Precocious puberty (PP) is a common pediatric endocrine disorder that affects children's growth and sexual development. Environmental pollutants, especially microplastics (MPs), may be an important triggering factors in PP. MPs were widely found in children's living environment, while the impact of MPs on pubertal development remains unknown. In this study, 14 serum samples were collected from central precocious puberty (CPP) girls and healthy controls. The concentration of total MPs in CPP girls (68.19 ± 26.49 mg/kg) showed significant increase than healthy controls (36.94 ± 13.22 mg/kg). 5 of 11 types of MPs were detected, among which PE (CPP, 28.22 %; Control, 31.62 %) and PVC (CPP, 62.67 %; Control, 58.14 %) being the dominant ones. Correlation analysis between MPs and sex hormone revealed that total MPs were negatively correlated with progesterone and positively correlated with dehydroepiandrosterone (DHEAS). In order to investigate the toxic effects of MPs on pubertal onset, young female mice at 21 days were orally administered various concentrations of MPs for two weeks. Female mice exposed to MPs (PE, 3 mg/day; PVC, 6 mg/day) had an advanced vaginal opening, while none significant changes in body weight. Immunohistochemical staining demonstrated that MPs exposure during puberty could activate microglia, astrocytes and promote GnRH expression in the hypothalamus, which leading to an earlier pubertal onset. These data suggested that MPs can be absorbed and accumulated in brain and gonad after gavage, and accelerate female pubertal initiation. This study provided valuable evidence that MPs threatened the normal progression of female pubertal development.

Background: Puberty is among the most important stages in human development. Timely activation of hypothalamic gonadotropin-releasing hormone (GnRH) neurons underlies the initiation of pubertal development. The fat mass and obesity-associated (FTO), which is expressed in the hypothalamus, may regulate the m6A methylation of its target genes, influencing GnRH expression in the hypothalamus during puberty onset. This study aimed to explore the mechanism by which FTO regulates the function of its target neurotrophins within the hypothalamus and to clarify the molecular pathway underlying precocious puberty. Methods: Methylated RNA immunoprecipitation sequencing (MeRIP-seq) was used to assess m6A methylation in the hypothalamus of female rats. Serum brain-derived neurotrophic factor (BDNF) levels were measured in girls with central precocious puberty (CPP) and matched controls. BDNF was applied to GnRH neurons in vitro . The functions of FTO were assessed through overexpression and knockdown in animal models, with downstream signaling evaluated via BDNF/PI3K/Akt pathway analysis. Intracerebroventricular (ICV) injections of a BDNF-overexpressing lentiviral vector or a negative control (NC) were used to investigate the role of central BDNF in regulating puberty onset and reproductive function. Results: Hypothalamic GnRH and FTO expression progressively increased whereas m6A methylation decreased during puberty. MeRIP-seq revealed significantly reduced m6A methylation of Bdnf mRNA in the arcuate nucleus (ARC) of female rats during early puberty. In the ARC, BDNF was expressed adjacent to GnRH-positive fibers and terminals. In addition, serum BDNF levels were higher in girls with CPP girls than in the control group. In vitro , BDNF treatment stimulated GnRH expression in GT1–7 cells. FTO positively regulated BDNF expression in an m6A methylation-dependent manner. FTO overexpression activated BDNF/PI3K/Akt signaling in the ARC and accelerated puberty onset. Conversely, FTO knockdown delayed vaginal opening and suppressed BDNF/PI3K/Akt signaling. ICV delivery of a BDNF-overexpressing lentivirus increased hypothalamic BDNF and GnRH expression, leading to a distinct endocrine profile. Conclusion: These findings suggest that FTO regulates the m6A demethylation of BDNF and promotes GnRH expression through the BDNF/PI3K/Akt signaling pathway. This study improves our understanding of the function of BDNF, which is critical for the development of therapeutic strategies for preventing and treating of precocious puberty.

Background: Kallmann syndrome (KS) is a genetic disorder characterized by impaired reproductive system and olfactory development. This study aimed to identify a novel variant of SEMA3A in a KS patient and explore its potential pathogenic mechanism. Methods: A gene panel was used to identify potential pathogenic mutations. Wild‐type and mutant SEMA3A overexpression plasmids were constructed. Western blotting, RNA sequencing, and cell migration were performed to assess the effects of SEMA3A gene variations on GnRH neuronal migration. Results: A novel heterozygous mutation in the SEMA3A gene (NM_006080.3: exon 6–9 deletion) was identified in the proband, as well as in his father and sister. The spatial structure of the SEMA3A mutant protein was relatively looser. In vitro experiments revealed that SEMA3A mutation reduced SEMA3A expression and inhibited GnRH neuronal migration. RNAseq analysis revealed that the expression of 76 genes was upregulated and that of 104 genes was downregulated after SEMA3A mutation. The altered gene clusters were enriched mainly in cell migration, male gonad development, motor proteins, and neuron synapses. Conclusions: In this study, we identified a novel variant of SEMA3A in a KS patient and verified its function. These findings expand the mutation spectrum of the SEMA3A gene and offer a theoretical basis for the clinical diagnosis of KS.

Backgrounds: Pediatric-onset primary ovarian insufficiency (POI) presents distinct clinical challenges, including delayed puberty or growth retardation. Previously, we reported a Chinese family with POI harboring compound heterozygous variants (p.C242R and p.S445*) in MCM8 gene, a critical factor for DNA repair and gonadal homeostasis. Objective: This study describes clinical findings of pediatric-onset POI patients with compound heterozygous MCM8 variants and investigates the in vitro functional consequences of an artificial double-mutant MCM8 construct harboring both p.C242R and p.S445*. Using this overexpression model, we assessed DNA damage response, protein interactions, and transcriptomic changes associated with the double-mutant MCM8. Methods: HeLa cell models were used to overexpress double-mutant (p.C242R and p.S445*) or wild-type MCM8. Functional consequences were evaluated using immunofluorescence staining, flow cytometry, and western blotting to assess DNA damage repair, cell cycle and apoptosis. Co-immunoprecipitation coupled with mass spectrometry (CoIP–MS/MS) was used to screen the disrupted protein interactome. Cut&Tag and mRNA-seq analyses were used to examine chromatin-binding-associated changes and transcriptomic alterations. Results: Ovarian tissues from POI patients exhibited reduced MCM8 expression and increased apoptosis. Cells expressing the artificial double-mutant MCM8 construct showed delayed resolution of DNA damage, as indicated by persistent γ-H2AX accumulation, and altered recruitment of DMC1 and RAD51. These changes were accompanied by S-phase accumulation and increased apoptosis. CoIP–MS/MS analysis identified altered interaction between double-mutant MCM8 and MCM6, suggesting possible changes in replication-associated protein interactions. Integrated CUT&Tag and RNA-seq analyses identified MCM8-associated chromatin-binding changes and transcriptomic alterations involving candidate genes enriched in ovarian survival and metabolic pathways, including the PI3K/AKT signaling pathway. Conclusions: These specific MCM8 variants are clinically associated with pediatric-onset POI. In vitro , expression of double-mutant MCM8 construct was associated with impaired DNA damage resolution, altered MCM8-associated protein interactions, transcriptomic alterations, cell-cycle disturbance, and increased apoptosis. These findings provide cellular observations that may help generate hypotheses regarding how MCM8 dysfunction could contribute to ovarian insufficiency.