RNA-seq analysis identifies age-dependent changes in expression of mRNAs - encoding N-glycosylation pathway enzymes in mouse gonadotropes

Identification of FSH-regulated and estrous stage-specific transcriptional networks in mouse ovaries

Follicle-stimulating hormone (FSH) acts by binding to FSHRs expressed on ovarian granulosa cells and produces estradiol. FSH is essential for female fertility because mice lacking FSH (Fshb KO) are anestrous and infertile. Although several in vitro cell culture and ex vivo approaches combined with pharmacological hormone treatment were used to identify FSH-regulated genes, how FSH orchestrates ovarian gene networks in vivo has not been investigated. Whether FSH-regulated genes display estrous stage-specific expression changes has also not been studied. Here, we functionally rescued Fshb null mice with a gonadotrope-targeted HFSHB transgene and performed RNA-Seq analysis on ovarian RNAs obtained from FSH-intact (WT), FSH-deficient (Fshb KO), and FSH-rescue (HFSHB+ rescue) mice. By comparing WT vs. Fshb KO and Fshb KO vs. HFSHB+ rescue ovarian gene expression datasets, we identified FSH-responsive genes in vivo. Cross interrogation of these datasets further allowed us to identify several transcription factors (TFs) and RNA-binding proteins specific to FSH-regulated genes. In an independent set of experiments, we performed RNA-Seq analysis on ovarian RNAs from mice in diestrous (DE), proestrous (PE), and estrous (E) and identified estrous stage-specific ovarian gene expression patterns. Interestingly, many of the FSH-regulated TFs themselves were estrous-stage specifically expressed. We found that ESR2 and GATA6, two known FSH-responsive TFs, and their target genes are reciprocally regulated with distinct patterns of expression in estrous stages. Together, our in vivo models and RNA-Seq analyses identify FSH-regulated ovarian genes in specific estrous stages that are under transcriptional and posttranscriptional control.

Glycosylation in aging and neurodegenerative diseases

Aging, a complex biological process, involves the progressive decline of physiological functions across various systems, leading to increased susceptibility to neurodegenerative diseases. In society, demographic aging imposes significant economic and social burdens due to these conditions. This review specifically examines the association of protein glycosylation with aging and neurodegenerative diseases. Glycosylation, a critical post-translational modification, influences numerous aspects of protein function that are pivotal in aging and the pathophysiology of diseases such as Alzheimer's disease, Parkinson's disease, and other neurodegenerative conditions. We highlight the alterations in glycosylation patterns observed during aging, their implications in the onset and progression of neurodegenerative diseases, and the potential of glycosylation profiles as biomarkers for early detection, prognosis, and monitoring of these age-associated conditions, and delve into the mechanisms of glycosylation. Furthermore, this review explores their role in regulating protein function and mediating critical biological interactions in these diseases. By examining the changes in glycosylation profiles associated with each part, this review underscores the potential of glycosylation research as a tool to enhance our understanding of aging and its related diseases.

Multiomics insights into the female reproductive aging

The human female reproductive lifespan significantly diminishes with age, leading to decreased fertility, reduced fertility quality and endocrine function disorders. While many aspects of aging in general have been extensively documented, the precise mechanisms governing programmed aging in the female reproductive system remain elusive. Recent advancements in omics technologies and computational capabilities have facilitated the emergence of multiomics deep phenotyping. Through the application and refinement of various high-throughput omics methods, a substantial volume of omics data has been generated, deepening our comprehension of the pathogenesis and molecular underpinnings of reproductive aging. This review highlights current and emerging multiomics approaches for investigating female reproductive aging, encompassing genomics, epigenomics, transcriptomics, proteomics, metabolomics, and microbiomics. We elucidate their influence on fundamental cell biology and translational research in the context of reproductive aging, address the limitations and current challenges associated with multiomics studies, and offer a glimpse into future prospects.

Oocyte quality is enhanced by hypoglycosylated FSH through increased cell-to-cell interaction during mouse follicle development

Macroheterogeneity in follicle-stimulating hormone (FSH) β-subunit N-glycosylation results in distinct FSH glycoforms. Hypoglycosylated FSH21 is the abundant and more bioactive form in pituitaries of females under 35 years of age, whereas fully glycosylated FSH24 is less bioactive and increases with age. To investigate whether the shift in FSH glycoform abundance contributes to the age-dependent decline in oocyte quality, the direct effects of FSH glycoforms on folliculogenesis and oocyte quality were determined using an encapsulated in vitro mouse follicle growth system. Long-term culture (10-12 days) with FSH21 (10 ng/ml) enhanced follicle growth, estradiol secretion and oocyte quality compared with FSH24 (10 ng/ml) treatment. FSH21 enhanced establishment of transzonal projections, gap junctions and cell-to-cell communication within 24 h in culture. Transient inhibition of FSH21-mediated bidirectional communication abrogated the positive effects of FSH21 on follicle growth, estradiol secretion and oocyte quality. Our data indicate that FSH21 promotes folliculogenesis and oocyte quality in vitro by increasing cell-to-cell communication early in folliculogenesis, and that the shift in in vivo abundance from FSH21 to FSH24 with reproductive aging may contribute to the age-dependent decline in oocyte quality.