Protein palmitoylation-mediated palmitic acid sensing causes blood-testis barrier damage via inducing ER stress

Palmitic Acid Accelerates Endothelial Cell Injury and Cardiovascular Dysfunction via Palmitoylation of PKM2

High serum level of palmitic acid(PA) is implicated in pathogenesis of cardiovascular diseases. PA serves as the substrate for protein palmitoylation. However, it is still unknown whether palmitoylation is involved in PA-induced cardiovascular dysfunction. Here, in clinical cohort studies of 1040 patients with coronary heart disease, high level of PA is associated with risk of major adverse cardiovascular events (MACE) and death. In ApoE-/-mice, 10 mg/kg-1 PA treatment induces blood pressure elevation, cardiac contractile dysfunction, endothelial dysfunction and atherosclerotic plaqueformation. In endothelial cells, inhibition of palmitoylation bypalmitoyl-transferase inhibitor 2-BP eliminates PA-induced endothelial injury, whereas promotion of palmitoylation by depalmitoylase inhibitor ML349 exacerbates the harmful effect of PA. Palmitoyl-proteomics analysis identifies pyruvate kinase isozyme type M2 (PKM2) as the palmitoylated protein responsible for PA-induced endothelial injury, and Cys31 as the predominant palmitoylated site. PKM2-C31S mutants (cysteine replaced by serine) prevents PA-induced endothelial injury. Endothelial-specific AAV-C31S PKM2endo ameliorates cardiovascular dysfunction caused by PA in ApoE-/- mice. Mechanistically, PKM2-C31 palmitoylation impairs PKM2 tetramerization to inhibit its pyruvate kinase activity and endothelial glycolysis. Finally, zDHHC13 is identified as the palmitoyl acyltransferase of PKM2. In conclusion, these findings suggest that PKM2-C31 palmitoylation contributes to PA-induced endothelial injury and cardiovascular dysfunction.

Reticulophagy promotes EMT-induced fibrosis in offspring's lung tissue after maternal exposure to carbon black nanoparticles during gestation by a m5C-dependent manner

Accumulating evidence indicates that maternal exposure to carbon black nanoparticles (CBNPs) during gestation can induce multiple system abnormalities in offspring, whereas its potential mechanism in respiratory disease is still largely unknown. In order to explore the effect of maternal exposure to CBNPs on offspring's lung and latent pathogenesis, we respectively established in vivo model of pregnant rats exposed to CBNPs and ex vivo model of lung epithelial cells treated with pups' serum of pregnant rats exposed to CBNPs. After maternal exposure to CBNPs, epithelial-mesenchymal transition (EMT) and fibrosis levels increased as a result of DDRGK1-mediated reticulophagy upregulated in offspring's lung. DDRGK1 as FAM134B's cargo bound with FAM134B to mediate reticulophagy. Transcription factor "SP1" positively regulated DDRGK1 gene expression by binding to its promoter. Furthermore, the upregulation of NSUN2 elevated m5C methylation of SP1 mRNA and the protein level of SP1 subsequently increased through Ybx1 recognizing and stabilizing m5C-methylated SP1 mRNA, followed by the increased levels of reticulophagy and fibrosis in lung epithelial cells treated with offspring's serum of matrix exposed to CBNPs during gestation. In conclusion, NSUN2/Ybx1/m5C-SP1 axis promoted DDRGK1-mediated reticulophagy, which played an important role in EMT-induced fibrosis in offspring's lung tissue after maternal exposure to CBNPs during gestation.

Assessing the Effects of Palm Oil Consumption on Life Expectancy, Metabolic Markers, and Oxidative Stress in Drosophila melanogaster

Palm oil is the world's second most consumed vegetable oil, sourced from the tropical palm tree Elaeis guineensis. Its consumption has been associated with a higher incidence of cardiovascular disease, largely due to its elevated palmitic acid content, however those studies are contradictory and inconclusive. Wishing to contribute to this issue, the present study aims to investigate the molecular and toxicological effects of this oil and the involvement of oxidative stress, given its role in metabolic dysfunctions using Drosophila melanogaster. This study examines survival rates, and locomotor performance, oxidative status by analysis of lipid peroxidation, ROS formation, thiol levels and antioxidant enzyme activity, and metabolic parameters such as cholesterol and triglycerides, glucose, trehalose and glycogen levels. Exposure to palm oil concentrations of 10% and 30% resulted in a shortened lifespan, reduced locomotor performance, and increased lipid peroxidation, with lower thiol levels and antioxidant enzyme modulation. Cholesterol levels was increased whereas energetic fuels as glucose and glycogen and trehalose were decreased mainly after 10 days of exposure. These findings underscore the detrimental effects of high-fat diets containing palm oil on lifespan, antioxidant defenses, and metabolism in Drosophila melanogaster. This data highlights the potential risk associated with the habitual consumption of palm oil in the daily diet by population, particularly concerning cardiovascular health and metabolic function.

Environmental toxins and reproductive health: unraveling the effects on Sertoli cells and the blood-testis barrier in animals†

Environmental pollution is an inevitable ecological issue accompanying the process of socialization, with increasing attention to its impacts on individual organisms and ecological chains. The reproductive system, responsible for transmitting genetic material in animals, is one of the most sensitive systems to environmental toxins. Research reveals that Sertoli cells are the primary target cells for the action of environmental toxins. Different environmental toxins mostly affect the blood-testis barrier and lead to male reproductive disorders by disrupting Sertoli cells. Therefore, this article provides an in-depth exploration of the toxic mechanisms of various types of environmental toxins on the male testes. It reveals the dynamic processes of tight junctions in the blood-testis barrier affected by environmental toxins and their specific roles in the reconstruction process.

The role of S-palmitoylation of C4BPA in regulating murine sperm motility and complement resistance

The epididymis and epididymosomes are crucial for regulating sperm motility, a key factor in male fertility. Palmitoylation, a lipid modification involving the attachment of palmitic acid to cysteine residues, is essential for protein function and localization. Additionally, this modification plays a vital role in the sorting of proteins into exosomes. This study investigates the role of S-palmitoylation at the Cys15 residue of the C4b binding protein alpha chain (C4BPA) in murine sperm motility. Our findings revealed high expression of C4BPA mRNA in the caput epididymis, with the protein present across all regions of the epididymis. Palmitoylation of C4BPA in epididymal epithelial cells was essential for its enrichment in epididymosomes and on sperm, thereby maintaining sperm motility. Inhibition of palmitoylation significantly reduced sperm motility and the localization of C4BPA on sperm. Additionally, palmitoylated C4BPA in exosomes resisted complement C4 attacks, preserving motility, unlike mutated C4BPA (C15S). These results highlight the critical role of palmitoylated C4BPA in protecting sperm from complement attacks and maintaining motility, suggesting that reversible palmitoylation of epididymal proteins could be explored as a therapeutic strategy for male contraception. Our study underscores the importance of post-translational modifications in sperm function and presents new insights into potential male contraceptive methods.

2-Bromopalmitate-Induced Intestinal Flora Changes and Testicular Dysfunction in Mice

2-Bromopalmitate (2-BP) is a palmitoylation inhibitor that can prevent the binding of palmitic acid to proteins, thereby exhibiting significant effects in promoting inflammation and regulating the immune system. However, limited research has been conducted regarding the direct effects of 2-BP on the animal organism. Therefore, we probed mice injected with 2-BP for altered expression of inflammatory genes, with a focus on demonstrating changes in the intestinal flora as well as damage to the reproductive system. Our findings indicate that 2-BP can induce substantial inflammatory responses in visceral organs and cause testicular dysfunction. The key changes in the gut microbiota were characterized by an abundance of Firmicutes, Clostridiales, Rikenellaceae_RC9_gut_group, Desulfovibrio, Muribaculaceae, and Alistipes, and their metabolism has been intricately linked to visceral inflammation. Overall, the findings of this study provide a sound scientific basis for understanding the impact of high doses of 2-BP in mammals, while also offering crucial support for the development of preclinical models to suppress palmitoylation.

Suppressed testicular macrophage M1 polarization by HDAC5 enforces insensitivity to LPS-elicited blood-testis barrier damage

Infertility caused by lipopolysaccharide (LPS) exposure due to infection is endangering male fertility worldwide, but the mechanism remains unclear. The blood-testis barrier (BTB) is essential for maintaining spermatogenesis and male fertility. In the present study, we showed that LPS (5.0 mg/kg) treatment markedly down-regulated the expression of BTB-related proteins, expanded the biotin penetration distance and caused histopathological injury in seminiferous tubules in mouse testes. Notably, testicular macrophage M1 polarization induced by LPS seems to be related to BTB damage, which was well confirmed by co-culture of RAW264.7 and TM4 cells in vitro. Interestingly, a low-dose LPS (0.1 mg/kg) pretreatment attenuated down-regulation of BTB-related proteins expression and histopathological injury and shorten biotin penetration distance in seminiferous tubules caused by LPS. Correspondingly, a low-dose LPS pretreatment suppresses testicular macrophage M1 polarization induced by LPS in mouse testes. Further experiments revealed that histone deacetylase 5 (HDAC5) was markedly down-regulated at 2 h and slightly down-regulated at 8 h, but up-regulated at 24 h in mouse testes after LPS treatment. Additionally, low-dose LPS pretreatment against the down-regulation of HDAC5 protein caused by LPS treatment. Notably, the suppressed testicular macrophage M1 polarization by low-dose LPS pretreatment was broken by BRD4354, a specific inhibitor of HDAC5 in vitro. These results suggest suppressed testicular macrophage M1 polarization by HDAC5 enforces insensitivity to LPS-elicited BTB damage.

Lipid droplets sequester palmitic acid to disrupt endothelial ciliation and exacerbate atherosclerosis in male mice

Disruption of ciliary homeostasis in vascular endothelial cells has been implicated in the development of atherosclerosis. However, the molecular basis for the regulation of endothelial cilia during atherosclerosis remains poorly understood. Herein, we provide evidence in male mice that the accumulation of lipid droplets in vascular endothelial cells induces ciliary loss and contributes to atherosclerosis. Triglyceride accumulation in vascular endothelial cells differentially affects the abundance of free fatty acid species in the cytosol, leading to stimulated lipid droplet formation and suppressed protein S-palmitoylation. Reduced S-palmitoylation of ciliary proteins, including ADP ribosylation factor like GTPase 13B, results in the loss of cilia. Restoring palmitic acid availability, either through pharmacological inhibition of stearoyl-CoA desaturase 1 or a palmitic acid-enriched diet, significantly restores endothelial cilia and mitigates the progression of atherosclerosis. These findings thus uncover a previously unrecognized role of lipid droplets in regulating ciliary homeostasis and provide a feasible intervention strategy for preventing and treating atherosclerosis.

ZDHHC9-mediated Bip/GRP78 S-palmitoylation inhibits unfolded protein response and promotes bladder cancer progression

Recent studies have highlighted palmitoylation, a novel protein post-translational modification, as a key player in various signaling pathways that contribute to tumorigenesis and drug resistance. Despite this, its role in bladder cancer (BCa) development remains inadequately understood. In this study, ZDHHC9 emerged as a significantly upregulated oncogene in BCa. Functionally, ZDHHC9 knockdown markedly inhibited tumor proliferation, promoted tumor cell apoptosis, and enhanced the efficacy of gemcitabine (GEM) and cisplatin (CDDP). Mechanistically, SP1 was found to transcriptionally activate ZDHHC9 expression. ZDHHC9 subsequently bound to and palmitoylated the Bip protein at cysteine 420 (Cys420), thereby inhibiting the unfolded protein response (UPR). This palmitoylation at Cys420 enhanced Bip's protein stability and preserved its localization within the endoplasmic reticulum (ER). ZDHHC9 might become a novel therapeutic target for BCa and could also contribute to combination therapy with GEM and CDDP.

Buriti (Mauritia flexuosa) shell flour: Nutritional composition, chemical profile, and antioxidant potential as a strategy for valuing waste from native Brazilian fruits

The Cerrado is one of the most biodiverse biomes in the world, characterized by a wealth of native fruits with unique nutritional characteristics. In this sense, the social, economic, and environmental importance of fully utilizing food is widely recognized. Therefore, generally considered waste, fruit shells can be transformed into a coproduct with high added value. The objective of this work was to carry out a comprehensive assessment of the physicochemical properties, carbohydrate and fatty acid profile, phytochemical compounds, phenolic profile, and antioxidant potential of the recovered extracts of buriti (Mauritia flexuosa) shells in natura and dehydrated at 55 °C (flour). In addition, the functional properties were verified by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) from buriti shell flour. The results indicated high fiber content and energy value for the sample processed at 55 °C (58.95 g/100 g and 378.91 kcal/100 g, respectively) and low lipid and protein content (1.03 g/100 g and 1.39 g/100 g, respectively). Regardless of the sample analyzed, maltose was the majority sugar (37.33 - 281.01 g/100 g). The main fatty acids detected were oleic acid (61.33 - 62.08 %) followed by palmitic acid (33.91 - 34.40 %). The analysis of the mineral profile demonstrated that the samples did not differ significantly from each other, showing that the drying process did not interfere with the results obtained (p ≤ 0.05). The analysis of individual phenolics allowed the identification of six phenolic compounds in buriti shells. However, it is possible to observe that the drying method had a positive and significant influence on the phenolic profile (p ≤ 0.05), with chlorogenic acid (2.63 - 8.27 mg/100 g) and trigonelline (1.06 - 41.52 mg/100 g), the majority compounds. On the other hand, it is important to highlight that buriti shells have a high content of carotenoids, mainly β-carotene (27.18 - 62.94 µg/100 g) and α-carotene (18.23 - 60.28 µg/100 g), also being positively influenced by the drying process at 55 °C (p ≤ 0.05). The dried shells showed a high content of phytochemical compounds and high antioxidant activity based on the different methods tested. The results show that buriti shell flour can be fully utilized and has nutritional and chemical aspects that can be applied to develop new sustainable, nutritious, and functional food formulations.

Octanoic acid mitigates busulfan-induced blood-testis barrier damage by alleviating oxidative stress and autophagy

BACKGROUND

The management of male infertility continues to encounter an array of challenges and constraints, necessitating an in-depth exploration of novel therapeutic targets to enhance its efficacy. As an eight-carbon medium-chain fatty acid, octanoic acid (OCA) shows promise for improving health, yet its impact on spermatogenesis remains inadequately researched.

METHODS

Mass spectrometry was performed to determine the fatty acid content and screen for a pivotal lipid component in the serum of patients with severe spermatogenesis disorders. The sperm quality was examined, and histopathological analysis and biotin tracer tests were performed to assess spermatogenesis function and the integrity of the blood-testis barrier (BTB) in vivo. Cell-based in vitro experiments were carried out to investigate the effects of OCA administration on Sertoli cell dysfunction. This research aimed to elucidate the mechanism by which OCA may influence the function of Sertoli cells.

RESULTS

A pronounced reduction in OCA content was observed in the serum of patients with severe spermatogenesis disorders, indicating that OCA deficiency is related to spermatogenic disorders. The protective effect of OCA on reproduction was tested in a mouse model of spermatogenic disorder induced by busulfan at a dose 30 mg/kg body weight (BW). The mice in the study were separated into distinct groups and administered varying amounts of OCA, specifically at doses of 32, 64, 128, and 256 mg/kg BW. After evaluating sperm parameters, the most effective dose was determined to be 32 mg/kg BW. In vivo experiments showed that treatment with OCA significantly improved sperm quality, testicular histopathology and BTB integrity, which were damaged by busulfan. Moreover, OCA intervention reduced busulfan-induced oxidative stress and autophagy in mouse testes. In vitro, OCA pretreatment (100 µM) significantly ameliorated Sertoli cell dysfunction by alleviating busulfan (800 µM)-induced oxidative stress and autophagy. Moreover, rapamycin (5 µM)-induced autophagy led to Sertoli cell barrier dysfunction, while OCA administration exerted a protective effect by alleviating autophagy.

CONCLUSIONS

This study demonstrated that OCA administration suppressed oxidative stress and autophagy to alleviate busulfan-induced BTB damage. These findings provide a deeper understanding of the toxicology of busulfan and a promising avenue for the development of novel OCA-based therapies for male infertility.

Adverse effects and potential mechanisms of polystyrene microplastics (PS-MPs) on the blood-testis barrier

Microplastics (MPs) are defined as plastic particles or fragments with a diameter of less than 5 mm. These particles have been identified as causing male reproductive toxicity, although the precise mechanism behind this association is yet to be fully understood. Recent research has found that exposure to polystyrene microplastics (PS-MPs) can disrupt spermatogenesis by impacting the integrity of the blood-testis barrier (BTB), a formidable barrier within mammalian blood tissues. The BTB safeguards germ cells from harmful substances and infiltration by immune cells. However, the disruption of the BTB leads to the entry of environmental pollutants and immune cells into the seminiferous tubules, resulting in adverse reproductive effects. Additionally, PS-MPs induce reproductive damage by generating oxidative stress, inflammation, autophagy, and alterations in the composition of intestinal flora. Despite these findings, the precise mechanism by which PS-MPs disrupt the BTB remains inconclusive, necessitating further investigation into the underlying processes. This review aims to enhance our understanding of the pernicious effects of PS-MP exposure on the BTB and explore potential mechanisms to offer novel perspectives on BTB damage caused by PS-MPs.

Tris(2-ethylhexyl) phosphate induces cytotoxicity in TM3 Leydig cells by modulating autophagy and endoplasmic reticulum stress

Tris (2-ethylhexyl) phosphate (TEHP) is a frequently used organophosphorus flame retardant with significant ecotoxicity and widespread human exposure. Recent research indicates that TEHP has reproductive toxicity. However, the precise cell mechanism is not enough understood. Here, by using testicular mesenchymal stromal TM3 cells as a model, we reveal that TEHP induces apoptosis. Then RNA sequencing analysis, immunofluorescence, and western blotting results show that THEP inhibits autophagy flux and enhances endoplasmic reticulum (ER) stress. Moreover, the activation of the ER stress is critical for TEHP-induced cell injury. Interestingly, TEHP-induced ER stress is contributed to autophagic flux inhibition. Furthermore, pharmacological inhibition of autophagy aggravates, and activation of autophagy attenuates TEHP-induced apoptosis. In summary, these findings indicate that TEHP triggers apoptosis in mouse TM3 cells through ER stress activation and autophagy flux inhibition, offering a new perspective on the mechanisms underlying TEHP-induced interstitial cytotoxicity in the mouse testis.

Dietary palm oil enhances Sterol regulatory element-binding protein 2-mediated cholesterol biosynthesis through inducing endoplasmic reticulum stress in muscle of large yellow croaker (Larimichthys crocea)

Sterol regulatory element-binding protein 2 (SREBP2) is considered to be a major regulator to control cholesterol homoeostasis in mammals. However, the role of SREBP2 in teleost remains poorly understand. Here, we explored the molecular characterisation of SREBP2 and identified SREBP2 as a key modulator for 3-hydroxy-3-methylglutaryl-coenzyme A reductase and 7-dehydrocholesterol reductase, which were rate-limiting enzymes of cholesterol biosynthesis. Moreover, dietary palm oil in vivo or palmitic acid (PA) treatment in vitro elevated cholesterol content through triggering SREBP2-mediated cholesterol biosynthesis in large yellow croaker. Furthermore, our results also found that PA-induced activation of SREBP2 was dependent on the stimulating of endoplasmic reticulum stress (ERS) in croaker myocytes and inhibition of ERS by 4-Phenylbutyric acid alleviated PA-induced SREBP2 activation and cholesterol biosynthesis. In summary, our findings reveal a novel insight for understanding the role of SREBP2 in the regulation of cholesterol metabolism in fish and may deepen the link between dietary fatty acid and cholesterol biosynthesis.

Omega-3 polyunsaturated fatty acids and its metabolite 12-HEPE rescue busulfan disrupted spermatogenesis via target to GPR120

Busulfan is an antineoplastic, which is always accompanied with the abnormal of spermatogonia self-renewal and differentiation. It has been demonstrated that the omega-3 polyunsaturated fatty acids (PUFAs) benefits mature spermatozoa. However, whether omega-3 can protect endogenous spermatogonia and the detailed mechanisms are still unclear. Evaluate of spermatogenesis function (in vivo) were examined by histopathological analysis, immunofluorescence staining, and western blotting. The levels of lipid metabolites in testicular tissue were determined via liquid chromatography. We investigated the effect of lipid metabolites on Sertoli cells provided paracrine factors to regulate spermatogonia proliferation and differentiation using co-culture system. In our study, we showed that omega-3 PUFAs significantly improved the process of sperm production and elevated the quantity of both undifferentiated Lin28+ spermatogonia and differentiated c-kit+ spermatogonia in a mouse model where spermatogenic function was disrupted by busulfan. Mass spectrometry revealed an increase in the levels of several omega-3 metabolites in the testes of mice fed with omega-3 PUFAs. The eicosapentaenoic acid metabolite 12-hydroxyeicosapentaenoic acid (12-HEPE) up-regulated bone morphogenic protein 4 (BMP4) expression through GPR120-ERK1/2 pathway activation in Sertoli cells and restored spermatogonia proliferation and differentiation. Our study provides evidence that omega-3 PUFAs metabolite 12-HEPE effectively protects spermatogonia and reveals that GPR120 might be a tractable pharmacological target for fertility in men received chemotherapy or severe spermatogenesis dysfunction.

ZDHHC5-mediated NLRP3 palmitoylation promotes NLRP3-NEK7 interaction and inflammasome activation

The nucleotide-binding domain (NBD), leucine-rich repeat (LRR), and pyrin domain (PYD)-containing protein 3 (NLRP3) inflammasome is a critical mediator of the innate immune response. How NLRP3 responds to stimuli and initiates the assembly of the NLRP3 inflammasome is not fully understood. Here, we found that a cellular metabolite, palmitate, facilitates NLRP3 activation by enhancing its S-palmitoylation, in synergy with lipopolysaccharide stimulation. NLRP3 is post-translationally palmitoylated by zinc-finger and aspartate-histidine-histidine-cysteine 5 (ZDHHC5) at the LRR domain, which promotes NLRP3 inflammasome assembly and activation. Silencing ZDHHC5 blocks NLRP3 oligomerization, NLRP3-NEK7 interaction, and formation of large intracellular ASC aggregates, leading to abrogation of caspase-1 activation, IL-1β/18 release, and GSDMD cleavage, both in human cells and in mice. ABHD17A depalmitoylates NLRP3, and one human-heritable disease-associated mutation in NLRP3 was found to be associated with defective ABHD17A binding and hyper-palmitoylation. Furthermore, Zdhhc5-/- mice showed defective NLRP3 inflammasome activation in vivo. Taken together, our data reveal an endogenous mechanism of inflammasome assembly and activation and suggest NLRP3 palmitoylation as a potential target for the treatment of NLRP3 inflammasome-driven diseases.

ZDHHC17 participates in the pathogenesis of polycystic ovary syndrome by affecting androgen conversion to estrogen in granulosa cells

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder affecting women of reproductive age and is a significant cause of female subfertility. Our previous research demonstrated that the abnormal palmitoylation of heat shock protein-90α (HSP90α) plays a role in the development of PCOS. However, the palmitoyl acyltransferases in HSP90α palmitoylation remain poorly understood. Herein, we identified ZDHHC17 as a major palmitoyl acyltransferase for HSP90α palmitoylation in granulosa cells. ZDHHC17 protein expression was diminished under excess androgen conditions in vitro and in vivo. Consistently, ovarian ZDHHC17 expression was found to be attenuated in patients with PCOS. ZDHHC17 depletion decreased HSP90α palmitoylation levels and hampered the conversion of androgen to estrogen via CYP19A1. Furthermore, ZDHHC17-mediated regulation of CYP19A1 expression was dependent on HSP90α palmitoylation. Our findings reveal that the regulatory role of HSP90α palmitoylation by ZDHHC17 is critical in PCOS pathophysiology and provide insights into the role of ZDHHC17 in reproductive endocrinology.

Protein posttranslational modifications in health and diseases: Functions, regulatory mechanisms, and therapeutic implications

Protein posttranslational modifications (PTMs) refer to the breaking or generation of covalent bonds on the backbones or amino acid side chains of proteins and expand the diversity of proteins, which provides the basis for the emergence of organismal complexity. To date, more than 650 types of protein modifications, such as the most well-known phosphorylation, ubiquitination, glycosylation, methylation, SUMOylation, short-chain and long-chain acylation modifications, redox modifications, and irreversible modifications, have been described, and the inventory is still increasing. By changing the protein conformation, localization, activity, stability, charges, and interactions with other biomolecules, PTMs ultimately alter the phenotypes and biological processes of cells. The homeostasis of protein modifications is important to human health. Abnormal PTMs may cause changes in protein properties and loss of protein functions, which are closely related to the occurrence and development of various diseases. In this review, we systematically introduce the characteristics, regulatory mechanisms, and functions of various PTMs in health and diseases. In addition, the therapeutic prospects in various diseases by targeting PTMs and associated regulatory enzymes are also summarized. This work will deepen the understanding of protein modifications in health and diseases and promote the discovery of diagnostic and prognostic markers and drug targets for diseases.

Docosahexaenoic Acid Alters Lipid Metabolism Processes via H3K9ac Epigenetic Modification in Dairy Goat

Goat milk is increasingly recognized by consumers due to its high nutritional value, richness in short- and medium-chain fatty acids, and richness in polyunsaturated fatty acids (PUFA). Exogenous supplementation of docosahexaenoic acid (DHA) is an important approach to increasing the content of PUFA in goat milk. Several studies have reported benefits of dietary DHA in terms of human health, including potential against chronic diseases and tumors. However, the mechanisms whereby an increased supply of DHA regulates mammary cell function is unknown. In this study, we investigated the effect of DHA on lipid metabolism processes in goat mammary epithelial cells (GMEC) and the function of H3K9ac epigenetic modifications in this process. Supplementation of DHA promoted lipid droplet accumulation increased the DHA content and altered fatty acid composition in GMEC. Lipid metabolism processes were altered by DHA supplementation through transcriptional programs in GMEC. ChIP-seq analysis revealed that DHA induced genome-wide H3K9ac epigenetic changes in GMEC. Multiomics analyses (H3K9ac genome-wide screening and RNA-seq) revealed that DHA-induced expression of lipid metabolism genes (FASN, SCD1, FADS1, FADS2, LPIN1, DGAT1, MBOAT2), which were closely related with changes in lipid metabolism processes and fatty acid profiles, were regulated by modification of H3K9ac. In particular, DHA increased the enrichment of H3K9ac in the promoter region of PDK4 and promoted its transcription, while PDK4 inhibited lipid synthesis and activated AMPK signaling in GMEC. The activation of the expression of fatty acid metabolism-related genes FASN, FADS2, and SCD1 and their upstream transcription factor SREBP1 by the AMPK inhibitor was attenuated in PDK4-overexpressing GMEC. In conclusion, DHA alters lipid metabolism processes via H3K9ac modifications and the PDK4-AMPK-SREBP1 signaling axis in goat mammary epithelial cells, providing new insights into the mechanism through which DHA affects mammary cell function and regulates milk fat metabolism.

Effects of n-3 PUFA supplementation on oocyte in vitro maturation in mice with polycystic ovary syndrome

n-3 PUFAs are classic antioxidant that can be used to treat follicular dysplasia and hyperinsulinemia caused by excessive oxidative stress in PCOS women. To investigate the effect of n-3 PUFA supplementation on the oocyte quality of polycystic ovary syndrome (PCOS) mice during in vitro maturation, a PCOS mouse model was established by dehydroepiandrosterone (DHEA). The GV oocytes of the control and PCOS groups were collected and cultured in vitro with or without n-3 PUFAs. After 14 h, the oocytes were collected. Our data demonstrated that the oocyte maturation rate of PCOS mice significantly increased after the addition of 50 µM n-3 PUFAs. The results of immunofluorescence showed that the abnormal rates of spindles and chromosomes in the PCOS + n-3 PUFA group were lower than those in the PCOS group. The mRNA expression of an antioxidant-related gene (Sirt1) and DNA damage repair genes (Brca1/Msh2) was found to be significantly rescued after n-3 treatment. Additionally, the results of living cell staining showed that the addition of n-3 PUFAs could reduce the levels of reactive oxygen species and mitochondrial superoxide in PCOS oocytes. In conclusion, the addition of 50 µM n-3 PUFAs during the in vitro maturation of PCOS mouse oocytes can improve the maturation rate by reducing the level of oxidative stress and the rate of spindle/chromosome abnormalities, providing valuable support during the IVM process.

PPT1 regulation of HSP90α depalmitoylation participates in the pathogenesis of hyperandrogenism

Ovarian granulosa cells (GCs) in the follicle are the important mediator of steroidogenesis and foster oocyte maturation. Evidences suggested that the function of GCs could be regulated by S-palmitoylation. However, the role of S-palmitoylation of GCs in ovarian hyperandrogenism remains elusive. Here, we demonstrated that the protein from GCs in ovarian hyperandrogenism phenotype mouse group exhibits lower palmitoylation level compared with that in the control group. Using S-palmitoylation-enriched quantitative proteomics, we identified heat shock protein isoform α (HSP90α) with lower S-palmitoylation levels in ovarian hyperandrogenism phenotype group. Mechanistically, S-palmitoylation of HSP90α modulates the conversion of androgen to estrogens via the androgen receptor (AR) signalling pathway, and its level is regulated by PPT1. Targeting AR signaling by using dipyridamole attenuated ovarian hyperandrogenism symptoms. Our data help elucidate ovarian hyperandrogenism from perspective of protein modification and provide new evidence showing that HSP90α S-palmitoylation modification might be a potential pharmacological target for ovarian hyperandrogenism treatment.

TEAD4 is a master regulator of high-risk nasopharyngeal carcinoma

The molecular basis underlying nasopharyngeal carcinoma (NPC) remains unclear. Recent progress in transcriptional regulatory network analysis helps identify the master regulator (MR) proteins that transcriptionally define malignant tumor phenotypes. Here, we investigated transcription factor-target interactions and identified TEA domain transcription factor 4 (TEAD4) as an MR of high-risk NPC. Precisely, TEAD4 promoted NPC migration, invasion and cisplatin resistance, depending on its autopalmitoylation. Mechanistically, YTHDF2 (YTH domain family 2) recognized WTAP (Wilms tumor 1-associating protein)-mediated TEAD4 m⁶A methylation to facilitate its stability and led to aberrant up-regulation of TEAD4. Up-regulated TEAD4 further drove NPC progression by transcriptionally activating BZW2 (basic leucine zipper and W2 domains 2) to induce the oncogenic AKT pathway. Moreover, the transcriptional activity of TEAD4 was independent of its canonical coactivators YAP/TAZ. Clinically, TEAD4 serves as an independent predictor of unfavorable prognosis and cisplatin response in NPC. Our data revealed the crucial role of TEAD4 in driving tumor malignancy, thus, may provide therapeutic vulnerability in NPC.

Atlas of metabolism reveals palmitic acid results in mitochondrial dysfunction and cell apoptosis by inhibiting fatty acid β-oxidation in Sertoli cells

In recent years, the impact of lipotoxicity on male fertility has received extensive attention, especially on Sertoli cells (SCs). In SCs, energy metabolism is important as disorders of energy metabolism result in infertility eventually. However, the underlying mechanism of lipotoxicity on energy metabolism in SCs remains unknown. Advances in high-throughput metabolomics and lipidomics measurement platforms provide powerful tools to gain insights into complex biological systems. Here, we aimed to explore the potential molecular mechanisms of palmitic acid (PA) regulating energy metabolism in SCs based on metabolomics and lipidomics. The results showed that glucose metabolism-related metabolites were not significantly changed, which suggested that PA treatment had little effect on glucose metabolism and may not influence the normal energy supply from SCs to germ cells. However, fatty acid β-oxidation was inhibited according to accumulation of medium- and long-chain acylcarnitines in cells. In addition, the pool of amino acids and the levels of most individual amino acids involved in the tricarboxylic acid (TCA) cycle were not changed after PA treatment in SCs. Moreover, PA treatment of SCs significantly altered the lipidome, including significant decreases in cardiolipin and glycolipids as well as remarkable increases in ceramide and lysophospholipids, which indicated that mitochondrial function was affected and apoptosis was triggered. The increased apoptosis rate of SCs was verified by elevated protein expression levels of Cleaved Caspase-3 and Bax as well as decreased Bcl-2 protein expression level. Together, these findings indicated that PA may result in mitochondrial dysfunction and increased apoptosis by inhibiting fatty acid β-oxidation of SCs.