Electroacupuncture attenuates ac4C modification of P16 mRNA in the ovarian granulosa cells of a mouse model premature ovarian failure

The up-regulation of RIPK3 mediated by ac4C modification promotes oxidative stress-induced granulosa cell senescence by inhibiting the Nrf2/HO-1 pathway

Abnormality of granulosa cells (GCs) is the critical cause of follicular atresia in premature ovarian failure (POF). RIPK3 is highly expressed in GCs derived from atretic follicles. We focus on uncovering how RIPK3 contributes to ovarian GC senescence. Primary GCs were treated with H₂O₂ to induce senescence. ROS was detected via DCFH-DA staining. Levels of senescence-related molecules and SA-β-Gal activity were examined. Cyclophosphamide was administered to mice to induce POF. The impact of RIPK3 on atretic follicles and sex hormones was evaluated through HE staining and ELISA, respectively. The acRIP-qPCR analysis of RIPK3 ac4C levels, RIP detection for interaction between RIPK3 and NAT10, and actinomycin D treatment to detect RIPK3 degradation were conducted. In H2O2-treated GCs and POF mouse ovaries, levels of RIPK3, ROS, senescence-related molecules, as well as SA-β-Gal activity, were all up-regulated, and this effect was suppressed by RIPK3 inhibition. RIPK3 interference reduced atretic follicles and FSH levels while increasing AMH and E2 levels. Nrf2 and HO-1 content were diminished in the models, whereas si-RIPK3 facilitated their expression. The effect of si-RIPK3 on decreased levels of ROS and senescence-related molecules was reversed by ML385. H2O2 decreased RIPK3 mRNA degradation and increased its ac4C modification. The ac4C modifying enzyme NAT10 was up-regulated in the models, and NAT10 enhanced RIPK3 mRNA stability through ac4C modification. NAT10 knockdown mitigated ovarian GC senescence by inhibiting RIPK3 expression. The promotion of RIPK3 mRNA stability through ac4C modification by NAT10, in turn, affects the Nrf2/HO-1 pathway and promotes ovarian GC senescence.

Advances of NAT10 in diseases: insights from dual properties as protein and RNA acetyltransferase

N-acetyltransferase 10 (NAT10) is a member of the Gcn5-related N-acetyltransferase (GNAT) family and it plays a crucial role in various cellular processes, such as regulation of cell mitosis, post-DNA damage response, autophagy and apoptosis regulation, ribosome biogenesis, RNA modification, and other related pathways through its intrinsic protein acetyltransferase and RNA acetyltransferase activities. Moreover, NAT10 is closely associated with the pathogenesis of tumors, Hutchinson-Gilford progeria syndrome (HGPS), systemic lupus erythematosus, pulmonary fibrosis, depression and host-pathogen interactions. In recent years, mRNA acetylation has emerged as a prominent focus of research due to its pivotal role in regulating RNA stability and translation. NAT10 stands out as the sole identified modification enzyme responsible for RNA acetylation. There remains some ambiguity regarding the similarities and differences in NAT10's actions on protein and RNA substrates. While NAT10 involves acetylation modification in both cases, which is a crucial molecular mechanism in epigenetic regulation, there are significant disparities in the catalytic mechanisms, regulatory pathways, and biological processes involved. Therefore, this review aims to offer a comprehensive overview of NAT10 as a protein and RNA acetyltransferase, covering its basic catalytic features, biological functions, and roles in related diseases.

Acupuncture: An Overview on Its Functions, Meridian Pathways and Molecular Mechanisms

Recent research has extensively explored the intricate mechanisms that underlie the effectiveness of acupuncture, highlighting the importance of stimulating acupoints, the role of acupuncture techniques in managing diseases, and the interaction between meridian pathways and molecular processes. Studies have underscored the crucial role of acupuncture in activating neurons, modulating the immune system, and influencing vascular activity, all of which contribute significantly to its therapeutic benefits across a wide range of symptoms and conditions. Utilization of imaging modalities enables the identification of changes in cerebral blood flow, brain function, and regional glucose metabolism following acupuncture sessions. The interstitial fluid circulation network within meridians adheres to specific laws that facilitate the transportation of materials. Acupuncture initiates the release of neurotransmitters, neuropeptides, and immune factors, impacting pain perception, inflammation, and physiological functions. It influences the complex neuro-endocrine-immune network by activating pathways involving the nervous system, the hypothalamic-pituitary-adrenal axis, and immune responses. Moreover, acupuncture induces molecular modifications such as phosphorylation, methylation, and histone modification, leading to key molecular changes that ultimately result in anti-inflammatory effects and the regulation of immune responses.

The clinical value of acupuncture for women with premature ovarian insufficiency: a systematic review and meta-analysis of randomized controlled trials

Objective

The aim of this study was to evaluate the therapeutic implications of acupuncture on improving ovarian function in women diagnosed with premature ovarian insufficiency (POI) through the implementation of randomized clinical trials (RCTs).

Methods

A comprehensive search of eight databases was conducted to identify RCTs up until 5 October 2023. The outcomes included the levels of sex hormones, antral follicle count (AFC), Kupperman score, and total effective rate. The risk of bias (RoB) tool was utilized to evaluate the quality of the included studies. In order to guarantee the robustness and reliability of the findings, subgroup and sensitivity analyses were performed to investigate potential sources of heterogeneity.

Results

A total of 13 RCTs comprising 775 patients were included in the study. Acupuncture demonstrated significant efficacy in reducing follicle-stimulating hormone (FSH) [SMD = 0.83, 95% CI (0.27, 1.39), I 2 = 92%, p = 0.004], enhancing estradiol levels (E2) [SMD = 0.50, 95% CI (0.07, 0.93), p = 0.02, I 2 = 87%], and increasing anti-Müllerian hormone (AMH) [SMD = 0.24, 95% CI (0.05, 0.44), p = 0.01, I 2 = 8%], as well as improving the overall effective rate [RR = 1.22, 95% CI (1.10, 1.35), p < 0.01, I 2 = 14%]. Subgroup analysis revealed that compared with non-acupuncture therapy, the acupuncture with Chinese herbal medicine (CHM) and hormone replacement therapy (HRT) group exhibited a substantial reduction in FSH levels [SMD = 1.02, 95% CI (0.52, 1.51), I 2 = 60%, p < 0.01]. Furthermore, the acupuncture with CHM group also exhibited a substantial reduction [SMD = 4.59, 95% CI (1.53, 7.65), I 2 = 98%, p < 0.01]. However, only the acupuncture with CHM and HRT group demonstrated a significant increase in E2 levels [SMD = 0.55, 95% CI (0.23, 0.87), I 2 = 12%, p < 0.01].

Conclusion

Acupuncture has demonstrated superiority over non-acupuncture in diminishing serum FSH levels and increasing serum E2, AMH, and the overall efficacy rate in women diagnosed with POI. These research findings suggest the necessity for broader-scale research with meticulous designs to fully demonstrate the efficacy and safety of acupuncture in the treatment of women with POI.

Systematic review registration

https://www.crd.york.ac.uk, identifier CRD42023467751.

CDKN2A promoter methylation enhances self-renewal of glioblastoma stem cells and confers resistance to carmustine

BACKGROUND

Glioblastoma, a highly aggressive form of brain cancer, poses significant challenges due to its resistance to therapy and high recurrence rates. This study aimed to investigate the expression and functional implications of CDKN2A, a key tumor suppressor gene, in glioblastoma cells, building upon the existing background of knowledge in this field.

METHOD

Quantitative reverse transcription PCR (qRT-PCR) analysis was performed to evaluate CDKN2A expression in U87 glioblastoma cells compared to normal human astrocytes (NHA). CDKN2A expression levels were manipulated using small interfering RNA (siRNA) and CDKN2A overexpression vector. Cell viability assays and carmustine sensitivity tests were conducted to assess the impact of CDKN2A modulation on glioblastoma cell viability and drug response. Sphere formation assays and western blot analysis were performed to investigate the role of CDKN2A in glioblastoma stem cell (GSC) self-renewal and pluripotency marker expression. Additionally, methylation-specific PCR (MSP) assays and demethylation treatment were employed to elucidate the mechanism of CDKN2A downregulation in U87 cells.

RESULT

CDKN2A expression was significantly reduced in glioblastoma cells compared to NHA. CDKN2A overexpression resulted in decreased cell viability and enhanced sensitivity to carmustine treatment. CDKN2A inhibition promoted self-renewal capacity and increased pluripotency marker expression in U87 cells. CDKN2A upregulation led to elevated protein levels of p16INK4a, p14ARF, P53, and P21, which are involved in cell cycle regulation. CDKN2A downregulation in U87 cells was associated with high promoter methylation, which was reversed by treatment with a demethylating agent.

CONCLUSION

Our findings demonstrate that CDKN2A downregulation in glioblastoma cells is associated with decreased cell viability, enhanced drug resistance, increased self-renewal capacity, and altered expression of pluripotency markers. The observed CDKN2A expression changes are mediated by promoter methylation. These results highlight the potential role of CDKN2A as a therapeutic target and prognostic marker in glioblastoma.

Emerging roles of RNA ac4C modification and NAT10 in mammalian development and human diseases

RNA ac4C modification is a novel and rare chemical modification observed in mRNA. Traditional biochemical studies had primarily associated ac4C modification with tRNA and rRNA until in 2018, Arango D et al. first reported the presence of ac4C modification on mRNA and demonstrated its critical role in mRNA stability and translation regulation. Furthermore, they established that the ac4C modification on mRNA is mediated by the classical N-acetyltransferase NAT10. Subsequent studies have underscored the essential implications of NAT10 and mRNA ac4C modification across both physiological and pathological regulatory processes. In this review, we aimed to explore the discovery history of RNA ac4C modification, its detection methods, and its regulatory mechanisms in disease and physiological development. We offer a forward-looking examination and discourse concerning the employment of RNA ac4C modification as a prospective therapeutic strategy across diverse diseases. Furthermore, we comprehensively summarize the functions and mechanisms of NAT10 in gene expression regulation and pathogenesis independent of RNA ac4C modification.

Loss of p16 does not protect against premature ovarian insufficiency caused by alkylating agents

BACKGROUND

Chemical agents such as alkylating agents (AAs) that are commonly used for the treatment of cancer cause great damage to the ovaries, thereby significantly increasing the risk of premature ovarian insufficiency (POI). However, the exact molecules underlying AA-induced POI remain largely obscure. Upregulation of the p16 gene may contribute to the progression of POI. As yet, no in vivo data from p16-deficient (KO) mice are available to demonstrate a critical role of p16 in POI. In the present study, we employed p16 KO mice to investigate whether loss of p16 could protect against POI caused by AAs.

METHODS

WT mice and their p16 KO littermates received a single dose of BUL + CTX to establish an AA-induced POI mouse model. One month later, oestrous cycles were monitored. Three months later, some of the mice were sacrificed to collect sera for measurements of hormone levels and ovaries for measurements of follicle counts, the proliferation and apoptosis of granulosa cells, ovarian stromal fibrosis and vessels. The remaining mice were mated with fertile males for the fertility test.

RESULTS

Our results showed that treatment with BUL + CTX significantly disrupted the oestrous cycles, increased the levels of FSH and LH while decreasing the levels of E2 and AMH, decreased the counts of primordial follicles and growing follicles while increasing the counts of atretic follicles, reduced the vascularized area in the ovarian stroma, and decreased fertility. All of these results were comparable between WT and p16 KO mice treated with BUL + CTX. In addition, ovarian fibrosis was not increased significantly in WT and p16 KO mice treated with BUL + CTX. Growing follicles with normal appearance had normally proliferating granulosa cells (without apparent apoptosis).

CONCLUSION

We concluded that genetic ablation of the p16 gene did not attenuate ovarian damage or help preserve the fertility of mice challenged by AAs. This study demonstrated for the first time that p16 is dispensable for AA-induced POI. Our preliminary findings suggest that targeting p16 alone may not preserve the ovarian reserve and fertility of females treated with AAs.

Stem cell-derived extracellular vesicles: A novel and potential remedy for primary ovarian insufficiency

Primary ovarian insufficiency (POI) is an essential cause of young female fertility loss. At present, there are many treatments for primary ovarian insufficiency, but due to the complexity of the pathogenesis of primary ovarian insufficiency, the efficacy still could not be satisfactory. Stem cell transplantation is a feasible intervention protocol for primary ovarian insufficiency. However, its wide application in the clinic is limited by some defects such as tumorigenic and controversial ethical issues. Stem cell-derived extracellular vesicles (EVs) represent an important mode of intercellular communication attracting increasing interest. It is well documented that stem cell-derived extracellular vesicles for primary ovarian insufficiency with exciting therapeutic effects. Studies have found that stem cell-derived extracellular vesicles could improve ovarian reserve, increase the growth of follicles, reduce follicle atresia, and restore hormone levels of FSH and E2. Its mechanisms include inhibiting ovarian granulosa cells (GCs) apoptosis, reactive oxygen species, and inflammatory response and promoting granulosa cells proliferation and angiogenesis. Thus, stem cell-derived extracellular vesicles are a promising and potential method for primary ovarian insufficiency patients. However, stem cell-derived extracellular vesicles are still a long way from clinical translation. This review will provide an overview of the role and the mechanisms of stem cell-derived extracellular vesicles in primary ovarian insufficiency, and further elaborate on the current challenges. It may suggest new directions for future research.

Electroacupuncture May Inhibit Oxidative Stress of Premature Ovarian Failure Mice by Regulating Intestinal Microbiota

Premature ovarian failure (POF) is the leading cause of female infertility, and there is no optimal treatment or medication available currently. For POF, electroacupuncture (EA) has been considered a promising therapeutic approach, but the mechanism for this is not clear. In this study, we explored the effects of EA (CV4, ST36, and SP6) on oxidative stress and intestinal microbiota of high-fat and high-sugar- (HFHS-) induced POF mice. The development of mice follicles was observed by hematoxylin and eosin (HE) staining. The serum levels of estrone (E1), estrogen (E2), estriol (E3), and 21-deoxycortisol (21D) were measured by the HPLC-MS/MS method. The concentrations of Fe2+, superoxide dismutase (SOD), hydroxyl radical (·OH), glutathione (GSH), superoxide anion, and malondialdehyde (MDA) were measured by spectrophotometry. The 16S-rDNA sequencing was used to measure many parameters related to the host gut bacteriome and mycobiome composition, relative abundance, and diversity. mRNA expression levels of ferroptosis-related genes were determined by RT-qPCR. After 4 weeks of EA intervention in POF mice, mature follicles were increased and the levels of the sex hormone were improved. SOD activities, antisuperoxide activities, and GSH increased while MDA, ·OH, and Fe2+ decreased. In addition, EA also altered the intestinal microbiota. These results reveal that EA can effectively inhibit ovarian oxidative stress and the accumulation of Fe2+ in POF mice. It may be that the alteration in the intestinal microbiota is one of the potential mechanisms of EA treatment. These findings suggest that EA has clinical potential as a safe treatment for POF.