Biochemistry and Cell Biology最新文献

Diabetic nephropathy (DN) is one of the most common complications of diabetes. Our previous study showed that CD38 knockout (CD38KO) mice had protective effects on many diseases. However, the roles and mechanisms of CD38 in DN remain unknown. Here, DN mice were generated by high-fat diet (HFD) feeding plus streptozotocin (STZ) injection in male CD38KO and CD38flox mice. Mesangial cells (SV40 MES 13 cells) were used to mimic the injury of DN with palPagination Donemitic acid (PA) treatment in vitro. Our results showed that CD38 expression was significantly increased in kidney of diabetic CD38flox mice and SV40 MES 13 cells treated with PA. CD38KO mice were significantly resistant to diabetes-induced renal injury. Moreover, CD38 deficiency markedly decreased HFD/STZ-induced lipid accumulation, fibrosis, and oxidative stress in kidney tissue. In contrast, overexpression of CD38 aggravated PA-induced lipid accumulation and oxidative stress. CD38 deficiency increased expression of SIRT3, while overexpression of CD38 decreased its expression. More importantly, 3-TYP, an inhibitor of SIRT3, significantly enhanced PA-induced lipid accumulation and oxidative stress in CD38 overexpressing cell lines. In conclusion, our results demonstrated that CD38 deficiency prevented DN by inhibiting lipid accumulation and oxidative stress through activation of the SIRT3 pathway.

Enucleated cells, also known as cytoplasts, are valuable tools with a wide range of applications. However, their potential for bio-engineering is greatly restricted by the short lifespan. We postulated that the enucleation process damages the integrity of the plasma membrane and thus activates a cell death program(s). The results showed that a tiny hole was generated transiently on the plasma membrane when the nucleus was spun off, while force-gated ion channels were activated in response to the pulling by the nucleus. Influx of extracellular calcium stimulated the opening of calcium channels and the release of calcium from endoplasmic reticulum and mitochondria. Long lasting calcium transient increased protein phosphorylation and activated caspase 9 and calpain proteinase activities. Subsequently, mitochondria membrane permeability and Reactive Oxygen Species (ROS) levels were significantly elevated, which eventually led to eryptosis-like cell death. When extracellular calcium was maintained at optimal concentration, the lifespan of enucleated cells was extended; however, huge amounts of vacuoles appeared in the cytoplasm, possibly derived from enlarged autophagosomes. Inhibition of vacuolation by inhibitors of autophagy or in co-culture with primary muscle cells did not rescue cells dying from the paraptosis-like pathway. These results offer valuable insights for further investigation into the intricate mechanisms underlying enucleated cell death.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of diarrhea in humans and animals. The study aimed to evaluate the efficacy of bovine lactoferrin (bLf) as an adjuvant combined with AMP (N6) in the treatment of E. coli-induced bacterial enteritis. Firstly, 40 female ICR mice were randomly divided into four groups. The ETEC-A, ETEC-B, and ETEC-C groups were gavaged with 0.2 mL of ETEC K88 at 5 × 10⁹, 5 × 10⁸, and 5 × 10⁷ CFU/mL for three consecutive days, respectively, the CK control group was given PBS. Based on the clinical symptoms and intestinal changes, the optimal model dose of ETEC K88 was determined to be 5 × 10⁸ CFU/mL. Sixty female ICR mice were randomly divided into six groups: CK group (uninfected), NC group (infected and untreated), N6 treatment group (20 mg/kg), bLf treatment group (100 mg/kg), bLf + N6-A treatment group (10 mg/kg N6+100 mg/kg bLf), and bLf + N6-B group (20 mg/kg N6+100 mg/kg bLf). The clinical symptoms, intestinal morphology, inflammatory response and serum metabolites were monitored. The results showed that compared with the NC group, the bLf-N6-A and bLf-N6-B treatment groups had significant reductions in TNF-α and IL-6, significant increases in IL-10, and significant reductions in endotoxin and DAO in plasma (p < 0.05). Meanwhile, the bLf-N6-A and bLf-N6-B treatment groups significantly increased the expression of ZO-1, claudin-1 and occludin, increased the height of small intestinal mucosal villi and VH/CD after ETEC K88-induced intestinal injury (p < 0.05). The combination of bLf and N6 relieved enteritis by balancing intestinal mucosal immunity, improving intestinal morphology and barrier function. BLf combined with N6 can be used as an effective therapeutic strategy for the treatment of bacterial enteritis.

Myocardial dysfunction is a major cause of early mortality after successful cardiopulmonary resuscitation (CPR) following cardiac arrest (CA). Following the return of spontaneous circulation, myocardial ischemia-reperfusion injury can activate the NF-κB pathway, leading to the transcription of inflammatory genes that impair myocardial function. While clinical studies show hydrocortisone (HC) improves outcomes in CA patients during CPR, its specific role in modulating the NF-κB pathway is unclear. In this study, we established an in vitro model by inducing hypoxia/reoxygenation (H/R) injury in H9C2 cardiomyocytes using Na₂S₂O₄, followed by HC treatment. The results showed that HC treatment of H/R-injured cardiomyocytes promoted proliferation, inhibited apoptosis, and suppressed the NF-κB pathway, thereby reducing interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-α) levels. Moreover, inhibition of the NF-κB pathway enhanced the proliferative capacity of H/R cardiomyocytes, decreased apoptosis rates, and reduced IL-6, IL-8, and TNF-α expression levels, with these effects being further amplified by HC treatment. These findings were further supported by in vivo experiments. In conclusion, our study suggests that HC may promote H/R cardiomyocyte proliferation, inhibit apoptosis, and alleviate inflammatory responses by suppressing the NF-κB pathway, providing new evidence to support its potential clinical application in CA management.

Epicardial adipose tissue (EAT) is a rich source of EAT-derived stromal cells (EATDS), which possess regenerative potential. CRSP2, HSP27, IL8, HSP90, and Cofilin 1 were detected in the secretome of left ventricular stromal cells under ischemia challenge. However, the association of these genes in the EAT and EATDS remain understudied. We aim to assess the status of cofilin 1, CRSP2, HSP27, IL8, and HSP90 in the EAT of myocardial infarction (MI) and coronary artery bypass graft (CABG) swine models and in vitro stimulated ischemic EATDS. Expression status of these proteins in EAT were assessed by immunostaining, and in EATDS using qRT-PCR, immunostaining, and Western blot. EATDS phenotyping was performed using sc-RNAseq analysis. Cofilin 1 was increased while the other four genes were decreased in the CABG. IL8 and HSP90 were increased, while CRSP2, HSP27, and cofilin 1 were decreased in the MI group. Similar trend was displayed in the expression of these genes in EATDS. Additionally, EATDS displayed versatile phenotypes at single cell resolution based on the differential expression of various gene signatures. The findings revealed novel insights into EAT/EATDS biology and further understanding regarding the EATDS sub-phenotypes would open novel avenues in translational cardiology.

Myelination is essential for the proper conduction of impulses across neuronal networks. Mature, myelinating glia differentiate from progenitor cells through distinct stages that correspond to oligodendrocyte-specific gene expression markers. Reverse transcription quantiatative PCR (RT-qPCR) is a common technique used to quantify gene expression across cell development; however, a lack of standardization and transparency in methodology may lead to irreproducible data. Here, we have designed and validated RT-qPCR assays for oligodendrocyte genes and reference genes in the developing C57BL6/J mouse brain that align with the MIQE guidelines, including quality controls for primer specificity, temperature dependence, and efficiency. A panel of eight commonly used reference genes was ranked using a series of reference gene stability methods that consistently identified Gapdh, Sdha, Hmbs, Hprt1, and Pgk1 as the top candidates for normalization across brain regions. In the cerebrum, myelin genes peaked in expression at postnatal day 21, which corresponds to the peak of developmental myelination. The gene expression patterns from the brain homogenate were in agreement with previously reported RNA-seq and microarray profiles from oligodendrocyte lineage cells. The validated RT-qPCR assays begin to build a framework for future investigation into the molecular mechanisms that regulate myelination in mouse models of brain development, aging, and disease.

The field of RNA research has provided profound insights into the basic mechanisms modulating the function and adaption of biological systems. RNA has also been at the center stage in the development of transformative biotechnological and medical applications, perhaps most notably was the advent of mRNA vaccines that were critical in helping humanity through the Covid-19 pandemic. Unbeknownst to many, Canada boasts a diverse community of RNA scientists, spanning multiple disciplines and locations, whose cutting-edge research has established a rich track record of contributions across various aspects of RNA science over many decades. Through this position paper, we seek to highlight key contributions made by Canadian investigators to the RNA field, via both thematic and historical viewpoints. We also discuss initiatives underway to organize and enhance the impact of the Canadian RNA research community, particularly focusing on the creation of the not-for-profit organization RNA Canada ARN. Considering the strategic importance of RNA research in biology and medicine, and its considerable potential to help address major challenges facing humanity, sustained support of this sector will be critical to help Canadian scientists play key roles in the ongoing RNA revolution and the many benefits this could bring about to Canada.

Over the past four decades, prion diseases have received considerable research attention owing to their potential to be transmitted within and across species as well as their consequences for human and animal health. The unprecedented nature of prions has led to the discovery of a paradigm of templated protein misfolding that underlies a diverse range of both disease-related and normal biological processes. Indeed, the "prion-like" misfolding and propagation of protein aggregates is now recognized as a common underlying disease mechanism in human neurodegenerative disorders such as Alzheimer's and Parkinson's disease, and the prion principle has led to the development of novel diagnostic and therapeutic strategies for these illnesses. Despite these advances, research into the fundamental biology of prion diseases has declined, likely due to their rarity and the absence of an acute human health crisis. Given the past translational influence, continued research on the etiology, pathogenesis, and transmission of prion disease should remain a priority. In this review, we highlight several important "unsolved mysteries" in the prion disease research field and how solving them may be crucial for the development of effective therapeutics, preventing future outbreaks of prion disease, and understanding the pathobiology of more common human neurodegenerative disorders.

Atherosclerosis (AS) is an inflammatory arterial disorder that occurs due to the deposition of the excessive lipoprotein under the artery intima, mainly including low-density lipoprotein and other apolipoprotein B-containing lipoproteins. G protein-coupled receptors (GPCRs) play a crucial role in transmitting signals in physiological and pathophysiological conditions. GPCRs recognize inflammatory mediators, thereby serving as important players during chronic inflammatory processes. It has been demonstrated that free fatty acids can function as ligands for various GPCRs, such as free fatty acid receptor (FFAR)1/GPR40, FFAR2/GPR43, FFAR3/GPR41, FFAR4/GPR120, and the lipid metabolite binding glucose-dependent insulinotropic receptor (GPR119). This review discusses GPR43 and its ligands in the pathogenesis of AS, especially focusing on its distinct role in regulating chronic vascular inflammation, inhibiting oxidative stress, ameliorating endothelial dysfunction and improving dyslipidemia. It is hoped that this review may provide guidance for further studies aimed at GPR43 as a promising target for drug development in the prevention and therapy of AS.