Biological Research最新文献

Background: Aging affects the reparative potency of mesenchymal stem/stromal cells (MSCs) by diminishing their proliferation and differentiation capability; making them unsuitable for regenerative purposes. Earlier we showed that MSCs acquire the expression of CD45 as a consequence of aging, and this increased expression is associated with downregulated expression of osteogenic markers and upregulated expression of adipogenic and osteoclastogenic markers. However, whether CD45 is actively involved in the aging-mediated deregulated differentiation in the MSCs was not elucidated.

Results: In the present study, we showed that pharmacological inhibition of CD45-specific phosphatase activity in the aged MSCs restores their differentiation potential to young-like. Investigation of the molecular mechanism involved in the process showed that several regulatory kinases like p38, p44/42, Src, and GSK3β are in their dephosphorylated form in the aged MSCs, and importantly, this status gets reversed by the application of a CD45-specific PTP inhibitor. Conversely, pharmacological inhibition of these kinases in young MSCs imposes an aged-like gene expression profile on them. Additionally, we also showed that the secretome of aged MSCs affects the viability and differentiation of primary chondrocytes, and this detrimental effect is reversed by treating aged MSCs with the PTP inhibitor. Our data demonstrate that the aging-mediated expression of CD45 in MSCs alters their differentiation profile by dephosphorylating several kinases and treating the aged MSCs with a CD45 PTP activity inhibitor rejuvenates them.

Conclusions: CD45 can be used as an aging marker for mesenchymal stem cells. Alteration of CD45 phosphatase activity could have significant implications for the use of MSCs in regenerative medicine.

Objective: We aimed to explore the heterogeneities and communication properties of cardiac CMs and ECs in diabetes.

Methods: GSE213337 dataset was retrieved from NCBI Gene Expression Omnibus, containing the single-cell RNA sequencing data of hearts from the control and streptozotocin-induced diabetic mice. Cell cluster analysis was performed to identify the cell atlas. Data of CMs and ECs were extracted individually for re-cluster analysis, functional enrichment analysis and trajectory analysis. Cell communication analysis was conducted to explore the altered signals and significant ligand-receptor interactions.

Results: Eleven cell types were identified in the heart tissue. CMs were re-clustered into four subclusters, and cluster 4 was dominant in diabetic condition and enriched in cellular energy metabolism processes. ECs were re-clustered into six subclusters, and clusters 2, 4 and 5 were dominant in the diabetic condition and mainly enriched in cellular energy metabolism and lipid transport processes. The cellular communication network was altered in the diabetic heart. ECs dominated the overall signaling and notably increased the ANGPTL and SEMA4 signals in the diabetic heart. Four significant ligand-receptor pairs implicating the two signals contributed to the communication between ECs and other cell types, including Angptl1-(Itga1 + Itgb1), Angptl4-Cdh5, Angptl4-Sdc3, and Sema4a-(Nrp + Plxna2). The ligand Angptl4 engaged in ECs-CMs communication in a paracrine manner.

Conclusion: Single-cell sequencing analysis revealed heterogeneities of ECs and CMs in diabetes, Angptl4-Cdh5 and Angptl4-Sdc3 were involved in the communication between ECs and CMs in diabetes.

Fragile X Syndrome (FXS) is the most common monogenetic cause of autism and inherited intellectual disability. A key feature of FXS symptomatology is altered sensory processing greatly affecting FXS individual's life quality. Here, we use a combination of behavioral tests and slice physiology tools to study the neurophysiological alterations underlying aberrant sensory processing in the olfactory system of the FXS mouse model (Fmr1 KO). We focused on the piriform cortex (PC), since it is in this brain region where olfactory information is integrated and ultimately decoded. Using a go-no go behavioral task we have found that Fmr1 KO learn to discriminate between a rewarded and a not rewarded odorant but cannot distinguish complex odor mixtures, akin to what is found in the environment. Moreover, Fmr1 KO long-term memory is impaired compared to control mice suggesting possibly cortical processing alterations. In addition, electrophysiological data from PC layer II neurons of Fmr1 KO mice showed a hyperexcitable phenotype manifested by differences in active membrane properties and altered network connectivity. Taken together, our data suggest a possible causal link between the observed olfactory discrimination deficiencies in the Fmr1 KO mouse and the altered physiology of PC.

Background: Stem cell therapies may potentially be used in regenerative and reconstructive medicine due to their ability for self-renewal and differentiation. Stressful conditions, such as hyperglycemia, adversely affect stem cell functions, impairing their function and promoting differentiation by opposing self-renewal. The carboxyl terminus of HSP70 interacting protein (CHIP), which is a cochaperone and E3 ligase, maintains protein homeostasis and performs quality control of the cell via ubiquitylation. However, the role of CHIP in regulating stemness remains unknown.

Results: Hyperglycemia downregulated CHIP-induced p53, arrested the cell cycle at the gap (G₁) phase, and promoted the loss of stemness in WJMSCs. Quantitative real-time polymerase chain reaction (qRT-PCR), Western blotting, immunofluorescence, and cell cycle analysis showed that CHIP-overexpressing WJMSCs downregulated the expression of phosphorylated p53 and shortened its half-life while enhancing self-renewal factors. Additionally, co-IP and Western blotting revealed that CHIP promoted the ubiquitination and proteasomal degradation of hyperglycemia-induced p53 through the chaperone system.

Conclusions: CHIP may promote ubiquitin-mediated proteasomal degradation of hyperglycemia-induced p53 rescues self-renewal genes, which can maintain the long-term undifferentiated state of WJMSCs. CHIP may be an alternative therapeutic option in regenerative medicine for hyperglycemic-related complications in diabetes.

Alzheimer's disease (AD) is a neurodegenerative disorder influenced by both genetic and environmental factors. Identifying therapeutic targets and interventions remains challenging. This study utilized Mendelian Randomization (MR) to investigate causal relationships between plasma proteins, lifestyle factors, and AD, along with virtual screening to identify potential drug compounds. A two-sample MR analysis assessed associations between plasma proteins, identified through genome-wide association studies (GWAS), and AD risk. Co-localization analysis (CA) confirmed the overlap between protein expression and AD susceptibility loci, and reverse MR ruled out reverse causality. A protein-protein interaction (PPI) network was constructed to explore therapeutic targets, followed by virtual screening to identify small-molecule inhibitors for selected proteins. The analysis found significant associations between eight plasma proteins and AD, with five proteins (GSTP1, BIN1, Siglec-3, SERPINF2, and GRN) showing strong evidence of involvement in AD pathogenesis. Virtual screening identified six compounds as potential inhibitors of GSTP1 and four compounds as potential inhibitors of BIN1. Furthermore, MR analysis of lifestyle factors, such as dietary behaviors and smoking cessation, indicated they may influence AD risk through their effects on specific proteins. These findings offer novel insights into the genetic mechanisms underlying AD and highlight the potential of combining MR with virtual screening to identify therapeutic targets. The study also suggests that lifestyle modifications could offer alternative prevention and treatment strategies for AD. Future research should focus on the experimental validation of the identified compounds and further explore the mechanisms linking lifestyle factors to AD.

Background: Spinocerebellar ataxia 19/22 (SCA19/22) represents a rare autosomal dominant genetic disorder resulting in progressive ataxia and cerebellar atrophy. SCA19/22 is caused by variants in the KCND3 gene, which encodes a voltage-gated potassium channel subunit essential for cerebellar Purkinje cell function. To date, 22 variants have been reported worldwide, with incomplete functional studies.

Results: We present four Chilean and Mexican cases in whom two single-nucleotide variants were identified through whole-exome sequencing of the probands. One variant (G371R) was initially cataloged as pathogenic and the other (S357W) as likely pathogenic according to the American College of Medical Genetics and Genomics criteria. The pathogenicity of the G371R variation was confirmed by in-silico mutagenesis. Our molecular models, that include electrostatic potential analysis and algorithms to analyze the pore dimensions (HOLE), indicated that the longer side chain of the arginine narrowed the channel's selectivity filter, while the positive charge modified its surface electrostatic potential, presumably preventing potassium flux. Functional characterization of the S357W variant was performed in AD293 cells. When overexpressed, K_V4.3^S357W channels alone showed no current. Protein electrophoresis revealed that the total number of K_V4.3 channels expressed did not differ between the wild-type and mutated phenotypes, suggesting a protein trafficking malfunction. Co-expression of the KChIP2 auxiliary subunit partially rescued the potassium currents when the variant was expressed, albeit with very different biophysical characteristics, including faster inactivation vs. wild-type channels.

Conclusions: This functional characterization of two KCND3 variants associated with SCA19/22 adds new evidence for the pathogenic role of Kv4.3 loss-of-function mutations and establishes a correlation between functional dominance and clinical severity in SCA19/22.

Background: Varicose veins (VV) are spectrum of common vascular diseases having complex genetic etiology. The Castor Zinc Finger 1 (CASZ1) gene has been involved in vascular development and its variant has shown association with VV in various ethnicities, but CASZ1 susceptibility to VV risk is unexplored in the South Asian Indian population. The objective of this study was to estimate the association of the CASZ1 gene variations and VV susceptibility in the South Asian Indians, and to examine the evolutionary patterns of these variants compared to other populations.

Methodology: Population based case control analysis was conducted on all CASZ1 variants present in the Global Screening Array, including the established VV variant rs11121615 with a focus on validating and identification of both novel and established genetic markers to capture a full spectrum of population-specific genetic markers unique to studied population group. Linkage disequilibrium patterns and cumulative variant effects were also analyzed, followed by selection pressure assessment using neutrality tests.

Results: Three CASZ1 variants rs72860191 (OR 1.58, 95% CI 1.07-2.32, p = 0.01), rs7519604 (OR 1.43, 95% CI 1.05-1.94, p = 0.01), and rs11121615 (OR 0.69, 95% CI 0.50-0.95, p = 0.02) were observed to be significantly associated with VV. Haplotype analysis identified unique haplotype structure of South Asian Indians compared to other global populations. Moreover, the cumulative OR was observed to be higher than the independently estimated values (OR = 2.41, 95% CI 1.48-3.94), indicating genotypic epistasis of VV associated variants. The neutrality tests revealed balancing selection within CASZ1 in the studied population compared to other populations, CONCLUSION: The present study identified CASZ1 variants and their epistatic interactions is associated with VV susceptibility supported with evidence of balancing selection, provides crucial insights into the genetic architecture of VV in studied group, highlighting the impact of evolutionary forces on disease susceptibility.

Background: Pancreatic cancer is among the most aggressive and malignant tumors and is a leading cause of cancer-related mortality. It is characterized by its metabolic Warburg effect and glucose dependence. Aerobic glycolysis is a key feature of metabolic reprogramming in cancer cells. This study investigates the combined effect of metformin and FX11, hypothesizing that disrupting cancer cell energetics through complementary mechanisms may result in a synergistic therapeutic effect. The combination of metformin and FX11 affects the axis that regulates vital functions in cancer cells; thus, the uncontrolled growth of tumor cells, especially those that use a lactose-dependent energy pathway, can be controlled. Several in vitro experiments were conducted to evaluate this hypothesis. PANC-1 cell proliferation was assessed using an MTS assay, lactate levels were measured via an LDH assay, and apoptosis was determined using a flow cytometry-based PE-annexin V assay. The downstream effects of metformin and FX11 treatment were evaluated via western blot analysis.

Results: The findings of this study revealed that metformin and FX11 significantly decreased the viability of PANC-1 cells when used in combination, and this effect was achieved by significantly affecting the energy mechanism of the cells through the AMPKα axis. Furthermore, the lactate levels in PANC1 cells co-treated with metformin and FX11 were significantly decreased, while the increased cellular stress led the cells to apoptosis.

Conclusions: Compared with metformin treatment alone, the combination treatment of metformin and FX11 stimulates cellular stress in pancreatic cancer and targets various energy processes that encourage cancer cells to undergo apoptosis. This study provides a novel therapeutic strategy for the treatment of pancreatic cancer.

In the progression of gastric cancer (GC), various cell types in the tumor microenvironment (TME) exhibit upregulated expression of programmed death ligand 1 (PD-L1), leading to impaired T-cell function and evasion of immune surveillance. Infection with H. pylori and EBV leads to increased PD-L1 expression in various cell types within TME, resulting in immune suppression and facilitating immune escape of GC cells. In the TME, mesenchymal stem cells (MSCs), M1-like tumor-associated macrophages (MI-like TAM), and myeloid-derived suppressor cells (MDSCs) contribute to the upregulation of PD-L1 expression in GC cells. Conversely, mast cells, M2-like tumor-associated macrophages (M2-like TAM), and tumor-associated neutrophils (TANs) exhibit elevated levels of PD-L1 expression in response to the influence of GC cells. Together, these factors collectively contribute to the upregulation of PD-L1 expression in GC. This review aims to provide a comprehensive summary of the cellular expression patterns of PD-L1 in GC and the underlying molecular mechanisms. Understanding the complex regulatory pathways governing PD-L1 expression may offer novel insights for the development of effective immunotherapeutic interventions.