Chronic corticosterone disrupts the circadian rhythm of CRH expression and m6A RNA methylation in the chicken hypothalamus

Regulation and application of m6A modification in tumor immunity

The m6A modification is an RNA modification that impacts various processes of RNA molecules, including transcription, splicing, stability, and translation. Recently, researchers have discovered that the presence of m6A modification can influence the interaction between tumor cells and immune cells and also play a role in regulating the expression of immune response-related genes. Additionally, m6A modification is intricately involved in the regulation of tumor immune evasion and drug resistance. Specifically, certain tumor cells can manipulate the gene expression through m6A modification to evade immune system attacks. Therefore, it might be possible to enhance tumor immune surveillance and improve the effectiveness of immune-based therapies by manipulating m6A modification. This review systematically discusses the role of m6A modification in tumor immunity, specifically highlighting its regulation of immune cells and immune-related genes in tumor cells. Furthermore, we explore the potential of m6A modification inhibitors as anti-cancer therapies and the significance of m6A regulatory factors in predicting the efficacy of tumor immune therapy.

Mechanism of N6-Methyladenosine Modification in the Pathogenesis of Depression

N6-methyladenosine (m6A) is one of the most common post-transcriptional RNA modifications, which plays a critical role in various bioprocesses such as immunological processes, stress response, cell self-renewal, and proliferation. The abnormal expression of m6A-related proteins may occur in the central nervous system, affecting neurogenesis, synapse formation, brain development, learning and memory, etc. Accumulating evidence is emerging that dysregulation of m6A contributes to the initiation and progression of psychiatric disorders including depression. Until now, the specific pathogenesis of depression has not been comprehensively clarified, and further investigations are warranted. Stress, inflammation, neurogenesis, and synaptic plasticity have been implicated as possible pathophysiological mechanisms underlying depression, in which m6A is extensively involved. Considering the extensive connections between depression and neurofunction and the critical role of m6A in regulating neurological function, it has been increasingly proposed that m6A may have an important role in the pathogenesis of depression; however, the results and the specific molecular mechanisms of how m6A methylation is involved in major depressive disorder (MDD) were varied and not fully understood. In this review, we describe the underlying molecular mechanisms between m6A and depression from several aspects including inflammation, stress, neuroplasticity including neurogenesis, and brain structure, which contain the interactions of m6A with cytokines, the HPA axis, BDNF, and other biological molecules or mechanisms in detail. Finally, we summarized the perspectives for the improved understanding of the pathogenesis of depression and the development of more effective treatment approaches for this disorder.

Chronobiological and neuroendocrine insights into dry eye

Dry eye, a prevalent ocular surface disease, is significantly influenced by modern lifestyle factors such as night-shift work and extended screen time. Emerging evidence suggests a strong correlation between disturbances in circadian rhythm, sleep disorders, and dry eye. However, the precise underlying mechanisms remain unclear. Recent studies have underscored the crucial role of circadian rhythms and neuroendocrine regulation in maintaining ocular surface health. Advances in treatment strategies targeting neuroendocrine pathways have shown promising developments. This review explores the interplay between circadian rhythms, neuroendocrine regulation, and the ocular surface, examines the impact of circadian disruption on the pathophysiology of dry eye, and proposes intervention strategies to alleviate dry eye associated with disturbances in circadian rhythms.

RNA methylation in neurodevelopment and related diseases

Biological development and genetic information transfer are governed by genetic, epigenetic, transcriptional, and posttranscriptional mechanisms. RNA methylation, the attachment of methyl (-CH 3) groups to RNA molecules, is a posttranscriptional modification that has gained increasing attention in recent years because of its role in RNA epitranscriptomics. RNA modifications (RMs) influence various aspects of RNA metabolism and are involved in the regulation of diverse biological processes and diseases. Neural cell types emerge at specific stages of brain development, and recent studies have revealed that neurodevelopment, aging, and disease are tightly linked to transcriptome dysregulation. In this review, we discuss the roles of N6-methyladenine (m6A) and 5-methylcytidine (m5C) RNA modifications in neurodevelopment, physiological functions, and related diseases.

New horizons for the role of RNA N6-methyladenosine modification in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancy, presenting a formidable challenge to the medical community owing to its intricate pathogenic mechanisms. Although current prevention, surveillance, early detection, diagnosis, and treatment have achieved some success in preventing HCC and controlling overall disease mortality, the imperative to explore novel treatment modalities for HCC remains increasingly urgent. Epigenetic modification has emerged as pivotal factors in the etiology of cancer. Among these, RNA N6-methyladenosine (m6A) modification stands out as one of the most prevalent, abundant, and evolutionarily conserved post-transcriptional alterations in eukaryotes. The literature underscores that the dynamic and reversible nature of m6A modifications orchestrates the intricate regulation of gene expression, thereby exerting a profound influence on cell destinies. Increasing evidence has substantiated conspicuous fluctuations in m6A modification levels throughout the progression of HCC. The deliberate modulation of m6A modification levels through molecular biology and pharmacological interventions has been demonstrated to exert a discernible impact on the pathogenesis of HCC. In this review, we elucidate the multifaceted biological functions of m6A modifications in HCC, and concurrently advancing novel therapeutic strategies for the management of this malignancy.

Ramifications of m6A Modification on ncRNAs in Cancer

N6-methyladenosine (m6A) is an RNA modification wherein the N6-position of adenosine is methylated. It is one of the most prevalent internal modifications of RNA and regulates various aspects of RNA metabolism. M6A is deposited by m6A methyltransferases, removed by m6A demethylases, and recognized by reader proteins, which modulate splicing, export, translation, and stability of the modified mRNA. Recent evidence suggests that various classes of non- coding RNAs (ncRNAs), including microRNAs (miRNAs), circular RNAs (circRNAs), and long con-coding RNAs (lncRNAs), are also targeted by this modification. Depending on the ncRNA species, m6A may affect the processing, stability, or localization of these molecules. The m6A- modified ncRNAs are implicated in a number of diseases, including cancer. In this review, the author summarizes the role of m6A modification in the regulation and functions of ncRNAs in tumor development. Moreover, the potential applications in cancer prognosis and therapeutics are discussed.

Novel Insights into the Circadian Rhythms Based on Long Noncoding and Circular RNA Profiling

Circadian rhythm disorders pose major risks to human health and animal production activity, and the hypothalamus is the center of circadian rhythm regulation. However, the epigenetic regulation of circadian rhythm based on farm animal models has been poorly investigated. We collected chicken hypothalamus samples at seven time points in one light/dark cycle and performed long noncoding RNA (lncRNA), circular RNA (circRNA), and mRNA sequencing to detect biomarkers associated with circadian rhythm. We enhanced the comprehensive expression profiling of ncRNAs and mRNAs in the hypothalamus and found two gene sets (circadian rhythm and retinal metabolism) associated with the light/dark cycle. Noncoding RNA networks with circadian expression patterns were identified by differential expression and circadian analysis was provided that included 38 lncRNAs, 15 circRNAs, and 200 candidate genes. Three lncRNAs (ENSGALT00000098661, ENSGALT00000100816, and MSTRG.16980.1) and one circRNA (novel_circ_010168) in the ncRNA-mRNA regulatory network were identified as key molecules influencing circadian rhythm by regulating AOX1 in retinal metabolism. These ncRNAs were predicted to be related to pernicious anemia, gonadal, eye disease and other disorders in humans. Together, the findings of this study provide insights into the epigenetic mechanisms of circadian rhythm and reveal AOX1 as a promising target of circadian rhythm regulation.

Transcriptome-wide study revealed m6A and miRNA regulation of embryonic breast muscle development in Wenchang chickens

N⁶-Methyladenosine (m6A) modification has been shown to play important role in skeletal muscle development. Wenchang chickens are commonly used as a high-quality animal model in researching meat quality. However, there have been no previous reports regarding the profile of m6A and its function in the embryonic breast muscle development of Wenchang chickens. In this paper, we identified different developmental stages of breast muscle in Wenchang chickens and performed m6A sequencing and miRNA sequencing in the breast muscle of embryos. Embryo breast muscles were weighed and stained with hematoxylin–eosin after hatching. We found that myofibers grew fast on the 10^th day after hatching (E10) and seldom proliferated beyond the 19^th day after hatching (E19). A total of 6,774 differentially methylated genes (DMGs) were identified between E10 and E19. For RNA-seq data, we found 5,586 differentially expressed genes (DEGs). After overlapping DEGs and DMGs, we recorded 651 shared genes (DEMGs). Subsequently, we performed miRNA-seq analysis and obtained 495 differentially expressed miRNAs (DEMs). Then, we overlapped DEMGs and the target genes of DEMs and obtained 72 overlapped genes (called miRNA-m6A-genes in this study). GO and KEGG results showed DEMGs enriched in many muscle development-related pathways. Furthermore, we chose WNT7B, a key regulator of skeletal muscle development, to perform IGV visualization analysis and found that the m6A levels on the WNT7B gene between E10 and E19 were significantly different. In conclusion, we found that miRNAs, in conjunction with m6A modification, played a key role in the embryonic breast muscle development of Wenchang chickens. The results of this paper offer a theoretical basis for the study of m6A function in muscle development and fat deposition of Wenchang chickens.

Constant light in early life induces fear-related behavior in chickens with suppressed melatonin secretion and disrupted hippocampal expression of clock- and BDNF-associated genes

Background

Light management plays an important role in the growth and behavior of broiler chickens. Constant light in early post hatch stage has been a common practice in broiler industry for improving growth performance, while whether and how constant light in early life affects the behavior of broiler chickens is rarely reported.

Results

In this study, newly hatched chicks were kept in either constant (24 L:0 D, LL) or (12 L:12 D, LD) photoperiod for 7 d and then maintained in 12 L:12 D thereafter until 21 days of age. Constant light increased the average daily feed intake but not the body weight, which led to higher feed conversion ratio. Chickens in LL group exhibited fear-related behaviors, which was associated with higher corticosterone, lower melatonin and 5-HT levels. Concurrently, constant light exposure increased the mRNA expression of clock-related genes and suppressed the expression of antioxidative genes in the hippocampus. Moreover, brain derived neurotrophic factor/extracellular signal-regulated kinase (BDNF/ERK) pathway was suppressed in the hippocampus of chickens exposed to constant light in the first week post hatching.

Conclusions

These findings indicate that constant light exposure in early life suppress melatonin secretion and disrupts hippocampal expression of genes involved in circadian clock and BDNF/ERK pathway, thereby contributing to fear-related behaviors in the chicken.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00720-4.