spleen and lymph node indexes showed an increase in the IMQ group, followed by a slight decrease after aptamer treatment ( P > 0.05). Additionally, the mRNA expression levels of Kynu , Defb2 , Camp , and Penk genes in the IMQ-treated region showed a significant 2.70, 4.56, 3.29, and 2.61-fold increase relative to the Vas mice, respectively ( P < 0.05). The aptamer-treated region exhibited a significant decrease in these gene expression levels ( P < 0.05). A positive correlation was found between Kynu , Penk , and Camp expression levels and erythema, as well as Camp expression with PASI, scaling, and thickness ( P < 0.05)., Conclusion: According to our results, it seems that Kynu , Camp , and Penk can be considered appropriate markers for the evaluation of psoriasis in IMQ-induced psoriasis. Also, the anti-IL-17 aptamer downregulated these important genes in this mouse model., Competing Interests: The authors declare that there are no conflicts of interest regarding the publication of this article., (Copyright © 2024 Zahra Emami et al.)

Progerin, the protein that causes Hutchinson-Gilford progeria syndrome, triggers nuclear membrane (NM) ruptures and blebs, but the mechanisms are unclear. We suspected that the expression of progerin changes the overall structure of the nuclear lamina. High-resolution microscopy of smooth muscle cells (SMCs) revealed that lamin A and lamin B1 form independent meshworks with uniformly spaced openings (~0.085 µm 2 ). The expression of progerin in SMCs resulted in the formation of an irregular meshwork with clusters of large openings (up to 1.4 µm 2 ). The expression of progerin acted in a dominant-negative fashion to disrupt the morphology of the endogenous lamin B1 meshwork, triggering irregularities and large openings that closely resembled the irregularities and openings in the progerin meshwork. These abnormal meshworks were strongly associated with NM ruptures and blebs. Of note, the progerin meshwork was markedly abnormal in nuclear blebs that were deficient in lamin B1 (~50% of all blebs). That observation suggested that higher levels of lamin B1 expression might normalize the progerin meshwork and prevent NM ruptures and blebs. Indeed, increased lamin B1 expression reversed the morphological abnormalities in the progerin meshwork and markedly reduced the frequency of NM ruptures and blebs. Thus, progerin expression disrupts the overall structure of the nuclear lamina, but that effect-along with NM ruptures and blebs-can be abrogated by increased lamin B1 expression., Competing Interests: Competing interests statement:The authors declare no competing interest.

The "KNDy neurons" located in the hypothalamic arcuate nucleus (ARC) of mammals are known to co-express kisspeptin, neurokinin B (NKB), and dynorphin (DYN), and have been identified as key mediators of the feedback regulation of steroid hormones on gonadotropin-releasing hormone (GnRH). However, in birds, the genes encoding kisspeptin and its receptor GPR54 are genomic lost, leaving unclear mechanisms for feedback regulation of GnRH by steroid hormones. Here, the genes tachykinin 3 (TAC3) and prodynorphin (PDYN) encoding chicken NKB and DYN neuropeptides were successfully cloned. Temporal expression profiling indicated that TAC3, PDYN and their receptor genes (TACR3, OPRK1) were mainly expressed in the hypothalamus, with significantly higher expression at 30W than at 15W. Furthermore, overexpression or interference of TAC3 and PDYN can regulate the GnRH mRNA expression. In addition, in vivo and in vitro assays showed that estrogen (E2) could promote the mRNA expression of TAC3, PDYN, and GnRH, as well as the secretion of GnRH/LH. Mechanistically, E2 could dimerize the nuclear estrogen receptor 1 (ESR1) to regulate the expression of TAC3 and PDYN, which promoted the mRNA and protein expression of GnRH gene as well as the secretion of GnRH. In conclusion, these results revealed that E2 could regulate the GnRH expression through TAC3 and PDYN systems, providing novel insights for reproductive regulation in chickens., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

As discovery of cellular diversity in the brain accelerates, so does the need for tools that target cells based on multiple features. Here we developed Conditional Viral Expression by Ribozyme Guided Degradation (ConVERGD), an adeno-associated virus-based, single-construct, intersectional targeting strategy that combines a self-cleaving ribozyme with traditional FLEx switches to deliver molecular cargo to specific neuronal subtypes. ConVERGD offers benefits over existing intersectional expression platforms, such as expanded intersectional targeting with up to five recombinase-based features, accommodation of larger and more complex payloads and a vector that is easy to modify for rapid toolkit expansion. In the present report we employed ConVERGD to characterize an unexplored subpopulation of norepinephrine (NE)-producing neurons within the rodent locus coeruleus that co-express the endogenous opioid gene prodynorphin (Pdyn). These studies showcase ConVERGD as a versatile tool for targeting diverse cell types and reveal Pdyn-expressing NE + locus coeruleus neurons as a small neuronal subpopulation capable of driving anxiogenic behavioral responses in rodents., (© 2024. The Author(s), under exclusive licence to Springer Nature America, Inc.)

Diverse computational approaches have been widely used to assist in designing antimicrobial peptides with enhanced activities. This tactic has also been used to address the need for new treatment alternatives to combat resistant bacterial infections. Herein, we have designed eight variants from a natural peptide, pro-adrenomedullin N-terminal 20 peptide (PAMP), using an in silico pattern insertion approach, the Joker algorithm. All the variants show an α-helical conformation, but with differences in the helix percentages according to circular dichroism (CD) results. We found that the C-terminal portion of PAMP may be relevant for its antimicrobial activities, as revealed by the molecular dynamics, CD, and antibacterial results. The analogs showed variable antibacterial potential, but most were not cytotoxic. Nevertheless, PAMP2 exhibited the most potent activities against human and animal-isolated bacteria, showing cytotoxicity only at a substantially higher concentration than its minimal inhibitory concentration (MIC). Our results suggest that the enhanced activity in the profile of PAMP2 may be related to their particular physicochemical properties, along with the adoption of an amphipathic α-helical arrangement with the conserved C-terminus portion. Finally, the peptides designed in this study can constitute scaffolds for the design of improved sequences., (© 2024 John Wiley & Sons Ltd.)

ATP has recently been reconsidered as a molecule with functional properties which go beyond its recognized role of the energetic driver of the cell. ATP has been described as an allosteric modulator as well as a biological hydrotrope with anti-aggregation properties in the crowded cellular environment. The role of ATP as a modulator of the homeostasis of the neurotrophins (NTs), a growth factor protein family whose most known member is the nerve growth factor (NGF), has been investigated. The modulation of NTs by small endogenous ligands is still a scarcely described area, with few papers reporting on the topic, and very few reports on the molecular determinants of these interactions. However, a detailed atomistic description of the NTs interaction landscape is of urgent need, aiming at the identification of novel molecules as potential therapeutics and considering the wide range of potential pharmacological applications for NGF and its family members. This mini-review will focus on the unique cartography casting the interactions of the endogenous ligand ATP, in the interaction with NGF as well as with its precursor proNGF. These interactions revealed interesting features of the ATP binding and distinct differences in the binding mode between the highly structured mature NGF and its precursor, proNGF, which is characterized by an intrinsically unstructured domain. The overview on the recent available data will be presented, together with the future perspectives on the field., (© 2024 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

(1) Background: The effects of short-term social isolation during adulthood have not yet been fully established in rats behaviourally, and not at all transcriptomically in the medial prefrontal cortex (mPFC). (2) Methods: We measured the behavioural effects of housing adult male rats in pairs or alone for 10 days. We also used RNA sequencing to measure the accompanying gene expression alterations in the mPFC of male rats. (3) Results: The isolated animals exhibited reduced sociability and social novelty preference, but increased social interaction. There was no change in their aggression, anxiety, or depression-like activity. Transcriptomic analysis revealed a differential expression of 46 genes between the groups. The KEGG pathway analysis showed that differentially expressed genes are involved in neuroactive ligand-receptor interactions, particularly in the dopaminergic and peptidergic systems, and addiction. Subsequent validation confirmed the decreased level of three altered genes: regulator of G protein signalling 9 (Rgs9), serotonin receptor 2c (Htr2c), and Prodynorphin (Pdyn), which are involved in dopaminergic, serotonergic, and peptidergic function, respectively. Antagonizing Htr2c confirmed its role in social novelty discrimination. (4) Conclusions: Social homeostatic regulations include monoaminergic and peptidergic systems of the mPFC.

The strength of inhibitory neurotransmission depends on intracellular neuronal chloride concentration, primarily regulated by the activity of cation-chloride cotransporters NKCC1 (Sodium-Potassium-Chloride Cotransporter 1) and KCC2 (Potassium-Chloride Cotransporter 2). Brain-derived neurotrophic factor (BDNF) influences the functioning of these co-transporters. BDNF is synthesized from precursor proteins (proBDNF), which undergo proteolytic cleavage to yield mature BDNF (mBDNF). While previous studies have indicated the involvement of BDNF signaling in the activity of KCC2, its specific mechanisms are unclear. We investigated the interplay between both forms of BDNF and chloride homeostasis in rat hippocampal neurons and in utero electroporated cortices of rat pups, spanning the behavioral, cellular, and molecular levels. We found that both pro- and mBDNF play a comparable role in immature neurons by inhibiting the capacity of neurons to extrude chloride. Additionally, proBDNF increases the endocytosis of KCC2 while maintaining a depolarizing shift of E GABA in maturing neurons. Behaviorally, proBDNF-electroporated rat pups in the somatosensory cortex exhibit sensory deficits, delayed huddling, and cliff avoidance. These findings emphasize the role of BDNF signaling in regulating chloride transport through the modulation of KCC2. In summary, this study provides valuable insights into the intricate interplay between BDNF, chloride homeostasis, and inhibitory synaptic transmission, shedding light on the underlying cellular mechanisms involved.

Background: Palmoplantar pustulosis (PPP) and pompholyx are chronic diseases characterized by pustules and vesicles on the palms and soles. These disorders often have similar clinicopathological features, which lead to diagnostic difficulties. We aimed to investigate the expression patterns of keratins and involucrin in PPP and pompholyx using immunohistochemical staining., Methods: Skin biopsies from patients with PPP (n = 40) and pompholyx (n = 22) were immunohistochemically analyzed for Keratin 5, 9, 14, and involucrin expression., Results: K5 expression was higher in PPP than in pompholyx, with diffusely positive expression in the basal, spinous, and granular layers. K14 expression did not differ between groups. K9 expression was observed near the pompholyx vesicle (P = 0.014) and stratum spinosum (P < 0.001) but was almost absent around PPP pustules. Involucrin expression was diffused around the PPP pustules and partially around the pompholyx vesicles, but without statistical significance (P = 0.123). Involucrin expression was elevated in the basal layer of the PPP compared with that in the pompholyx (P = 0.023)., Conclusion: PPP and pompholyx exhibited distinctive differentiation in the expression of K5, K9, and involucrin., (© 2024 the International Society of Dermatology.)

The effects of the administration of the opioid agonist, morphine, on plasma and tissue concentrations of Met-enkephalin were determined in 14 wk old female chickens. In addition, effects of morphine on proenkephalin (PENK) expression were examined. Plasma concentrations of Met-enkephalin were reduced 10 minutes after morphine administration. Plasma concentrations of peptides that contain Met-enkephalin motifs were decreased 30 minutes after morphine administration. Tissue concentrations of Met-enkephalin tended to be depressed following morphine administration. Adrenal concentrations of PENK peptides containing Met-enkephalin motifs were decreased in chickens challenged with morphine. Expression of PENK in the anterior pituitary gland and adrenal glands were decreased in morphine treated compared to control pullets. In contrast, plasma concentrations of corticosterone were elevated 10 min after morphine treatment. Morphine also induced changes in mu (µ) opioid receptors and delta (δ) opioid receptors in both anterior pituitary tissue and adrenal tissues., (Copyright © 2024. Published by Elsevier Inc.)

The interleukin (IL)-1 family of cytokines plays a pivotal role in immune responses. Among the members of IL-1 family, IL-1β is synthesized as an inactive precursor (pro-IL-1β) and becomes active upon cleavage, which is typically facilitated by inflammasomes through caspase-1. In our research, we explored the potential role of caspase-3 in the cleavage of pro-IL-1β and found that caspase-3 cleaves pro-IL-1β, specifically at Asp26. Moreover, we found that in the absence of caspase-3 cleavage, the release of active IL-1β via the inflammasome is increased. Our study introduces pro-IL-1β as a new substrate for caspase-3 and suggests that caspase-3-mediated cleavage has the potential to suppress IL-1β-mediated inflammatory responses., (© 2024 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.)

Pre-proenkephalin 1 (Penk1) is a pro-neuropeptide that belongs to the typical opioid peptide's family, having analgesic properties. We previously found Penk1 to be the most downregulated gene in a whole gene profiling analysis performed in osteoblasts subjected to microgravity as a model of mechanical unloading. In this work, Penk1 downregulation was confirmed in the bones of two in vivo models of mechanical unloading: tail-suspended and botulinum toxin A (botox)-injected mice. Consistently, in the sera from healthy volunteers subjected to bed rest, we observed an inverse correlation between PENK1 and bed rest duration. These results prompted us to investigate a role for this factor in bone. Penk1 was highly expressed in mouse bone, but its global deletion failed to impact bone metabolism in vivo. Indeed, Penk1 knock out (Penk1 -/- ) mice did not show an overt bone phenotype compared to the WT littermates. Conversely, in vitro Penk1 gene expression progressively increased during osteoblast differentiation and its transient silencing in mature osteoblasts by siRNAs upregulated the transcription of the Sost1 gene encoding sclerostin, and decreased Wnt3a and Col1a1 mRNAs, suggesting an altered osteoblast activity due to an impairment of the Wnt pathway. In line with this, osteoblasts treated with the Penk1 encoded peptide, Met-enkephalin, showed an increase of Osx and Col1a1 mRNAs and enhanced nodule mineralization. Interestingly, primary osteoblasts isolated from Penk1 -/- mice showed lower metabolic activity, ALP activity, and nodule mineralization, as well as a lower number of CFU-F compared to osteoblasts isolated from WT mice, suggesting that, unlike the transient inhibition, the chronic Penk1 deletion affects both osteoblast differentiation and activity. Taken together, these results highlight a role for Penk1 in the regulation of the response of the bone to mechanical unloading, potentially acting on osteoblast differentiation and activity in a cell-autonomous manner., (© 2024. The Author(s).)

Background: Leaf variegation is an intriguing phenomenon observed in many plant species. However, questions remain on its mechanisms causing patterns of different colours. In this study, we describe a tomato plant detected in an M 2 population of EMS mutagenised seeds, showing variegated leaves with sectors of dark green (DG), medium green (MG), light green (LG) hues, and white (WH). Cells and tissues of these classes, along with wild-type tomato plants, were studied by light, fluorescence, and transmission electron microscopy. We also measured chlorophyll a/b and carotene and quantified the variegation patterns with a machine-learning image analysis tool. We compared the genomes of pooled plants with wild-type-like and mutant phenotypes in a segregating F 2 population to reveal candidate genes responsible for the variegation., Results: A genetic test demonstrated a recessive nuclear mutation caused the variegated phenotype. Cross-sections displayed distinct anatomy of four-leaf phenotypes, suggesting a stepwise mesophyll degradation. DG sectors showed large spongy layers, MG presented intercellular spaces in palisade layers, and LG displayed deformed palisade cells. Electron photomicrographs of those mesophyll cells demonstrated a gradual breakdown of the chloroplasts. Chlorophyll a/b and carotene were proportionally reduced in the sectors with reduced green pigments, whereas white sectors have hardly any of these pigments. The colour segmentation system based on machine-learning image analysis was able to convert leaf variegation patterns into binary images for quantitative measurements. The bulk segregant analysis of pooled wild-type-like and variegated progeny enabled the identification of SNP and InDels via bioinformatic analysis. The mutation mapping bioinformatic pipeline revealed a region with three candidate genes in chromosome 4, of which the FtsH-like protein precursor (LOC100037730) carries an SNP that we consider the causal variegated phenotype mutation. Phylogenetic analysis shows the candidate is evolutionary closest to the Arabidopsis VAR1. The synonymous mutation created by the SNP generated a miRNA binding site, potentially disrupting the photoprotection mechanism and thylakoid development, resulting in leaf variegation., Conclusion: We described the histology, anatomy, physiology, and image analysis of four classes of cell layers and chloroplast degradation in a tomato plant with a variegated phenotype. The genomics and bioinformatics pipeline revealed a VAR1-related FtsH mutant, the first of its kind in tomato variegation phenotypes. The miRNA binding site of the mutated SNP opens the way to future studies on its epigenetic mechanism underlying the variegation., (© 2024. The Author(s).)

The cysteine-free acyclic peptides present in marine cone snail venom have been much less investigated than their disulfide bonded counterparts. Precursor protein sequences derived from transcriptomic data, together with mass spectrometric fragmentation patterns for peptides present in venom duct tissue extracts, permit the identification of mature peptides. Twelve distinct gene superfamiles have been identified with precursor lengths between 64 and 158 residues. In the case of Conus monile, three distinct mature peptides have been identified, arising from two distinct protein precursors. Mature acyclic peptides are often post-translationally modified, with C-terminus amidation, a feature characteristic of neuropeptides. In the present study, 20 acyclic peptides from Conus monile and Conus betulinus were identified. The common modifications of C-terminus amidation, gamma carboxylation of glutamic acid (E to ϒ), N-terminus conversion of Gln (Q) to a pyroglutamyl residue (Z), and hydroxylation of Pro (P) to Hyp (O) are observed in one or more peptides identified in this study. Proteolytic trimming of sequences by cleavage at the C-terminus of Asn (N) residues is established. The presence of an asparagine endopeptidase is strengthened by the identification of legumain-like sequences in the transcriptome assemblies from diverse Conus species. Such sequences may be expected to have a cleavage specificity at Asn-Xxx peptide bonds., (© 2023 European Peptide Society and John Wiley & Sons, Ltd.)

Prothymosin α (ProT), a highly acidic nuclear protein with multiple cellular functions, has shown potential neuroprotective properties attributed to its anti‑necrotic and anti‑apoptotic activities. The present study aimed to investigate the beneficial effect of ProT on neuroplasticity after ischemia‑reperfusion injury and elucidate its underlying mechanism of action. Primary cortical neurons were either treated with ProT or overexpressing ProT by gene transfection and exposed to oxygen‑glucose deprivation for 2 h in vitro . Immunofluorescence staining for ProT and MAP‑2 was performed to quantify ProT protein expression and assess neuronal arborization. Mice treated with vehicle or ProT (100 µg/kg) and ProT overexpression in transgenic mice received middle cerebral artery occlusion for 50 min to evaluate the effect of ProT on neuroplasticity‑associated protein following ischemia‑reperfusion injury. The results demonstrated that in cultured neurons ProT significantly increased neurite lengths and the number of branches, accompanied by an upregulation mRNA level of brain‑derived neurotrophic factor. Furthermore, ProT administration improved the protein expressions of synaptosomal‑associated protein, 25 kDa and postsynaptic density protein 95 after ischemic‑reperfusion injury in vivo . These findings suggested that ProT can potentially induce neuroplasticity effects following ischemia‑reperfusion injury.

The purpose of this study was to investigate the diagnostic efficacy of contrast-enhanced ultrasound (CEUS) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) combined with tumor markers alpha-fetoprotein (AFP) and des-γ-carboxyl prothrombin (DCP) for primary hepatic carcinoma (PHC). A total of 70 patients with PHC (PHC group), 42 patients with liver cyst (benign liver disease group (BLDG)) and 30 healthy people (healthy group (HG)) were selected as the research objects. CEUS and DCE-MRI were performed by American GE Vivid E9 color Doppler ultrasound system and Siemens 1.5T magnetic resonance imager, respectively. The levels of AFP and DCP were detected by ABBOTT i2000SR chemiluminescence instrument and enzyme-linked immunoassay (ELISA), respectively. In DCE-MRI examination, the portal phase and prolonged phase were mostly low signal in T1-weighted imaging (T1WI) sequence, and arterial phase was mostly high signal in T2WI sequence. In CEUS, most lesions showed hyper-enhancement in arterial phase, and hypo-enhancement in portal phase and delayed phase. AFP and DCP levels in PHC group were significantly higher than that in BLDG group and HG group. There were statistically significant differences among the three groups. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of combined diagnosis were statistically significant when compared with CEUS, AFP and DCP alone and either AFP or DCP positive. CEUS, DCE-MRI combined with tumor markers AFP and DCP have high sensitivity, specificity and accuracy in the diagnosis of PHC, which can more accurately diagnose the lesion type, provide basis for further treatment, and is worthy of clinical application.

Many insulin gene variants alter the protein sequence and result in monogenic diabetes due to insulin insufficiency. However, the molecular mechanisms of various disease-causing mutations are unknown. Insulin is synthesized as preproinsulin containing a signal peptide (SP). SPs of secreted proteins are recognized by the signal recognition particle (SRP) or by another factor in a SRP-independent pathway. If preproinsulin uses SRP-dependent or independent pathways is still debatable. We demonstrate by the use of site-specific photocrosslinking that the SRP subunit, SRP54, interacts with the preproinsulin SP. Moreover, SRP54 depletion leads to the decrease of insulin mRNA and protein expression, supporting the involvement of the RAPP protein quality control in insulin biogenesis. RAPP regulates the quality of secretory proteins through degradation of their mRNA. We tested five disease-causing mutations in the preproinsulin SP on recognition by SRP and on their effects on mRNA and protein levels. We demonstrate that the effects of mutations are associated with their position in the SP and their severity. The data support diverse molecular mechanisms involved in the pathogenesis of these mutations. We show for the first time the involvement of the RAPP protein quality control pathway in insulin biogenesis that is implicated in the development of neonatal diabetes caused by the Leu13Arg mutation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Brain-derived neurotrophic factor (BDNF) and its precursor, proBDNF, are known to significantly contribute to brain homeostasis, neuroplasticity, and neuronal remodeling. Although these neurotrophins are thought to have opposing roles, both play a critical part in shaping long-lasting behavioral changes following substance use. In this context, our study sought to explore the implications of these neurotrophins in the pathophysiology of cocaine use disorder (CUD). We conducted a case-control study, which included 28 individuals seeking treatment for CUD and 38 matched healthy participants. We measured peripheral neurotrophin concentrations via an enzyme-linked immunosorbent assay. Additionally, all participants were screened for cocaine-associated pathways (e.g., cocaine intake, craving intensity), along with associated psychopathological data. Our findings highlighted an increased concentration of BDNF and proBDNF in CUD individuals when compared to healthy controls (BDNF: 18092.80 ± 6844.62 vs. 11334.42 ± 5061.85 pg/ml, p < 0.001; proBDNF: 87.03 ± 33.23 vs. 55.70 ± 23.26 ng/ml, p < 0.001). We further corroborated the relationship between neurotrophin levels and CUD using a linear regression model. Nevertheless, there was no significant difference in the proBDNF to BDNF ratio between the two groups. Interestingly, our study also demonstrated the influence of factors like usage of psychotropic medications, history of psychiatric hospitalizations, and psychiatric diagnoses on neurotrophin dynamics. In conclusion, our study underscores the significance of neurotrophin fluctuations in CUD. The observed increase in BDNF and proBDNF levels could play a pivotal role in driving craving and relapse risk. Thus, a nuanced understanding of these neurobiological underpinnings in CUD might contribute to the development of more targeted and effective therapeutic strategies., (© 2023. The Author(s).)

Exercise promotes brain plasticity partly by stimulating increases in mature brain-derived neurotrophic factor (mBDNF), but the role of the pro-BDNF isoform in the regulation of BDNF metabolism in humans is unknown. We quantified the expression of pro-BDNF and mBDNF in human skeletal muscle and plasma at rest, after acute exercise (+/- lactate infusion), and after fasting. Pro-BDNF and mBDNF were analyzed with immunoblotting, enzyme-linked immunosorbent assay, immunohistochemistry, and quantitative polymerase chain reaction. Pro-BDNF was consistently and clearly detected in skeletal muscle (40-250 pg mg -1 dry muscle), whereas mBDNF was not. All methods showed a 4-fold greater pro-BDNF expression in type I muscle fibers compared to type II fibers. Exercise resulted in elevated plasma levels of mBDNF (55%) and pro-BDNF (20%), as well as muscle levels of pro-BDNF (∼10%, all P  < 0.05). Lactate infusion during exercise induced a significantly greater increase in plasma mBDNF (115%, P  < 0.05) compared to control (saline infusion), with no effect on pro-BDNF levels in plasma or muscle. A 3-day fast resulted in a small increase in plasma pro-BDNF (∼10%, P  < 0.05), with no effect on mBDNF. Pro-BDNF is highly expressed in human skeletal muscle, particularly in type I fibers, and is increased after exercise. While exercising with higher lactate augmented levels of plasma mBDNF, exercise-mediated increases in circulating mBDNF likely derive partly from release and cleavage of pro-BDNF from skeletal muscle, and partly from neural and other tissues. These findings have implications for preclinical and clinical work related to a wide range of neurological disorders such as Alzheimer's, clinical depression, and amyotrophic lateral sclerosis., Competing Interests: None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Physiological Society.)

Holdase chaperones are essential in the mitochondrial membrane-protein biogenesis as they stabilize preproteins and keep them in an import-competent state as they travel through the aqueous cytosol and intermembrane space. The small TIM chaperones of the mitochondrial intermembrane space function within a fine balance of client promiscuity and high affinity binding, while being also able to release their client proteins without significant energy barrier to the downstream insertases/translocases. The tendency of the preproteins to aggregate and the dynamic nature of the preprotein-chaperone complexes makes the preparation of these complexes challenging. Here we present two optimized methods for complex formation of highly hydrophobic precursor proteins and chaperones: a pull-down approach and an in-vitro translation strategy. In the former, attaching the client protein to an affinity resin keeps the individual client protein copies apart from each other and decreases the client self-aggregation probability, thereby favouring complex formation. In the latter approach, a purified chaperone, added to the cell-free protein synthesis, captures the nascent precursor protein. The choice of method will depend on the desired client-chaperone complex amount, or the need for specific labeling scheme., (Copyright © 2024. Published by Elsevier Inc.)

Mitochondria contain about 1000 different proteins, only a handful of which are encoded in the mitochondrial genome. The remaining c. 99% of mitochondrial proteins are encoded in the nuclear genome, synthesized on cytosolic ribosomes as precursor proteins with specific mitochondrial targeting signals and are subsequently imported into the organelle. Mitochondrial targeting signals are very diverse and mitochondria therefore also have a number of very sophisticated molecular machines that recognize, import and sort mitochondrial precursor proteins to the different mitochondrial subcompartments. The ability to synthesize mitochondrial precursor proteins in vitro and subsequently import them into isolated mitochondria has revolutionized our understanding of mitochondrial protein import pathways. Here, we describe the basic protocol for synthesis of mitochondrial precursor proteins in vitro and their subsequent import into isolated mitochondria from yeast Saccharomyces cerevisiae, the method which was used to elucidate and characterize the vast majority of mitochondrial protein import pathways., (Copyright © 2024. Published by Elsevier Inc.)

The vast majority of mitochondrial precursor proteins is synthesized in the cytosol and subsequently imported into the organelle with the help of targeting signals that are present within these proteins. Disruptions in mitochondrial import will result in the accumulation of the organellar precursors in the cytosol of the cell. If mislocalized proteins exceed their critical concentrations, they become prone to aggregation. Under certain circumstances, protein aggregation becomes an irreversible process, which eventually endangers cellular health. Impairment in mitochondrial biogenesis and its effect on cellular protein homeostasis were recently linked to neurodegeneration, therefore placing this process in the center of attention. In this chapter, we are presenting a set of techniques that allows to monitor and study mitochondrial precursor protein aggregates upon mitochondrial dysfunction in the cytosol of both yeast and human cells., (Copyright © 2024. Published by Elsevier Inc.)

The maturation of mitochondrial presequence precursor proteins after their import into the organelle is a complex process that requires the interaction of several mitochondrial proteases. Precursor processing by the mitochondrial presequence proteases is directly coupled to the proteolytic turnover of the cleaved targeting signal by mitochondrial presequence peptidases. Dysfunction of these enzymes is associated with a variety of human diseases, including neurological disorders, cardiomyopathies and renal diseases. In this chapter, we describe experimental approaches to study the activity of the major mitochondrial presequence protease (MPP) and of the presequence peptidases. In vitro assays and soluble mitochondrial extracts allow the assessment and experimental manipulation of peptidase and protease activity using immunoblotting, fluorescence measurements and autoradiography as readouts. In particular, the assays allow manipulation at multiple levels including in vivo, in organello or in soluble extracts/in vitro. Purification of the yeast heterodimeric MPP allows in vitro reconstitution of the initial presequence processing step using radiolabeled precursors as substrates. Application of soluble mitochondrial extracts enables direct assessment of MPP processing and presequence peptide turnover which can be easily manipulated and is uncoupled from protein translocation across the mitochondrial membranes. The techniques presented in this chapter allow in-depth analysis of precursor processing and presequence turnover as well as direct assessment of the impact of patient mutations on the activity of the presequence processing machinery., (Copyright © 2024. Published by Elsevier Inc.)