Spermatogenesis is a highly ordered and spatiotemporally regulated developmental process in the male reproductive system, during which spermatogonial stem cells (SSCs), supported by the seminiferous tubule microenvironment, sequentially undergo mitosis, meiosis, and spermiogenesis to ultimately generate structurally intact spermatozoa. This complex process is accompanied by extensive transcriptional reprogramming, chromatin remodeling, and finely tuned post-transcriptional regulation. Precise control of RNA fate is therefore essential for maintaining the continuity and fidelity of spermatogenesis, and its disruption represents a major molecular basis of male infertility. N⁶-methyladenosine (m⁶A), the most abundant internal RNA modification in eukaryotes, has emerged as a critical regulator of post-transcriptional gene expression. m⁶A methyltransferases (“writers”) catalyze the addition of a methyl group to the N⁶ position of adenosine, m⁶A demethylases (“erasers”) remove the modification, and m⁶A-binding proteins (“readers”) recognize m⁶A-modified transcripts. Through the coordinated actions of these factors, m⁶A regulates transcript fate at multiple levels, including RNA splicing, nuclear export, stability, translation, and decay. Emerging evidence indicates that m⁶A-mediated regulation is essential across multiple stages of spermatogenesis, including SSC self-renewal and differentiation, meiotic progression, maintenance of chromosomal stability, and sperm morphogenesis. Beyond its intrinsic functions in germ cells, m⁶A also contributes to the regulation of the testicular microenvironment. In sertoli cells, m⁶A is involved in maintaining blood-testis barrier integrity, RNA processing, and paracrine signaling, thereby providing structural and metabolic support for germ cell development. In Leydig cells, m⁶A regulates steroidogenesis, particularly testosterone synthesis, and participates in cellular stress responses and metabolic homeostasis. Through these mechanisms, m⁶A indirectly influences spermatogenesis by modulating the functional state of testicular somatic cells, highlighting an integrated regulatory mode that combines cell-intrinsic and microenvironment-mediated effects. Notably, distinct classes of m⁶A regulators exhibit pronounced stage-specific functions and coordinated division of labor, collectively forming a multilayered and dynamic regulatory network. Writers often display dosage- and temporal window-dependent effects; erasers contribute to stage-specific demethylation and functional compensation; while readers function through a “switch-buffer” dual-layer architecture, and RNA-binding proteins (RBPs) participate in substrate selection and post-transcriptional regulation. Importantly, emerging evidence suggests that some m⁶A-related proteins can function through noncanonical mechanisms independent of m⁶A recognition, such as intrinsic RNA-binding activity, helicase function, or ribonucleoprotein complex assembly, thereby expanding the functional landscape of the m⁶A regulatory system. Dysregulation of m⁶A machinery can lead to multiple spermatogenic defects, including impaired SSC self-renewal, meiotic arrest, abnormal chromatin remodeling, and defective sperm formation, ultimately resulting in male infertility. Despite substantial advances, several critical questions remain unresolved, including the distinction between m⁶A-dependent and -independent mechanisms, the spatiotemporal dynamics of m⁶A modifications at single-cell resolution, and the coordination and antagonism among different regulatory factors. In this review, we systematically summarize the dual regulation of spermatogenesis by germ cell-intrinsic mechanisms and the testicular microenvironment, and delineate the molecular mechanisms and stage-specific functions of the dynamic m⁶A regulatory network. We further discuss the current limitations in the field and propose feasible experimental strategies for future investigation. Collectively, this work aims to provide a comprehensive framework for understanding the epitranscriptomic regulation of spermatogenesis and to offer theoretical insights into the pathogenesis and clinical management of male infertility.

Spermatogenesis is a highly ordered and spatiotemporally regulated developmental process in the male reproductive system, during which spermatogonial stem cells (SSCs), supported by the seminiferous tubule microenvironment, sequentially undergo mitosis, meiosis, and spermiogenesis to ultimately generate structurally intact spermatozoa. This complex process is accompanied by extensive transcriptional reprogramming, chromatin remodeling, and finely tuned post-transcriptional regulation. Precise control of RNA fate is therefore essential for maintaining the continuity and fidelity of spermatogenesis, and its disruption represents a major molecular basis of male infertility. N⁶-methyladenosine (m⁶A), the most abundant internal RNA modification in eukaryotes, has emerged as a critical regulator of post-transcriptional gene expression. m⁶A methyltransferases (“writers”) catalyze the addition of a methyl group to the N⁶ position of adenosine, m⁶A demethylases (“erasers”) remove the modification, and m⁶A-binding proteins (“readers”) recognize m⁶A-modified transcripts. Through the coordinated actions of these factors, m⁶A regulates transcript fate at multiple levels, including RNA splicing, nuclear export, stability, translation, and decay. Emerging evidence indicates that m⁶A-mediated regulation is essential across multiple stages of spermatogenesis, including SSC self-renewal and differentiation, meiotic progression, maintenance of chromosomal stability, and sperm morphogenesis. Beyond its intrinsic functions in germ cells, m⁶A also contributes to the regulation of the testicular microenvironment. In sertoli cells, m⁶A is involved in maintaining blood-testis barrier integrity, RNA processing, and paracrine signaling, thereby providing structural and metabolic support for germ cell development. In Leydig cells, m⁶A regulates steroidogenesis, particularly testosterone synthesis, and participates in cellular stress responses and metabolic homeostasis. Through these mechanisms, m⁶A indirectly influences spermatogenesis by modulating the functional state of testicular somatic cells, highlighting an integrated regulatory mode that combines cell-intrinsic and microenvironment-mediated effects. Notably, distinct classes of m⁶A regulators exhibit pronounced stage-specific functions and coordinated division of labor, collectively forming a multilayered and dynamic regulatory network. Writers often display dosage- and temporal window-dependent effects; erasers contribute to stage-specific demethylation and functional compensation; while readers function through a “switch-buffer” dual-layer architecture, and RNA-binding proteins (RBPs) participate in substrate selection and post-transcriptional regulation. Importantly, emerging evidence suggests that some m⁶A-related proteins can function through noncanonical mechanisms independent of m⁶A recognition, such as intrinsic RNA-binding activity, helicase function, or ribonucleoprotein complex assembly, thereby expanding the functional landscape of the m⁶A regulatory system. Dysregulation of m⁶A machinery can lead to multiple spermatogenic defects, including impaired SSC self-renewal, meiotic arrest, abnormal chromatin remodeling, and defective sperm formation, ultimately resulting in male infertility. Despite substantial advances, several critical questions remain unresolved, including the distinction between m⁶A-dependent and -independent mechanisms, the spatiotemporal dynamics of m⁶A modifications at single-cell resolution, and the coordination and antagonism among different regulatory factors. In this review, we systematically summarize the dual regulation of spermatogenesis by germ cell-intrinsic mechanisms and the testicular microenvironment, and delineate the molecular mechanisms and stage-specific functions of the dynamic m⁶A regulatory network. We further discuss the current limitations in the field and propose feasible experimental strategies for future investigation. Collectively, this work aims to provide a comprehensive framework for understanding the epitranscriptomic regulation of spermatogenesis and to offer theoretical insights into the pathogenesis and clinical management of male infertility.

Intraflagellar transport (IFT) is a core mechanism for ciliary assembly, length maintenance, ciliary proteome homeostasis and signal transduction. Most proteins required for ciliary structure and function are synthesized in the cytoplasm. Because the ciliary compartment is separated from the cell body by the selective barrier of the transition zone, these proteins cannot freely equilibrate between the cytoplasm and the cilium. Consequently, axonemal components, membrane proteins and signaling molecules must be actively imported into cilia, retrieved from the ciliary compartment, and recycled or degraded through highly ordered transport and sorting pathways. The IFT system is mainly composed of the IFT-A complex, IFT-B complex, kinesin-2, dynein-2 and the Bardet-Biedl syndrome protein complex (BBSome). Through coordinated anterograde and retrograde transport, these modules mediate the dynamic trafficking of different classes of ciliary cargoes. Anterograde transport delivers structural and membrane-associated components from the ciliary base toward the ciliary tip, whereas retrograde transport retrieves IFT components and selected cargoes back toward the ciliary base and cytoplasm. In this way, IFT not only supports the construction of the axoneme but also contributes to the maintenance of ciliary composition and the regulation of ciliary signaling activity. In recent years, advances in cryo-electron microscopy, in situ cryo-electron tomography and single-molecule imaging have greatly improved our understanding of the molecular mechanisms underlying IFT. These approaches have revealed how IFT trains are assembled at the ciliary base, how they move along axonemal microtubule tracks, how they undergo directional switching at the ciliary tip, and how cargoes are retrieved and recycled. Among the IFT modules, IFT-B acts as the major scaffold of IFT trains. It participates in cargo loading, motor coupling and initiation of anterograde transport. IFT-A is involved in retrograde transport, membrane protein adaptor function and train remodeling. The BBSome, through reversible association with the IFT system, regulates ciliary membrane protein sorting, signaling receptor clearance and renewal of the ciliary proteome. These functions indicate that the IFT machinery is not a simple linear transport pathway, but rather a dynamic and reconfigurable transport system. The conversion of transport direction is a key step in the IFT cycle. This process is closely associated with disassembly of anterograde trains, dissociation of kinesin-2, activation of dynein-2 at the ciliary tip and reassembly of retrograde trains. In terms of pathogenic mechanisms, IFT abnormalities may cause ciliopathies through four major pathways: defects in ciliary assembly and structure, abnormal localization of ciliary cargoes, dysregulation of signaling pathways, and impaired cargo unloading and retrieval. These defects can affect multiple organ systems, including the retina, kidney, skeleton, respiratory tract, reproductive system, and neuro-metabolic system. Current therapeutic strategies are still mainly based on symptomatic support and maintenance of organ function. Overall, IFT is a dynamic transport system jointly regulated by axonemal structure, motor activity, cargo selection and cellular signaling. It links ciliary architecture with protein turnover and signaling regulation, thereby playing a fundamental role in both ciliary homeostasis and ciliopathy pathogenesis. Further elucidation of IFT regulatory mechanisms and their relationships with disease phenotypes will help promote mechanism-based classification, genetic diagnosis and precision intervention for ciliopathies.

ObjectiveTo explore the mechanism by which aerobic exercise improves hippocampal neuroinflammation and learning and memory ability in brain-aged mice via interferon regulatory factor 7 (IRF7). MethodsA total of 60 male specific pathogen-free (SPF) C57BL/6J mice were enrolled in the experiment, including 30 young mice (2 months old) and 30 naturally aging mice (12 months old). Young mice and old mice were respectively randomly assigned to four groups: young control group (group C, n=15), young exercise group (group CE, n=15), and aging control group (group A, n=15), aging exercise group (group AE, n=15). Mice in the exercise groups received an 8-week continuous treadmill aerobic exercise intervention, while control mice were kept under routine feeding without exercise intervention. After the intervention, Barnes maze and Y-maze behavioral tests were performed to comprehensively assess the learning and memory abilities of each group of mice. Transmission electron microscopy was used to observe the ultrastructural morphological changes of hippocampal synapses. Western blot assay was utilized to detect the protein expression and phosphorylation levels of Janus kinase 1 (JAK1), signal transducer and activator of transcription 1 (STAT1), as well as the expression of postsynaptic density protein 95 (PSD95). Immunofluorescence staining was applied to quantify the fluorescence intensity of ionized calcium-binding adapter molecule 1 (IBA1) in hippocampal tissues. The expression levels of inflammatory cytokines including interferon-α (IFN-α), interferon-β (IFN-β), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were measured by enzyme-linked immunosorbent assay (ELISA). Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the mRNA expression level of IRF7, and DNA methylation assay was further conducted to analyze the methylation level of the IRF7 gene in mouse hippocampus. ResultsAt the molecular level, compared with group C, the protein expression levels of JAK1, STAT1, p‑JAK1, and p‑STAT1 in group A were significantly increased (P<0.05), whereas PSD95 expression was decreased (P<0.05). ELISA assays showed that the levels of IFN‑α, IFN‑β, TNF‑α, and IL‑1β were significantly elevated in group A (P<0.001). RT‑PCR analysis revealed that, compared with group C, the mRNA expression of IRF7 in group A was markedly upregulated (P<0.000 1), while the CpG methylation rate of the IRF7 promoter was significantly reduced (P<0.05). In contrast, all the above parameters in the AE group showed improvements relative to those in group A. Immunofluorescence staining indicated positive IBA1 expression in the brain tissues of group A mice. Exercise intervention reversed these abnormal changes. ConclusionIn aged mice, aerobic exercise induces hypermethylation of the IRF7 promoter region, suppresses IRF7 expression and activation of the downstream IFN‑I/JAK1/STAT1 signaling pathway, accompanied by alleviated neuroinflammation, improved learning and memory, and ameliorated brain aging-related phenotypes.

ObjectiveTo explore the molecular mechanism of aerobic exercise to improve hippocampal neuronal degeneration by regulating tryptophan metabolic pathway. Methods60 SPF-grade C57BL/6J male mice were divided into a young group (2 months old, n=30) and a senile group (12 months old, n=30), and each group was further divided into a control group (C/A group, n=15) and an exercise group (CE/AE group, n=15). An aerobic exercise program was used for 8 weeks. Learning memory ability was assessed by Y-maze, and anxiety-depression-like behavior was detected by absent field experiment. Hippocampal Trp levels were measured by GC-MS. Nissl staining was used to observe the number and morphology of hippocampal neurons, and electron microscopy was used to detect synaptic ultrastructure. ELISA was used to detect the levels of hippocampal Trp,5-HT, Kyn, KATs, KYNA, KMO, and QUIN; Western blot was used to analyze the activities of TPH2, IDO1, and TDO enzymes. ResultsGroup A mice showed significant decrease in learning and memory ability (P<0.05) and increase in anxiety and depressive behaviors (P<0.05); all of AE group showed significant improvement (P<0.05). Hippocampal Trp levels decreased in group A (P<0.05) and increased in AE group (P<0.05). Nidus vesicles were reduced and synaptic structures were degraded in group A (P<0.05), and both were significantly improved in group AE (P<0.05). The levels of Trp, 5-HT, KATs, and KYNA were decreased (P<0.05) and the levels of Kyn, KMO, and QUIN were increased (P<0.05) in group A. The activity of TPH2 was decreased (P<0.05), and the activities of IDO1 and TDO were increased (P<0.05). The AE group showed the opposite trend. ConclusionThe aging process significantly reduces the learning memory ability and increases the anxiety-depression-like behavior of mice, and leads to the reduction of the number of nidus vesicles and degenerative changes of synaptic structure in the hippocampus, whereas aerobic exercise not only effectively enhances the spatial learning memory ability and alleviates the anxiety-depression-like behavior of aging mice, but also improves the morphology and structure of neurons in hippocampal area, which may be achieved by the mechanism of regulating the tryptophan metabolic pathway.

OBJECTIVES: To study genotype-phenotype correlations in children with FGFR3 variants and to improve clinical recognition of related disorders. METHODS: Clinical data of 95 patients aged 0-18 years harboring FGFR3 variants, confirmed by whole‑exome sequencing at Shanghai Children's Medical Center from January 2012 to December 2023, were retrospectively reviewed. Detailed phenotypic characterization was performed for 22 patients with achondroplasia (ACH) and 10 with hypochondroplasia (HCH). RESULTS: Among the 95 patients, 52 (55%) had ACH, 24 (25%) had HCH, 9 (9%) had thanatophoric dysplasia, 3 (3%) had syndromic skeletal dysplasia, 2 (2%) had severe achondroplasia with developmental delay and acanthosis nigricans, and 5 (5%) remained unclassified. A previously unreported FGFR3 variant, c.1663G>T, was identified. All 22 ACH patients presented with disproportionate short stature accompanied by limb dysplasia, commonly with macrocephaly, a depressed nasal bridge, bowed legs, and frontal bossing; complications were present in 17 (77%). The 10 HCH patients predominantly exhibited disproportionate short stature with limb dysplasia and depressed nasal bridge. CONCLUSIONS ACH is the most frequent phenotype associated with FGFR3 variants, and missense variants constitute the predominant variant type. The degree of FGFR3 activation appears to correlate with the clinical severity of skeletal dysplasia.
Humans ; Receptor, Fibroblast Growth Factor, Type 3/genetics* ; Child ; Male ; Child, Preschool ; Female ; Infant ; Adolescent ; Dwarfism/genetics* ; Achondroplasia/genetics* ; Lordosis/genetics* ; Infant, Newborn ; Retrospective Studies ; Genetic Association Studies ; Bone and Bones/abnormalities* ; Phenotype ; Limb Deformities, Congenital

OBJECTIVE: To evaluate the efficacy and safety of Shexiang Tongxin Dropping Pill (STDP) in treating stable angina patients with phlegm-heat and blood-stasis syndrome by exercise duration and metabolic equivalents. METHODS: This multicenter, randomized, double-blind, placebo-controlled clinical trial enrolled stable angina patients with phlegm-heat and blood-stasis syndrome from 22 hospitals. They were randomized 1:1 to STDP (35 mg/pill, 6 pills per day) or placebo for 56 days. The primary outcome was the exercise duration and metabolic equivalents (METs) assessed by the standard Bruce exercise treadmill test after 56 days of treatment. The secondary outcomes included the total angina symptom score, Chinese medicine (CM) symptom scores, Seattle Angina Questionnaire (SAQ) scores, changes in ST-T on electrocardiogram and adverse events (AEs). RESULTS: This trial enrolled 309 patients, including 155 and 154 in the STDP and placebo groups, respectively. STDP significantly prolonged exercise duration with an increase of 51.0 s, compared to a decrease of 12.0 s with placebo (change rate: -11.1% vs. 3.2%, P<0.01). The increase in METs was significantly greater in the STDP group than in the placebo group (change: -0.4 vs. 0.0, change rate: -5.0% vs. 0.0%, P<0.01). The improvement of total angina symptom scores (25.0% vs. 0.0%), CM symptom scores (38.7% vs. 11.8%), reduction of nitroglycerin consumption (100.0% vs. 11.3%), and all domains of SAQ, were significantly greater with STDP than placebo (all P<0.01). The changes in Q-T intervals at 28 and 56 days from baseline were similar between the two groups (both P>0.05). Twenty-five participants (16.3%) with STDP and 16 (10.5%) with placebo experienced AEs (P=0.131), with no serious AEs observed. CONCLUSION STDP could improve exercise tolerance in patients with stable angina and phlegm-heat and blood stasis syndrome, with a favorable safety profile. (Registration No. ChiCTR-IPR-15006020).
Humans ; Double-Blind Method ; Drugs, Chinese Herbal/adverse effects* ; Male ; Female ; Middle Aged ; Angina, Stable/physiopathology* ; Aged ; Syndrome ; Treatment Outcome ; Placebos ; Tablets

OBJECTIVE: Hepatocellular carcinoma (HCC) is sensitive to ferroptosis, a new form of programmed cell death that occurs in most tumor types. However, the mechanism through which ferroptosis modulates HCC remains unclear. This study aimed to investigate the oncogenic role and prognostic value of FANCD2 and provide novel insights into the prognostic assessment and prediction of immunotherapy. METHODS: Using clinicopathological parameters and bioinformatic techniques, we comprehensively examined the expression of FANCD2 macroscopically and microcosmically. We conducted univariate and multivariate Cox regression analyses to identify the prognostic value of FANCD2 in HCC and elucidated the detailed molecular mechanisms underlying the involvement of FANCD2 in oncogenesis by promoting iron-related death. RESULTS: FANCD2 was significantly upregulated in digestive system cancers with abundant immune infiltration. As an independent risk factor for HCC, a high FANCD2 expression level was associated with poor clinical outcomes and response to immune checkpoint blockade. Gene set enrichment analysis revealed that FANCD2 was mainly involved in the cell cycle and CYP450 metabolism. CONCLUSION To the best of our knowledge, this is the first study to comprehensively elucidate the oncogenic role of FANCD2. FANCD2 has a tumor-promoting aspect in the digestive system and acts as an independent risk factor in HCC; hence, it has recognized value for predicting tumor aggressiveness and prognosis and may be a potential biomarker for poor responsiveness to immunotherapy.
Humans ; Carcinoma, Hepatocellular/diagnosis* ; Liver Neoplasms/diagnosis* ; Immunotherapy ; Fanconi Anemia Complementation Group D2 Protein/metabolism* ; Prognosis ; Male ; Female ; Middle Aged ; Biomarkers, Tumor/metabolism*

OBJECTIVE: To reveal the effects and potential mechanisms by which synaptic vesicle glycoprotein 2A (SV2A) influences the distribution of amyloid precursor protein (APP) in the trans-Golgi network (TGN), endolysosomal system, and cell membranes and to reveal the effects of SV2A on APP amyloid degradation. METHODS: Colocalization analysis of APP with specific tagged proteins in the TGN, ensolysosomal system, and cell membrane was performed to explore the effects of SV2A on the intracellular transport of APP. APP, β-site amyloid precursor protein cleaving enzyme 1 (BACE1) expressions, and APP cleavage products levels were investigated to observe the effects of SV2A on APP amyloidogenic processing. RESULTS: APP localization was reduced in the TGN, early endosomes, late endosomes, and lysosomes, whereas it was increased in the recycling endosomes and cell membrane of SV2A-overexpressed neurons. Moreover, Arl5b (ADP-ribosylation factor 5b), a protein responsible for transporting APP from the TGN to early endosomes, was upregulated by SV2A. SV2A overexpression also decreased APP transport from the cell membrane to early endosomes by downregulating APP endocytosis. In addition, products of APP amyloid degradation, including sAPPβ, Aβ _1-42, and Aβ _1-40, were decreased in SV2A-overexpressed cells. CONCLUSION These results demonstrated that SV2A promotes APP transport from the TGN to early endosomes by upregulating Arl5b and promoting APP transport from early endosomes to recycling endosomes-cell membrane pathway, which slows APP amyloid degradation.
Amyloid beta-Protein Precursor/genetics* ; Membrane Glycoproteins/genetics* ; Animals ; Protein Transport ; Nerve Tissue Proteins/genetics* ; Humans ; Mice ; Endosomes/metabolism* ; trans-Golgi Network/metabolism*

Aim To explore the protective effect of icariin on the damage of tight junctional function of Sertoli cells in naturally aging mice and the related mechanism.Methods 15-month-old C57BL/6J male mice were randomly divided into three groups:aging model group,low-dose and high-dose icariin treatment group(5 and 20 mg·kg-1).Another 1-month-old C57BL/6J male mice were considered as adult control group(n=10).The mice in adult control group and aging model group were given the vehicle(0.5％sodi-um carboxymethyl cellulose solution)by intragastric administration,while the mice in icariin-treated groups were given different concentrations of icariin,respec-tively.After continuous administration of icariin for three months,the testes and epididymis were immedi-ately removed,weighed,and the organ index was calcu-lated.Sperm viability and sperm concentration in epi-didymis were measured.The morphological changes of testes were observed by HE staining.The ultrastructur-al changes of tight junctions of Sertoli cells were ob-served by transmission electron microscopy.The ex-pression levels of tight junction-related proteins ZO-1,Occludin,and Claudin11 of testicular Sertoli cells were detected by Western blot.The expression and localiza-tion of ZO-1,Occludin,Raptor,Rictor,p-70S6K,and p-rps6 were detected by immunofluorescence.Results Compared with the aging model group,icariin signifi-cantly increased testicular weight and its index,and ep-ididymal index,improved sperm viability and increased sperm concentration in naturally aging mice.In addi-tion,icariin improved the degeneration of testicular morphology and the damage of ultrastructure of Sertoli cell tight junction with aging.Furthermore,Western blot results showed that icariin up-regulated the expres-sion of ZO-1 and Occludin,but had no significant effect on the expression of Claudin 11.Immunofluorescence assay showed that icariin up-regulated the expression of Rictor,and down-regulated the expression of p-70S6K,p-rps6 and Raptor.Conclusions Icariin improves the tight junction damage of Sertoli cells in naturally aging mice,and its mechanism may be related to restoring the balance between mTORC1 and mTORC2.