Integrated analysis of m6A regulator-mediated RNA methylation modification patterns and immune characteristics in Sjögren's syndrome.

The epigenetic modifier N6-methyladenosine (m6A), recognized as the most prevalent internal modification in messenger RNA (mRNA), has recently emerged as a pivotal player in immune regulation. Its dysregulation has been implicated in the pathogenesis of various autoimmune conditions. However, the implications of m6A modification within the immune microenvironment of Sjögren's syndrome (SS), a chronic autoimmune disorder characterized by exocrine gland dysfunction, remain unexplored. Herein, we leverage an integrative analysis combining public database resources and novel sequencing data to investigate the expression profiles of m6A regulatory genes in SS. Our cohort comprised 220 patients diagnosed with SS and 62 healthy individuals, enabling a comprehensive evaluation of peripheral blood at the transcriptomic level. We report a significant association between SS and altered expression of key m6A regulators, with these changes closely tied to the activation of CD4+ T cells. Employing a random forest (RF) algorithm, we identified crucial genes contributing to the disease phenotype, which facilitated the development of a robust diagnostic model via multivariate logistic regression analysis. Further, unsupervised clustering revealed two distinct m6A modification patterns, which were significantly associated with variations in immunocyte infiltration, immune response activity, and biological function enrichment in SS. Subsequently, we proceeded with a screening process aimed at identifying genes that were differentially expressed (DEGs) between the two groups distinguished by m6A modification. Leveraging these DEGs, we employed weight gene co-expression network analysis (WGCNA) to uncover sets of genes that exhibited strong co-variance and hub genes that were closely linked to m6A modification. Through rigorous analysis, we identified three critical m6A regulators - METTL3, ALKBH5, and YTHDF1 - alongside two m6A-related hub genes, COMMD8 and SRP9. These elements collectively underscore a complex but discernible pattern of m6A modification that appears to be integrally linked with SS's pathogenesis. Our findings not only illuminate the significant correlation between m6A modification and the immune microenvironment in SS but also lay the groundwork for a deeper understanding of m6A regulatory mechanisms. More importantly, the identification of these key regulators and hub genes opens new avenues for the diagnosis and treatment of SS, presenting potential targets for therapeutic intervention.

Gut microbiota is associated with spatial memory and seed-hoarding behavior of South China field mice (Apodemus draco).

Background: Scatter-hoarding animals store food in multiple locations within their home range and rely on spatial memory for subsequent localization and retrieval. The relationship between memory and scatter-hoarding behavior has been widely demonstrated, but the association of gut microbiota with spatial memory and seed-hoarding behavior of animals remains unclear. Methods: In this study, by using enclosure behavior tests, memory tests including an object location test (OLT) and a novel object recognition test (NORT), and fecal microbiota transplantation (FMT) experiment, we evaluated the role of gut microbiota in affecting the memory and seed-hoarding behavior of rodents. According to their scatter-hoarding intensity, South China field mice (Apodemus draco) were divided into scatter-hoarding group (SG) and non-scatter-hoarding group (NG). Results: We found that the SG performed better than the NG in the NORT. FMT from SG donor mice altered the NG recipient mice's gut microbiota structure. Further tests demonstrated FMT from SG donor mice increased memory of NG recipient mice in laboratory tests and seed larder hoarding intensity of NG recipient mice in enclosures. Conclusion: Our results suggest gut microbiota could modulate the memory and seed-hoarding behavior of animals.

HECT, UBA and WWE domain containing 1 represses cholesterol efflux during CD4+ T cell activation in Sjögren's syndrome.

Introduction: Sjögren's syndrome (SS) is a chronic autoimmune disorder characterized by exocrine gland dysfunction, leading to loss of salivary function. Histological analysis of salivary glands from SS patients reveals a high infiltration of immune cells, particularly activated CD4+ T cells. Thus, interventions targeting abnormal activation of CD4+ T cells may provide promising therapeutic strategies for SS. Here, we demonstrate that Hect, uba, and wwe domain containing 1 (HUWE1), a member of the eukaryotic Hect E3 ubiquitin ligase family, plays a critical role in CD4+ T-cell activation and SS pathophysiology. Methods: In the context of HUWE1 inhibition, we investigated the impact of the HUWE1 inhibitor BI8626 and sh-Huwe1 on CD4+ T cells in mice, focusing on the assessment of activation levels, proliferation capacity, and cholesterol abundance. Furthermore, we examined the therapeutic potential of BI8626 in NOD/ShiLtj mice and evaluated its efficacy as a treatment strategy. Results: Inhibition of HUWE1 reduces ABCA1 ubiquitination and promotes cholesterol efflux, decreasing intracellular cholesterol and reducing the expression of phosphorylated ZAP-70, CD25, and other activation markers, culminating in the suppressed proliferation of CD4+ T cells. Moreover, pharmacological inhibition of HUWE1 significantly reduces CD4+ T-cell infiltration in the submandibular glands and improves salivary flow rate in NOD/ShiLtj mice. Conclusion: These findings suggest that HUWE1 may regulate CD4+ T-cell activation and SS development by modulating ABCA1-mediated cholesterol efflux and presents a promising target for SS treatment.

Toxicity of o-phenylphenol on craniofacial cartilage development through ROS-induced oxidative stress in zebrafish embryos.

O-phenylphenol (OPP), a commonly used antiseptic and bactericide, has some threat to human health and the environment. Environmental exposure to OPP may cause potential health hazards in animals and humans, and the developmental toxicity of OPP needs to be assessed. Therefore, the zebrafish model was used to evaluate the ecological impact of OPP, and the zebrafish craniofacial skeleton is mainly derived from the cranial neural crest stem cells (NCCs). In this study, zebrafish were exposed to 1,2,4 mg/L OPP from10 to 80 h post-fertilization (hpf). Our study observed that OPP could cause the early disorder of craniofacial pharyngeal arch development and lead to behavioural abnormalities. In addition, qPCR and enzyme activity revealed that OPP exposure would induce the production of reactive oxygen species (ROS) and oxidative stress. And proliferation cell nuclear antigen (PCNA) indicated that the proliferation of NCCs was reduced. The mRNA expression of genes related to migration, proliferation, and differentiation of NCCs has changed significantly under OPP exposure. Astaxanthin (AST), a widely used antioxidant, could partially rescue the craniofacial cartilage development exposed to OPP. The results showed improvements in oxidative stress, gene transcription, NCCs proliferation, and protein expression in zebrafish, suggesting that OPP may reduce antioxidant capacity and subsequently inhibit migration, proliferation, and differentiation of the NCCs. In conclusion, our study found that OPP may produce reactive oxygen species, leading to developmental toxicity in zebrafish craniofacial cartilage.

Gut Microbiota is Associated with Aging-Related Processes of a Small Mammal Species under High-Density Crowding Stress.

Humans and animals frequently encounter high-density crowding stress, which may accelerate their aging processes; however, the roles of gut microbiota in the regulation of aging-related processes under high-density crowding stress remain unclear. In the present study, it is found that high housing density remarkably increases the stress hormone (corticosterone), accelerates aging-related processes as indicated by telomere length (in brain and liver cells) and DNA damage or inflammation (as revealed by tumor necrosis factor-α and interleukin-10 levels), and reduces the lifespan of Brandt's vole (Lasiopodomys brandtii). Fecal microbiota transplantation from donor voles of habitats with different housing densities induces similar changes in aging-related processes in recipient voles. The elimination of high housing density or butyric acid administration delays the appearance of aging-related markers in the brain and liver cells of voles housed at high-density. This study suggests that gut microorganisms may play a significant role in regulating the density-dependent aging-related processes and subsequent population dynamics of animals, and can be used as potential targets for alleviating stress-related aging in humans exposed to high-density crowding stress.

Behavior and physiology in female Cricetulus barabensis are associated with the expression of circadian genes.

The circadian clock regulates the behavior, physiology, and metabolism of mammals, and these characteristics, such as sleep-wake cycles, exercise capacity, and hormone levels, exhibit circadian rhythms. Light signaling is the main stimulator of the mammalian circadian system. The photoperiod regulates the reproductive cycle of seasonal breeding animals, and the circadian clock plays a pivotal role in this process. However, the role of the clock in coordinating animal behavior and physiology in response to photoperiodic changes needs further investigation. The present study investigated the changes and correlation of behavioral activities, physiological indicators, and gene expression in female striped hamsters (Cricetulus barabensis) within 24 h under a 12L:12D photoperiod. We found that the daily rhythms of sleep-wake and open field were significant in hamsters. The expression of clock genes, melatonin receptor genes, and genes involved in general metabolism oscillated significantly in central and peripheral tissues (brain, hypothalamus, liver, ovary, and thymus) and was significantly associated with behavior and physiology. Our results revealed that the neuroendocrine system regulated the rhythmicity of behavior and physiology, and central and peripheral clock genes (Bmal1, Clock, Per1, Per2, Cry1, and Cry2), melatonin receptor genes (MT1, MT2, and GPR50), and metabolizing genes (SIRT1, FGF21, and PPARα) played important roles. Our results suggest that central and peripheral circadian clocks, melatonin receptors, and genes involved in general metabolism may play key roles in maintaining circadian behavior and metabolic homeostasis in striped hamsters. Our results may have important implication for rodent pest control.

Gut microbiota is associated with the effect of photoperiod on seasonal breeding in male Brandt's voles (Lasiopodomys brandtii).

BACKGROUND: Seasonal breeding in mammals has been widely recognized to be regulated by photoperiod, but the association of gut microbiota with photoperiodic regulation of seasonal breeding has never been investigated. RESULTS: In this study, we investigated the association of gut microbiota with photoperiod-induced reproduction in male Brandt's voles (Lasiopodomys brandtii) through a long-day and short-day photoperiod manipulation experiment and fecal microbiota transplantation (FMT) experiment. We found photoperiod significantly altered reproductive hormone and gene expression levels, and gut microbiota of voles. Specific gut microbes were significantly associated with the reproductive hormones and genes of voles during photoperiod acclimation. Transplantation of gut microbes into recipient voles induced similar changes in three hormones (melatonin, follicle-stimulating hormone, and luteinizing hormone) and three genes (hypothalamic Kiss-1, testicular Dio3, and Dio2/Dio3 ratio) to those in long-day and short-day photoperiod donor voles and altered circadian rhythm peaks of recipient voles. CONCLUSIONS: Our study firstly revealed the association of gut microbiota with photoperiodic regulation of seasonal breeding through the HPG axis, melatonin, and Kisspeptin/GPR54 system. Our results may have significant implications for pest control, livestock animal breeding, and human health management. Video Abstract.

[Effects of piperphentonamine hydrochloride on cognitive deficits in rats induced by cerebral ischemia-reperfusion].

OBJECTIVE: To investigate the effect of piperphentonamine hydrochloride (PPTA) on cognitive deficits induced by ischemia-reperfusion and explore the possible mechanisms. METHODS: SD rats were randomly divided into sham-operated group, ischemia-reperfusion group (with saline injection), PPTA-treated groups (2.5, 5, 10 mg/kg) and edaravone-treated group (6 mg/kg). Cerebral ischemia-reperfusion injury was induced by middle cerebral artery occlusion, and the agents were administrated 1 h after ischemia. At 24 h after ischemia, step-through passive avoidance test was carried out, and 24 h later IL-1ß, TNF-α, caspase-3 and HSP-70 mRNA expressions in the ischemic brain tissues were measured with RT-PCR. RESULTS: In the step-through passive avoidance test, the rats in the ischemia-reperfusion group showed significantly shorter latency and more error times than those in the sham group, and these behavioral changes were improved significantly by treatments with PPTA and edaravone. Cerebral ischemia-reperfusion caused significantly increased expressions of IL-1ß, TNF-α, caspase-3 and HSP-70 mRNA, and these changes were obviously reversed by PPTA, but not by edaravone. CONCLUSIONS: PPTA can reverse cognitive deficits induced by cerebral ischemia-reperfusion probably by decreasing the inflammatory responses and cell apoptosis in the brain, suggesting its potential as a new therapeutic agent for improving the cognitive function following cerebral ischemia-reperfusion.