👤 Marcin Krawczyk

Neurological disorders cause over 11 million deaths annually worldwide, highlighting the urgent need for new therapeutic strategies to improve current treatment outcomes. Nerve growth factor (NGF) is a key regulator of neuronal survival, and modifying mesenchymal stem cells (MSC) to enhance their neurotrophic activity is a promising therapeutic strategy. However, the broader molecular consequences of NGF overexpression in MSC remain unclear. This study examined how NGF overexpression affects neurotrophin secretion and apoptosis-related protein expression in Wharton's jelly MSC (WJ-MSC). WJ-MSC were lentivirally transduced to overexpress NGF and differentiated for 12 days. NGF, BDNF, TrkA, TrkB, IL-13, and TNF-α were quantified using ELISA (n = 3 biological replicates; assays in duplicate). Thirty-five apoptosis-related proteins were assessed using the Proteome Profiler Human Apoptosis Array (assays in duplicate). Data were analyzed using one-way ANOVA or multiple t-test. NGF overexpression increased extracellular NGF (↑∼220 %, p < 0.0001) and reduced BDNF secretion (↓∼35 %, p < 0.05). Soluble phosphorylated TrkA/TrkB increased significantly in supernatants (↑30-60 %, p < 0.05). IL-13 rose modestly without statistical significance, and TNF-α remained undetectable. Early proteome changes showed upregulation of pro-apoptotic proteins (p21 ↑97 %, phospho-p53 ↑30 %) with concurrent reductions in anti-apoptotic markers (BCL2 ↓66 %, HSP60 ↓58 %). After 12 days, the apoptotic profile remained predominantly pro-apoptotic, despite selective increases in BCLXL (↑92 %), clusterin (↑102 %), and survivin (↑38 %) indicating only partial compensatory responses. NGF overexpression enhances neurotrophin-related signaling but produces a sustained pro-apoptotic shift in WJ-MSC, suggesting limited benefit for cell survival. These findings require confirmation using functional apoptosis assays and in vivo models. Show less

Histatins are multifunctional histidine-rich peptides secreted by the salivary glands and exclusively present in the saliva of higher primates, where they play a fundamental role in the protection of the oral cavity. Our previously published results demonstrated that histatin-1 (Hst1) promotes cell-substrate adhesion in various cell types and hinted that it could also be involved in cell-cell adhesion, a process of fundamental importance to epithelial and endothelial barriers. Here we explore the effects of Hst1 on cellular barrier function. We show that Hst1 improved endothelial barrier integrity, decreased its permeability for large molecules, and prevented translocation of bacteria across epithelial cell layers. These effects are mediated by the adherens junction protein E-cadherin (E-cad) and by the tight junction protein zonula occludens 1, as Hst1 increases the levels of zonula occludens 1 and of active E-cad. Hst1 may also promote epithelial differentiation as Hst1 induced transcription of the epithelial cell differentiation marker apolipoprotein A-IV (a downstream E-cad target). In addition, Hst1 counteracted the effects of epithelial-mesenchymal transition inducers on the outgrowth of oral cancer cell spheroids, suggesting that Hst1 affects processes that are implicated in cancer progression.-Van Dijk, I. A., Ferrando, M. L., van der Wijk, A.-E., Hoebe, R. A., Nazmi, K., de Jonge, W. J., Krawczyk, P. M., Bolscher, J. G. M., Veerman, E. C. I., Stap, J. Human salivary peptide histatin-1 stimulates epithelial and endothelial cell adhesion and barrier function. Show less

Obese, insulin-resistant states are characterized by a paradoxical pathogenic condition in which the liver appears to be selectively insulin resistant. Specifically, insulin fails to suppress glucose production, yet successfully stimulates de novo lipogenesis. The mechanisms underlying this dysregulation remain controversial. Here, we hypothesized that carbohydrate-responsive element-binding protein (ChREBP), a transcriptional activator of glycolytic and lipogenic genes, plays a central role in this paradox. Administration of fructose increased hepatic hexose-phosphate levels, activated ChREBP, and caused glucose intolerance, hyperinsulinemia, hypertriglyceridemia, and hepatic steatosis in mice. Activation of ChREBP was required for the increased expression of glycolytic and lipogenic genes as well as glucose-6-phosphatase (G6pc) that was associated with the effects of fructose administration. We found that fructose-induced G6PC activity is a major determinant of hepatic glucose production and reduces hepatic glucose-6-phosphate levels to complete a homeostatic loop. Moreover, fructose activated ChREBP and induced G6pc in the absence of Foxo1a, indicating that carbohydrate-induced activation of ChREBP and G6PC dominates over the suppressive effects of insulin to enhance glucose production. This ChREBP/G6PC signaling axis is conserved in humans. Together, these findings support a carbohydrate-mediated, ChREBP-driven mechanism that contributes to hepatic insulin resistance. Show less

Non-alcoholic fatty liver disease (NAFLD), the most common liver disorder in the Western world, is a clinico-histopathological entity in which excessive triglyceride accumulation in the liver occurs. Non-alcoholic steatohepatitis (NASH) represents the necroinflammatory form, which can lead to advanced liver fibrosis, cirrhosis, and hepatocellular carcinoma. The pathogenesis of NAFLD/NASH is complex but increased visceral adiposity plus insulin resistance with increased free fatty acids release play an initial key role for the onset and perpetuation of liver steatosis. Further events in the liver include oxidative stress and lipid peroxidation, decreased antioxidant defences, early mitochondrial dysfunction, iron accumulation, unbalance of adipose-derived adipokines with a chronic proinflammatory status, and gut-derived microbial adducts. New gene polymorphisms increasing the risk of fatty liver, namely APOC3 and PNPLA3, have been lately identified allowing further insights into the pathogenesis of this condition. In our review pathophysiological, genetic, and essential diagnostic and therapeutic aspects of NAFLD are examined with future trends in this field highlighted. Show less