Functions and mechanisms of non-histone protein acetylation. Nat Rev Mol Cell Biol. 2019;20:156-174. [PMID: 30467427 DOI: 10.1038/s41580-018-0081-3]

HDAC9-mediated deacetylation of CALML6 promotes excessive proliferation of glomerular mesangial cells in IgA nephropathy

PURPOSE

This study seeks to investigate the fundamental molecular processes through which histone deacetylase 9 (HDAC9) governs the proliferation of glomerular mesangial cells in the context of immunoglobulin A nephropathy (IgAN) and to identify novel targets for clinical research on IgAN.

METHODS

Data from high-throughput RNA sequencing for IgAN were procured from the Gene Expression Omnibus database to assess the expression profiles and clinical diagnostic significance of histone deacetylase family proteins (HDACs). Blood samples from 20 IgAN patients were employed in RT-qPCR analysis, and the spearman linear regression method was utilized to analyze the clinical correlation. The proliferation of glomerular mesangial cells (GMCs) under the influence of HDAC9 was examined using the 5-ethynyl-2'-deoxyuridine (EdU) assay. Proteins interacting with HDAC9 were predicted utilizing the STRING database. Immunoprecipitation and protein immunoblotting employing anti-acetylated lysine antibodies were conducted to determine the acetylation status of calmodulin-like protein 6 (CALML6).

RESULTS

Analysis of the GSE141295 dataset revealed a significant upregulation of HDAC9 expression in IgAN and the results of RT-qPCR demonstrated a substantial increase in HDAC9 expression in IgAN patients. Receiver operating characteristic (ROC) analysis indicated that the area under the curve (AUC) value for HDAC9 were 0.845 and Spearman correlation analysis showed that HDAC9 expression was positively correlated with blood levels of blood urea nitrogen (BUN) and serum creatinine (Crea). The EdU cell proliferation assay indicated that HDAC9 facilitated the excessive proliferation of GMCs. The STRING database and recovery experiments identified CALML6 as a downstream effector of HDAC9 in controlling abnormal GMC multiplication. Co-immunoprecipitation assays demonstrated that HDAC9 modulates CALML6 expression through acetylation modification.

CONCLUSION

HDAC9 is markedly upregulated in IgAN, and it mediates the excessive proliferation of GMCs by regulating the deacetylation of CALML6.

Decoding a novel non-enzymatic protein acetylation mechanism in sperm that is essential for fertilizing potential

BACKGROUND

Protein acetylation has emerged as essential for sperm function, attracting considerable attention recently. Acetylation, typically mediated by lysine acetyltransferases, involves attaching an acetyl group from acetyl-coenzyme A to lysine residues in proteins. Under alkaline conditions, however, acetylation can occur with minimal enzymatic involvement, primarily due to an elevated pH. As sperm migrate towards the ampulla, they experience increasing intracellular pH (pHi) while undergoing two crucial processes for fertilization: capacitation and the acrosome reaction (AR). Whereas the involvement of acetylating enzymes in these events has been partially investigated, the potential for non-enzymatic acetylation driven by the pHi alkalinization remains unknown.

RESULTS

This study examined protein acetylation (acLys) levels in sperm incubated under capacitating conditions at pH 7.2 and pH 9.0, the latter condition potentially promoting non-enzymatic acetylation. To more precisely investigate the occurrence of non-enzymatic acetylation events, acetyltransferase activity was selectively attenuated using a specific cocktail of inhibitors. The functional implications of these conditions were assessed by examining key fertilization-related sperm attributes, including motility during capacitation and the ability to initiate the AR. Results demonstrated that alkaline conditions elevated basal acLys levels even with reduced acetyltransferase activity (P < 0.05), indicative of non-enzymatic acetylation. α-tubulin, particularly in the midpiece of the sperm flagellum, was identified as a specific target of this modification, correlating with diminished motility during capacitation. Following the AR, acLys levels in the head and midpiece decreased (P < 0.05) under conditions promoting non-enzymatic acetylation, accompanied by reductions in intracellular and acrosomal pH. In contrast, acLys levels and pH in the sperm head incubated under standard capacitating conditions (pH 7.2) remained stable. Sperm exposed to conditions conducive to non-enzymatic acetylation exhibited an impaired ability to trigger the AR (P < 0.05) compared to those maintained at pH 7.2. Notably, diminished acetylase activity emerged as a key factor impairing the maintenance of intracellular and acrosomal pH levels attained during capacitation, even under a pH of 9.0.

CONCLUSION

This study provides novel evidence for the occurrence of non-enzymatic acetylation in sperm, linked to the modulation of α-tubulin acetylation levels and motility during capacitation. Additionally, it suggests that acetyltransferase activity may play a crucial role in regulating intracellular and acrosomal pH levels in capacitated sperm, facilitating the AR.

Acetylation-induced degradation of ECHS1 enhances BCAA accumulation and proliferation in KRAS-mutant colorectal cancer

BACKGROUND

Branched-chain amino acid (BCAA) metabolism is dysregulated in colorectal cancer (CRC), with elevated plasma BCAA levels significantly associated with an increased risk of developing the disease. However, whether BCAAs directly promote CRC progression and their underlying mechanisms remain unclear.

METHODS

In this study, we investigated the metabolic alterations in KRAS-mutant CRC. We examined the effects of restricting BCAA supply on the proliferation and metastasis of KRAS-mutant CRC cells both in vitro and in vivo.

RESULTS

We found that in KRAS-mutant CRC, BCAAs and their metabolic products accumulate markedly. Restricting the BCAA supply specifically inhibits the proliferation of KRAS-mutant CRC cells but does not affect metastasis. In these cancer cells, enoyl-CoA hydratase-1 (ECHS1), a key enzyme in BCAA metabolism, is downregulated. Furthermore, BCAAs enhance the acetylation of lysine 204 on ECHS1, impairing its ability to bind enoyl-CoA and reducing its catalytic activity. This modification triggers the ubiquitination of ECHS1 and its subsequent degradation, diminishing BCAA catabolism and leading to its cellular accumulation. This accumulation activates the mTORC1 signaling pathway, which induces the transcriptional activation of downstream target proteins and promotes the malignant progression of CRC.

CONCLUSIONS

Limiting BCAA intake not only suppresses tumor growth in KRAS-mutant CRC but also enhances the efficacy of the KRAS G12D inhibitor MRTX1133 and the monoclonal antibody bevacizumab. Our findings reveal a previously unknown regulatory mechanism of ECHS1 in CRC and offer new potential therapeutic targets.

P5CS deacetylation mediated by SIRT2 facilitates tumor growth by enhancing mitochondrial respiration in hepatocellular carcinoma

Cancer cells typically exhibit enhanced mitochondrial metabolism to fulfill their energy and biosynthetic demands for growth. The mitochondrial response to fluctuations in cellular energy demand is essential for cellular adaptation and proper organ function. The mitochondrial delta-1-pyrroline-5-carboxylate synthase (P5CS) encoded by the ALDH18A1 gene, the key enzyme for proline synthesis, is frequently up-regulated during tumor development. However, the regulatory mechanisms governing P5CS activity in the occurrence and development of hepatocellular carcinoma (HCC) remain largely unknown. In this study, we observe that P5CS is highly expressed in HCC tissues, and elevated levels of P5CS expression are associated with poor prognosis in HCC patients. Notably, the knockdown of P5CS inhibits the proliferation, migratory and invasive capabilities of HCC cells by reducing mitochondrial respiration. Furthermore, we demonstrate that SIRT2 interacts with P5CS and mediates the deacetylation of P5CS at lysines K311 and K347, thereby activating its enzymatic activity. Activated P5CS significantly enhances mitochondrial respiration, which supports the proliferation and tumorigenesis of HCC cells. In addition, SIRT2 knockdown inhibits the proliferation, migratory and invasive capabilities of HCC cells. These observations suggest that SIRT2-mediated P5CS deacetylation is a crucial signaling event through which cancer cells sustain mitochondrial respiration and promote HCC progression. This finding offers the potential for targeting SIRT2-mediated P5CS deacetylation as a therapeutic strategy for HCC.

Global Analysis of the Lysine Acetylome in Macrophages from Salt-sensitive Hypertensive Rats

Research indicates that patients with salt-sensitive (SS) hypertension experience higher morbidity and target organ damage than in patients with non-SS hypertension. Dysregulated macrophage activation has been implicated in SS hypertension development, with lysine acetylation playing a role in modulating macrophage function. However, the role of macrophage acetylation patterns in SS hypertension remains unclear. This study aimed to investigate how acetylation regulates macrophage function and its role in the pathogenesis of SS hypertension. We employed quantitative acetylation proteomics to characterize the acetylome of bone marrow-derived macrophages in Dahl SS hypertensive rats fed either a high-salt or a low-salt diet. We identified 94 hyperacetylated and 49 hypoacetylated sites on 79 and 45 proteins, respectively, in the high-salt group. Notably, acetylation levels increased at lysine 20 (K20) and K46 on histone H2B, at K56 on H3, and at K77 and K79 on H4c2. We also identified conserved acetylation motifs, analyzed their Gene Ontology terms and pathways, and explored the protein-protein interactions of these differentially acetylated proteins using bioinformatics analyses. Finally, we validated the altered acetylation of H2, H3, H4, and several metabolic proteins using immunoprecipitation and western blotting. Overall, these findings offer insights into the role of lysine acetylation in macrophages from SS hypertensive rats, revealing potential therapeutic targets.

Fucosylation of hemocyanin is critical for antibacterial immunity in Penaeus vannamei

Posttranslational modifications (PTMs) play a pivotal role in expanding the function of immune related proteins, especially during pathogen infections. However, the precise impact of PTMs on the functional diversity of proteins such as respiratory glycoproteins and hemocyanins remains incompletely understood. In this study, we investigated the fucosylation modification of Penaeus vannamei hemocyanin (PvHMC) and its impact on antibacterial immunity. Our findings reveal that PvHMC underwent fucosylation, mediated by Penaeus vannamei fucosyltransferase 8/10 (PvFUT8/10), which enhances its antibacterial immunity and binding ability against Gram-negative bacteria. Conversely, defucosylation of PvHMC, catalyzed by Penaeus vannamei fucosidase (PvAFU) weakens its antibacterial activity in vitro. These results highlight the regulatory role of fucosylation in modulating the antibacterial function of PvHMC in shrimp.

Exercise intensity determines circulating levels of Lac-Phe and other exerkines: a randomized crossover trial

INTRODUCTION

Exercise metabolomics research has revealed significant exercise-induced metabolic changes and identified several exerkines as mediators of physiological adaptations to exercise. However, the effect of exercise intensity on metabolic changes and circulating exerkine levels remains to be examined.

OBJECTIVES

This study compared the metabolic responses to moderate-intensity and vigorous-intensity aerobic exercise.

METHODS

A two-period crossover trial was conducted under controlled conditions at the Max Rubner-Institute in Karlsruhe, Germany. Seventeen young, healthy, and physically active men performed 30 min moderate-intensity (50% VO2peak) and vigorous-intensity (75% VO2peak) aerobic exercise using two bicycle ergometer protocols in a randomized sequence. Blood samples obtained immediately before exercise and at four time points after exercise were analyzed in an untargeted metabolomics approach, and separate linear mixed models were applied to over 1000 metabolites.

RESULTS

Vigorous-intensity exercise induced a greater metabolic response than moderate-intensity exercise. Several intensity-dependent metabolites were identified, primarily involved in amino acid metabolism and energy conversion pathways, including N-lactoyl-amino acids, TCA cycle intermediates, N-acetylated amino acids, and acylcholines. The exerkines N-lactoyl-phenylalanine, lactate, and succinate were among the most intensity-dependent metabolites. N-acetylated amino acids and acylcholines were systematically altered by exercise intensity, indicating potential physiological functions.

CONCLUSION

Exercise intensity significantly affects exercise-induced metabolic alterations and changes in exerkine levels. Our results expand the knowledge about exerkine dynamics and emphasize the role of exercise intensity in promoting physiological adaptations to exercise. The trial was registered on October 5, 2017, at the German Clinical Trials Register under the Registration Number DRKS00009743 (Universal Trial Number of WHO: U1111-1200-2530).

Potential role of lysine acetylation in the stepwise adaptation of Candida albicans to fluconazole

Candida albicans is an opportunistic fungal pathogen capable of causing superficial mucosal and systemic infections, sometimes leading to life-threatening conditions. The increasing resistance of C. albicans to azole antifungals has become a significant challenge in clinical treatment. Lysine acetylation (KAc) is a well-studied post-translational modification that plays crucial roles in various biological processes. However, its impact on antifungal resistance in C. albicans remains poorly understood. Five strains of C. albicans isolated from the same patient, representing different stages of acquired fluconazole resistance in vivo, were used in this study to investigate the potential regulatory mechanism of KAc on the development of azole resistance in C. albicans. Quantitative proteomic analysis using tandem mass tag (TMT) labeling, acetylation enrichment, and liquid chromatography-mass spectrometry (LC-MS) was conducted on these five strains. We divided all strains into four comparison groups and identified a total of 1,796 lysine acetylation sites across 938 proteins, with quantitative data available for 1,314 acetylation sites in 712 proteins. Analysis of 155 significantly differentially modified sites revealed that the acetylation levels of key proteins involved in the conversion of pyruvate to acetyl-CoA for entry into the tricarboxylic acid (TCA) cycle for energy production were initially decreased and then increased during the acquisition of fluconazole resistance. Additionally, the acetylation levels of proteins involved in ribosome synthesis, translation processes, and amino acid synthesis were found to increase. Therefore, lysine acetylation in C. albicans may contribute to azole resistance by regulating energy metabolism and protein synthesis.

I

Candida albicans, an opportunistic fungal pathogen, presents significant clinical challenges due to its escalating resistance to azole antifungals, especially fluconazole. This study investigates the role of lysine acetylation in the development of azole resistance using multiple strains isolated from a single patient with varying resistance levels. Through advanced proteomic analysis, we identified numerous lysine acetylation sites on proteins involved in key metabolic pathways. The results revealed a dynamic change in the acetylation of proteins related to energy metabolism - specifically, those connecting pyruvate to the tricarboxylic acid cycle-which correlated with the evolution of resistance. Additionally, increased acetylation was observed in proteins linked to ribosome synthesis and translation processes. These findings suggest that lysine acetylation is crucial for regulating metabolic and protein synthesis pathways, potentially influencing azole resistance in C. albicans.

Deacetylation of ANXA2 by SIRT2 desensitizes hepatocellular carcinoma cells to donafenib via promoting protective autophagy

Hepatocellular carcinoma (HCC) is one of the most lethal forms of cancer globally. HCC cells frequently undergo macroautophagy, also known as autophagy, which can lead to tumor progression and chemotherapy resistance. Annexin A2 (ANXA2) has been identified as a potential therapeutic target in HCC and is involved in the regulation of autophagic process. Here, we for the first time showed that ANXA2 deacetylation plays a crucial role in donafenib-induced autophagy. Mechanistically, donafenib increased SIRT2 activity via triggering both SIRT2 dephosphorylation and deacetylation by respectively downregulating cyclin E/CDK and p300. Moreover, elevation of SIRT2 activity by donafenib caused ANXA2 deacetylation at K81/K206 sites, leading to a reduction of the binding between ANXA2 and mTOR, which resulted in a decrease of mTOR phosphorylation and activity, and ultimately promoted protective autophagy and donafenib insensitivity in HCC cells. Additionally, ANXA2 deacetylation at K81/K206 sites was positively correlated with poor prognosis in HCC patients. Meanwhile, we found that selective inhibition of SIRT2 increased the sensitivity of donafenib in HCC cells by strengthening ANXA2 acetylation. In summary, this study reveals that donafenib induces protective autophagy and decreases its sensitivity in HCC cells through enhancing SIRT2-mediated ANXA2 deacetylation, which suggest that targeting ANXA2 acetylation/deacetylation may be a promising strategy for improving the sensitivity of donafenib in HCC treatment.

Role of lysine lactylation in neoplastic and inflammatory pulmonary diseases (Review)

Protein lysine lactylation is a ubiquitous and post‑translational modification of lysine residues that involves the addition of a lactyl group on both histone and non‑histone proteins. This process plays a pivotal role in human health and disease and was first discovered in 2019. This epigenetic modification regulates gene transcription from chromatin or directly influences non‑histone proteins by modulating protein‑DNA/protein interactions, activity and stability. The dual functions of lactylation in both histone and non‑histone proteins establish it as a crucial mechanism involved in various cellular processes, such as cell proliferation, differentiation, immune and inflammatory responses and metabolism. Specific enzymes, referred to as 'writers' and 'erasers', catalyze the addition or removal of lactyl groups at designated lysine sites, thereby dynamically modulating lactylation through alterations in their enzymatic activities. The respiratory system has a remarkably intricate metabolic profile. Numerous pulmonary diseases feature an atypical transition towards glycolytic metabolism, which is linked to an overproduction of lactate, a possible substrate for lactylation. However, there has yet to be a comprehensive review elucidating the full impact of lactylation on the onset, progression and potential treatment of neoplastic and inflammatory pulmonary diseases. In the present review, an extensive overview of the discovery of lactylation and advancements in research on the existing lactylation sites were discussed. Furthermore, the review particularly investigated the potential roles and mechanisms of histone and non‑histone lactylation in various neoplastic and inflammatory pulmonary diseases, including non‑small cell lung cancers, malignant pleural effusion, pulmonary fibrosis, acute lung injury and asthma, to excavate the new therapeutic effects of post‑translational modification on various pulmonary diseases.

Lysine deacetylase TaSRT1 mediates wheat drought tolerance by deacetylating TaDT-A to reduce its protein stability and transcriptional activity

Drought is one of the major environmental stresses limiting crop growth and yield. Epigenetic regulations play crucial roles in plant adaptation to environmental changes, whereas the epigenetic mechanism of drought resistance in crops remains largely elusive. Here, we report that the nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase TaSRT1 negatively regulates drought tolerance in wheat. Compared with the wild type, the tasrt1 mutant had higher relative water contents, along with a smaller stomatal aperture and improved water use efficiency under drought conditions, whereas TaSRT1 overexpression plants exhibited opposite phenotypes. TaSRT1 directly interacted with the drought-resistant pivotal factor TaDT-A to regulate its protein stability and transcriptional activity through lysine deacetylation. Furthermore, the key lysine residue of TaDT-A was identified as a deacetylation/acetylation site that plays an important role in regulating its stability. In addition, genetic analysis indicated TaDT-A functions downstream of TaSRT1 to modulate drought resistance. These findings uncover how the functional interplay between epigenetic regulator and transcription factors regulates drought resistance in plants, and illustrate a mechanism by which lysine deacetylase affects gene transcription via influencing non-histone protein acetylation and regulating their function.

The essential kinase TgGSK regulates centrosome segregation and endodyogeny in Toxoplasma gondii

Intracellular replication is crucial for the success of apicomplexan parasites, including Toxoplasma gondii. Therefore, essential players in parasite replication represent potential targets for drug development. We have characterized TgGSK, a glycogen synthase kinase homolog that plays an important role in Toxoplasma endodyogeny. We have shown that TgGSK has a dynamic localization that is concurrent with the cell cycle. In non-dividing parasites, this kinase is highly concentrated in the nucleus. However, during division, TgGSK displays a cytosolic localization, with concentration foci at the centrosomes, a key organelle involved in parasite division, and the basal end. Conditional knockdown of TgGSK determined that it is essential for the completion of the lytic cycle and proper parasite division. Parasites lacking endogenous protein levels of TgGSK exhibited defects in division synchronicity and the segregation of the nucleus and apicoplast into forming daughter cells. These phenotypes are associated with defects in centrosome duplication and fission. Global phosphoproteomic analysis determined TgGSK-dependent phosphorylation of RNA-processing, basal end, and centrosome proteins. Consistent with the putative regulation of RNA-processing proteins, global transcriptomic analysis suggests that TgGSK is needed for proper splicing. Finally, we show that TgGSK interacts with GCN5b, a well-characterized acetyltransferase with roles in transcriptional control. Conversely, GCN5b chemical inhibition results in specific degradation of TgGSK. Thus, these studies reveal the involvement of TgGSK in various crucial processes, including endodyogeny and splicing, and identify acetylation as a possible mechanism by which this essential kinase is regulated.

IMPORTANCE

While infection with the parasite Toxplasma gondii is largely asymptomatic in healthy adults, severe disease and death can result in immunocompromised individuals and in those infected congenitally. With minimal treatments for toxoplasmosis available, it is crucial to study parasite-specific processes to identify new drug targets. This study investigated the protein TgGSK, uncovering its essentiality for parasite proper division and survival. We performed an in-depth study of the functional role of this kinase. Importantly, TgGSK was shown to bear higher homology to plant proteins than its mammalian counterparts, which may allow for specific targeting of this protein.

Acetylation and deacetylation dynamics in stress response to cancer and infections

In response to stress stimuli, cells have evolved various mechanisms to integrate internal and external signals to achieve dynamic homeostasis. Lysine acetyltransferase (KATs) and deacetyltransferase (KDACs) are the key modulators of epigenetic modifications, enabling cells to modulate cellular responses through the acetylation and deacetylation of both histone and nonhistone proteins. Understanding the signaling pathways involved in cellular stress response, along with the roles of KATs and KDACs may pave the way for the development of novel therapeutic strategies. This review discusses the molecular mechanisms of acetylation and deacetylation in stress responses related to tumorigenesis, viral and bacterial infections. In tumorigenesis section, we focused on the tumor cells' intrinsic and external molecules and signaling pathways regulated by acetylation and deacetylation modification. In viral and bacterial infections, we summarized the update research on acetylation and deacetylation modification in viral and bacterial infections, which systematical introduction on this topic is not too much. Additionally, we provide an overview of current therapeutic interventions and clinical trials involving KAT and KDAC inhibitors in the treatment of cancer, as well as viral and bacterial infection-related diseases.

Histone deacetylases and their inhibitors in kidney diseases

Histone deacetylases (HDACs) have emerged as key regulators in the pathogenesis of various kidney diseases. This review explores recent advancements in HDAC research, focusing on their role in kidney development and their critical involvement in the progression of chronic kidney disease (CKD), acute kidney injury (AKI), autosomal dominant polycystic kidney disease (ADPKD), and diabetic kidney disease (DKD). It also discusses the therapeutic potential of HDAC inhibitors in treating these conditions. Various HDAC inhibitors have shown promise by targeting specific HDAC isoforms and modulating a range of biological pathways. Their protective effects include modulation of apoptosis, autophagy, inflammation, and fibrosis, underscoring their broad therapeutic potential for kidney diseases. However, further research is essential to improve the selectivity of HDAC inhibitors, minimize toxicity, overcome drug resistance, and enhance their pharmacokinetic properties. This review offers insights to guide future research and prevention strategies for kidney disease management.

Acetylation of Hsc70 at K512 inhibits goat ovarian granulosa cell senescence by restoring chaperone-mediated autophagy

Nonhistone acetylation plays a crucial role in key cellular processes associated with ageing, such as autophagy. Heat shock cognate protein 70 (Hsc70), a vital chaperone protein for chaperone-mediated autophagy (CMA), exerts a molecular chaperone function that is regulated by its acetylation status. However, the effects of this acetylation on CMA and granulosa cell senescence remain unclear. This study investigated the effects of Hsc70 acetylation on CMA activity and senescence in goat ovarian granulosa cells (GCs). Notably, Hsc70 acetylation was found to mitigate granulosa cell senescence and promote CMA activity. Mass spectrometry analysis identified Hsc70 K512 as the acetylation site, and Sirtuin 2 (Sirt2) was found to catalyze the deacetylation of this site. In addition, Hsc70 expression and CMA activity were significantly reduced in ageing ovaries and under oxidative stress conditions. Subsequent experiments revealed that deacetylated Hsc70 increased the early and late apoptotic rates of GCs and inhibited CMA activity. Functionally, acetylation of the Hsc70 K512 site alleviates the ageing of GCs. In conclusion, this study elucidates the molecular mechanism through which Hsc70 K512 acetylation alleviates cell senescence by enhancing CMA activity in goat ovarian GCs, providing novel insights and potential intervention targets for female mammalian reproduction.

Acetylation suppresses breast cancer progression by sustaining CLYBL stability

BACKGROUND

The incidence of breast cancer remains high and it remains the leading cause of cancer-related deaths in women. A better understanding of the molecular mechanisms of breast cancer and identifying novel biomarkers will help improve therapeutic strategies. Citrate lyase beta like (CLYBL) is expressed at low levels in breast cancer tissues and is associated with low patient survival rates. In this study, we explored the regulatory mechanisms of CLYBL and its acetylation in breast cancer.

METHODS

CLYBL expression patterns in breast cancer were assessed using a breast cancer tissue microarray, immunohistochemistry, and publicly available datasets. The acetylation patterns of CLYBL and the related regulatory functions were detected by high resolution mass spectrometry, immunoprecipitation assays, and western blot analysis. The potential effects of CLYBL and its acetylation on breast cancer were determined using both in vitro and in vivo assays.

RESULTS

CLYBL was expressed at lower levels in breast cancer samples compared with normal tissues. This low CLYBL expression was associated with poor patient survival rates. Overexpressing CLYBL could inhibit breast cancer and reduce NRF2 pathway-mediated antioxidants. We identified two acetylated lysine sites in CLYBL, K57 and K82, using acetylated peptide affinity enrichment and high-resolution mass spectrometry. Our results suggest that K82 is the main acetylation site. Further work showed that the p300/CBP associated factor (PCAF) and histone deacetylase 3 (HDAC3) as the CLYBL acetyltransferase and deacetylase, respectively. Additionally, CLYBL acetylation facilitates its own protein stability by reducing it affinity for ubiquitin, thus enhancing the anti-breast cancer effects.

CONCLUSION

We revealed the role of CLYBL overexpression and its acetylation in breast cancer. Our study suggests that CLYBL is a potential molecular target for breast cancer therapy.

Spatial control of m6A deposition on enhancer and promoter RNAs through co-acetylation of METTL3 and H3K27 on chromatin

Interaction between the N6-methyladenosine (m6A) methyltransferase METTL3 and METTL14 is critical for METTL3 to deposit m6A on various types of RNAs. It remains to be uncovered whether there is spatial control of m6A deposition on different types of RNAs. Here, through genome-wide CRISPR-Cas9 screening in the A549 cell line, we find that H3K27ac acetylase p300-mediated METTL3 acetylation suppresses the binding of METTL3 on H3K27ac-marked chromatin by inhibiting its interaction with METTL14. Consistently, p300 catalyzing the acetylation of METTL3 specifically occurs on H3K27ac-marked chromatin. Disruptive mutations on METTL3 acetylation sites selectively promote the m6A of chromatin-associated RNAs from p300-bound enhancers and promoters marked by H3K27ac, resulting in transcription inhibition of ferroptosis-inhibition-related genes. In addition, PAK2 promotes METTL3 acetylation by phosphorylating METTL3. Inhibition of PAK2 promotes ferroptosis in a manner that depends on the acetylation of METTL3. Our study reveals a spatial-selective way to specifically regulate the deposition of m6A on enhancer and promoter RNAs.

Validation of selective catalytic BmCBP inhibitors that regulate the Bm30K-24 protein expression in silkworm, Bombyx mori

The cAMP response element binding protein (CREB)-binding protein (CBP) is a histone acetyltransferase that plays an indispensable role in regulating the acetylation of histone and non-histone proteins. Recently, it has been discovered that chemical inhibitors A485 and C646 can bind to Bombyx mori's CBP (BmCBP) and inhibit its acetyltransferase activity. Notably, the binding ability of A485 with BmCBP showed a very low Kd value of 48 nM by surface plasmon resonance (SPR) test. Further identification showed that both A485 and C646 can decrease the acetylation level of known substrate H3K27 and only 1 μM of A485 can almost completely inhibit the acetylation of H3K27, suggesting that A485 is an effective inhibitor of BmCBP's acetyltransferase activity. Moreover, it was confirmed that A485 could downregulate the expression of acetylated Bm30K-24 protein at a post-translational level through acetylation modification by BmCBP. Additionally, it was found that A485 can downregulate the stability of Bm30K-24 and improve its ubiquitination level, suggesting that the acetylation modification by BmCBP could compete with ubiquitination modification at the same lysine site on Bm30K-24, thereby affecting its protein stability. Here, we predict that A485 may be a potent CBP acetyltransferase inhibitor which could be utilized to inhibit acetyltransferase activity in insects, including silkworms.

Genetically Encoded Fluorescent and Bioluminescent Probes for HDAC8

Protein-based probes constructed via genetically encoding acetyl lysine (AcK) or its close analogs represent an important way to detect protein lysine deacetylases. Existing reported probes exhibit excellent sensitivity to NAD+-dependent sirtuins but lack responsiveness to Zn2+-dependent histone deacetylases (HDACs). Herein, we reformed the probe design by replacing the genetically encoded AcK with trifluoroacetyl lysine (TfAcK) and generated fluorescent and bioluminescent probes that could respond specifically to HDAC8 recombinantly expressed in E. coli and to endogenous HDACs in mammalian cells. We believe these probes would benefit the biological investigation of HDAC8 and promisingly some other HDACs, as well as the discovery of innovative HDAC inhibitors.

Proteomic Analysis of Marine Bacteriophages: Structural Conservation, Post-Translational Modifications, and Phage-Host Interactions

Marine bacteriophages, the most abundant biological entities in marine ecosystems, are essential in biogeochemical cycling. Despite extensive genomic data, many phage genes remain uncharacterised, creating a gap between genomic diversity and gene function knowledge. This gap limits our understanding of phage life cycles, assembly, and host interactions. In this study, we used mass spectrometry to profile the proteomes of 13 marine phages from diverse lifestyles and hosts. The analysis accurately annotated hypothetical genes, mapped virion protein arrangements, and revealed structural similarities among phages infecting the same host, particularly in tail fibre proteins. Protein structure comparisons showed conservation and variability in head and tail proteins, particularly in key domains involved in virion stabilisation and host recognition. For the first time, we identified post-translational modifications (PTMs) in marine phage proteins, which may enhance phage adaptability and help evade host immune systems. These findings suggest that phages optimise their infection strategies through structural variations and PTM modifications, improving their adaptability and host interactions.

Acetylation: a new target for protein degradation in cancer

Acetylation is an increasing area of focus for cancer research as it is closely related to a variety of cellular processes through modulation of histone and non-histone proteins. However, broadly targeting acetylation threatens to yield nonselective toxic effects owing to the vital role of acetylation in cellular function. There is thus a pressing need to elucidate and characterize the specific cancer-relevant roles of acetylation for future therapeutic design. Acetylation-mediated protein homeostasis is an example of selective acetylation that affects a myriad of proteins as well as their correlated functions. We review recent examples of acetylation-mediated protein homeostasis that have emerged as key contributors to tumorigenesis, tumor proliferation, metastasis, and/or drug resistance, and we discuss their implications for future exploration of this intriguing phenomenon.

Lysine acetylation of aquaporin-3 promotes water permeability but is not essential for urine concentrating ability

Aquaporin-3 (AQP3) mediates basolateral water transport in the kidney principal cells contributing to urine concentration. We previously identified the acetylation of lysine 282 (K282) in the C-terminus of AQP3, which we hypothesized as a positive regulator of AQP3 water permeability. AQP3 acetylation (K282Q or Q) or deacetylation (K282R or R) mimetic mutant mice models were created using CRISPR/Cas9. Male and female wild-type (WT) and mutant mice were assigned to hydrating diets and water deprivation protocols. Urine and plasma osmolality in response to acute vasopressin receptor-2 activation with desmopressin (dDAVP) or inhibition by tolvaptan were determined. In vitro water permeability of murine principal kidney cortical collecting duct (mpkCCD) cells stably expressing AQP3 WT, Q, or R was measured. Acetylated AQP3 was prominent in the cortical to inner medullary collecting ducts of dehydrated versus hydrated mice. At baseline, the mutations did not affect the kidney transcriptome, AQP3 abundance, or subcellular localization. Urine osmolality of the mutant mice was within the normal range. With dehydration, all mice excreted concentrated urine; however, the female Q mutants exhibited significantly greater 24-h urine osmolality than WT, suggesting greater water reabsorption. In response to acute dDAVP, all mice produced concentrated urine; however, female Q mutants had a more dilute plasma than WT, further suggesting greater water retention. mpkCCD Q mutant cells exhibited greater water permeability than WT and R cells. We conclude that AQP3 K282 acetylation promotes principal cell water permeability in a sex-dependent manner; however, it is not essential for urine concentration.NEW & NOTEWORTHY The water channel, AQP3, is lysine 282 acetylated (acAQP3) in rodents and humans. When dehydrated, mouse cortical to inner medullary collecting ducts express acAQP3, suggesting that it promotes water reabsorption. acAQP3 expressing principal cells have high water permeability, and in vivo acute desmopressin resulted in a dilute plasma in female acAQP3 mice. However, all mice produced concentrated urine during water deprivation. Thus, acAQP3 promotes water permeability but is not essential for urine concentration during antidiuresis.

HDAC2 promotes colorectal tumorigenesis by triggering dysregulation of lipid metabolism through YAP1

Dysfunction of lipid metabolism is important for the development and progression of colorectal cancer, but the underlying mechanisms remain unclear. Here, HDAC2 was identified as highly expressed in both adenoma and colorectal cancer. We aimed to explore the roles and mechanisms of HDAC2 in lipid metabolism in colorectal cancer. HDAC2 expression in adenoma and colorectal cancer tissues was measured using tissue arrays. The function of HDAC2/YAP1 was identified using in vitro and in vivo experiments. Coimmunoprecipitation experiments, DNA pull-down assays, luciferase analyses, and ChIP-qPCR (Chromatin Immunoprecipitation-quantitative real-time polymerase chain reaction) assays were used to identify the potential mechanisms of HDAC2. We found that HDAC2 can disrupt lipid metabolism in colorectal cancer by mediating the deacetylation of YAP1. Mechanistically, HDAC2 can bind to YAP1 and mediate deacetylation of the K280 site of YAP1. Furthermore, the deacetylation of YAP1 reduces the efficiency of its binding to the ZMYND11 promoter region, exacerbating lipid metabolism disorders, which in turn reduce lipid accumulation and increase lipid catabolism in colorectal cancer cells. Our study identified a novel regulatory mechanism of lipid metabolism in colorectal cancer in which HDAC2 increases lipid catabolism by regulating the deacetylation of the K280 site of YAP1, revealing that HDAC2 promotes tumor progression through the regulation of lipid metabolism.

MIER2/PGC1A elicits sunitinib resistance via lipid metabolism in renal cell carcinoma

INTRODUCTION

Renal cell carcinoma (RCC) is one of the most common malignant tumors of the urinary system and accounts for more than 90 % of all renal tumors. Resistance to targeted therapy has emerged as a pivotal factor that contributes to the progressive deterioration of patients with advanced RCC. Metabolic reprogramming is a hallmark of tumorigenesis and progression, with an increasing body of evidence indicating that abnormal lipid metabolism plays a crucial role in the advancement of renal clear cell carcinoma.

OBJECTIVES

Clarify the precise mechanisms underlying abnormal lipid metabolism and drug resistance.

METHODS

Bioinformatics screening and analyses were performed to identify hub gene. qRT-PCR, western blot, chromatin immunoprecipitation (ChIP) assays, and other biological methods were used to explore and verify related pathways. Various cell line models and animal models were used to perform biological functional experiments.

RESULTS

In this study, we identified Mesoderm induction early response 2 (MIER2) as a novel biomarker for RCC, demonstrating its role in promoting malignancy and sunitinib resistance by influencing lipid metabolism in RCC. Mechanistically, MIER2 facilitated P53 deacetylation by binding to HDAC1. Acetylation modification augmented the DNA-binding stability and transcriptional function of P53, while deacetylation of P53 hindered the transcriptional process of PGC1A, leading to intracellular lipid accumulation in RCC. Furthermore, Trichostatin A (TSA), an inhibitor of HDAC1, was found to impede the MIER2/HDAC1/P53/PGC1A pathway, offering potential benefits for patients with sunitinib-resistant renal cell cancer.

CONCLUSION

Our findings highlight MIER2 as a key player in anchoring HDAC1 and inhibiting PGC1A expression through the deacetylation of P53, thereby inducing lipid accumulation in RCC and promoting drug resistance. Lipid-rich RCC cells compensate for energy production and sustain their own growth in a glycolysis-independent manner, evading the cytotoxic effects of targeted drugs and ultimately culminating in the development of drug resistance.

Functions and mechanisms of non-histone post-translational modifications in cancer progression

Protein post-translational modifications (PTMs) refer to covalent and enzymatic alterations to folded or nascent proteins during or after protein biosynthesis to alter the properties and functions of proteins. PTMs are modified in a variety of types and affect almost all aspects of cell biology. PTMs have been reported to be involved in cancer progression by influencing multiple signaling pathways. The mechanism of action of histone PTMs in cancer has been extensively studied. Notably, evidence is mounting that PTMs of non-histone proteins also play a vital role in cancer progression. In this review, we provide a systematic description of main non-histone PTMs associated with cancer progression, including acetylation, lactylation, methylation, ubiquitination, phosphorylation, and SUMOylation, based on recent studies.

Targeted Degradation of Bromodomain-Containing Protein 4 Enabled by Reactive Oxygen Species-Activatable NanoPROTACs as an Efficient Strategy to Reverse Liver Fibrosis in Chronic Liver Injury

Liver fibrosis is an inadequate response to tissue stress, with reactive oxygen species (ROS) overproduction in activated hepatic stellate cells (aHSCs). Bromodomain-containing protein 4 (BRD4) was found to be upregulated in aHSCs and has been identified as an effective target for the treatment of liver fibrosis. However, inhibition of BRD4 with traditional kinase inhibitors achieved only limited success because of its low therapeutic efficiency. Furthermore, the exact mechanism by which BRD4 regulates liver fibrosis remains unclear and needs to be elucidated. In this work, we proposed an efficiency strategy, i.e., targeted degradation of BRD4 by ROS-activatable NanoPROTACs, for the treatment of liver fibrosis, both in vitro and in vivo. More importantly, we clarified the mechanism by which BRD4 regulates liver fibrosis. Thus, this strategy may represent an alternative to previously reported strategies and may be extensively applied to the design of ROS-activatable proteolysis-targeting chimeras for the treatment of other organ fibrosis.

Lactylation: A Novel Epigenetic Regulator of Cellular Senescence

Cellular senescence is the basic unit of organismal aging, a complicated biological process involving several cell types and tissues. It is also an important mechanism by which the body responds to damage and potential carcinogenesis. However, excessive or abnormal cellular senescence can lead to tissue functional degradation and the occurrence of diseases. In recent years, the role of epigenetic modifications in cellular senescence has received extensive attention. Lactylation, a novel post-translational modification derived from lactate, has recently gained significant attention as a key factor in cellular metabolism and epigenetic regulation, gradually demonstrating its importance in the regulation of cellular senescence. This review emphasizes the bidirectional causal relationship between lactylation and cellular senescence, highlighting its potential as a therapeutic target for aging-related diseases.

Mesenchymal stromal cells in bone marrow niche of patients with multiple myeloma: a double-edged sword

Multiple myeloma (MM) is a hematological malignancy defined by the abnormal proliferation and accumulation of plasma cells (PC) within the bone marrow (BM). While multiple myeloma impacts the bone, it is not classified as a primary bone cancer. The bone marrow microenvironment significantly influences the progression of myeloma and its treatment response. Mesenchymal stromal cells (MSCs) in this environment engage with myeloma cells and other bone marrow components via direct contact and the secretion of soluble factors. This review examines the established roles of MSCs in multiple facets of MM pathology, encompassing their pro-inflammatory functions, contributions to tumor epigenetics, effects on immune checkpoint inhibitors (ICIs), influence on reprogramming, chemotherapy resistance, and senescence. This review investigates the role of MSCs in the development and progression of MM.

Lysine crotonylation in disease: mechanisms, biological functions and therapeutic targets

Lysine crotonylation (Kcr), a previously unknown post-translational modification (PTM), plays crucial roles in regulating cellular processes, including gene expression, chromatin remodeling, and cellular metabolism. Kcr is associated with various diseases, including neurodegenerative disorders, cancer, cardiovascular conditions, and metabolic syndromes. Despite advances in identifying crotonylation sites and their regulatory enzymes, the molecular mechanisms by which Kcr influences disease progression remain poorly understood. Understanding the interplay between Kcr and other acylation modifications may reveal opportunities for developing targeted therapies. This review synthesizes current research on Kcr, focusing on its regulatory mechanisms and disease associations, and highlights insights into future exploration in epigenetics and therapeutic interventions.

Role of Protein Lysine Acetylation in the Pathogenesis and Treatment of Obesity and Metabolic Syndrome

PURPOSE OF REVIEW

This review aimed to highlight the known role of histone deacetylases (HDACs) and lysine acetyltransferases (KATs) in individuals with obesity, better understand the role of HDACs and KATs enzymes in obesity and related metabolic disorders.

RECENT FINDINGS

Numerous cellular activities, including DNA replication, DNA repair, cell cycle regulation, RNA splicing, signal transmission, metabolic function, protein stability, transportation, and transcriptional regulation, are influenced by lysine acetylation. Protein lysine acetylation serves several purposes, which not only contribute to the development of metabolic disorders linked to obesity but also hold promise for therapeutic approaches. The current study demonstrates that HDACs and KATs control lysine acetylation. This review details the advancements made in the study of obesity, related metabolic diseases, and protein lysine acetylation. It contributes to our understanding of the function and mechanism of protein lysine acetylation in obesity and MS and offers a fresh method for treating these diseases.

Lactylation: a promising therapeutic target in ischemia-reperfusion injury management

Ischemia-reperfusion injury (IRI) is a critical condition that poses a significant threat to patient safety. The production of lactate increases during the process of IRI, and lactate serves as a crucial indicator for assessing the severity of such injury. Lactylation, a newly discovered post-translational modification in 2019, is induced by lactic acid and predominantly occurs on lysine residues of histone or nonhistone proteins. Extensive studies have demonstrated the pivotal role of lactylation in the pathogenesis and progression of various diseases, including melanoma, myocardial infarction, hepatocellular carcinoma, Alzheimer's disease, and nonalcoholic fatty liver disease. Additionally, a marked correlation between lactylation and inflammation has been observed. This article provides a comprehensive review of the mechanism underlying lactylation in IRI to establish a theoretical foundation for better understanding the interplay between lactylation and IRI.

Elevated NAD+ drives Sir2A-mediated GCβ deacetylation and OES localization for Plasmodium ookinete gliding and mosquito infection

cGMP signal-activated ookinete gliding is essential for mosquito midgut infection of Plasmodium in malaria transmission. During ookinete development, cGMP synthesizer GCβ polarizes to a unique localization "ookinete extrados site" (OES) until ookinete maturation and activates cGMP signaling for initiating parasite motility. However, the mechanism underlying GCβ translocation from cytosol to OES remains elusive. Here, we use protein proximity labeling to search the GCβ-interacting proteins in ookinetes of the rodent malaria parasite P. yoelii, and find the top hit Sir2A, a NAD+-dependent sirtuin family deacetylase. Sir2A interacts with GCβ throughout ookinete development. In mature ookinetes, Sir2A co-localizes with GCβ at OES in a mutually dependent manner. Parasites lacking Sir2A lose GCβ localization at OES, ookinete gliding, and mosquito infection, phenocopying GCβ deficiency. GCβ is acetylated at gametocytes but is deacetylated by Sir2A for OES localization at mature ookinetes. We further demonstrate that the level of NAD+, an essential co-substrate for sirtuin, increases during the ookinete development. NAD+ at its maximal level in mature ookinetes promotes Sir2A-catalyzed GCβ deacetylation, ensuring GCβ localization at OES. This study highlights the spatiotemporal coordination of cytosolic NAD+ level and NAD+-dependent Sir2A in regulating GCβ deacetylation and dynamic localization for Plasmodium ookinete gliding.

HAT1/HDAC2 mediated ACSL4 acetylation confers radiosensitivity by inducing ferroptosis in nasopharyngeal carcinoma

Protein acetylation modification plays important roles in various aspects of tumor progression. Ferroptosis driven by lethal lipid peroxidation is closely related to tumor development. Targeting ferroptosis has become a promising strategy. However, the crosstalk between protein acetylation and ferroptosis remains unclear. In present study, we found that the acetylation of acyl-CoA synthase long-chain family member 4 (ACSL4) enhances its protein stability and a double-edged sword regulation in nasopharyngeal carcinoma (NPC). On the one hand, ACSL4 could promote the malignant progress of tumors; on the other hand, it enhanced radiosensitivity by endowing NPC cells with ferroptosis-sensitive properties in vitro and in vivo. Mechanistically, histone acetyltransferase 1 (HAT1) directly promotes the acetylation of ACSL4 at lysine 383, and deacetylase sirtuin 3 (SIRT3) mediates the deacetylation of ACSL4. Meanwhile, another deacetylase histone deacetylase 2 (HDAC2) enhances ACSL4 acetylation through inhibiting the transcription of SIRT3. Acetylation of ACSL4 inhibits F-box protein 10 (FBXO10)-mediated K48-linked ubiquitination, resulting in enhanced protein stability of ACSL4. This study reveals the novel regulatory mechanism of ferroptosis-related protein from the perspective of protein acetylation, and provides a novel method for the radiosensitivity of NPC.

Identification of molecular determinants of gene-specific bursting patterns by high-throughput imaging screens

Stochastic transcriptional bursting is a universal property of active genes. While different genes exhibit distinct bursting patterns, the molecular mechanisms that govern gene-specific stochastic bursting are largely unknown. We have developed a high-throughput-imaging-based screening strategy to identify cellular factors that determine the bursting patterns of native genes in human cells. We identify protein acetylation as a prominent effector of burst frequency and burst size acting via decreasing off-times and gene-specific changes in the on-time. These effects are not correlated with promoter acetylation. Instead, we demonstrate acetylation of the Integrator complex as a key determinant of gene bursting that alters Integrator interactions with transcription elongation and RNA processing factors but without affecting pausing. Our results suggest a prominent role for non-histone acetylation of a transcription cofactors as a mechanism for modulation of bursting via a far-downstream checkpoint.

SLC25A1 and ACLY maintain cytosolic acetyl-CoA and regulate ferroptosis susceptibility via FSP1 acetylation

Ferroptosis, an iron-dependent form of programmed cell death characterized by excessive lipid hydroperoxides accumulation, emerges as a promising target in cancer therapy. Among the solute carrier (SLC) superfamily, the cystine/glutamate transporter system antiporter components SLC3A2 and SLC7A11 are known to regulate ferroptosis by facilitating cystine import for ferroptosis inhibition. However, the contribution of additional SLC superfamily members to ferroptosis remains poorly understood. Here, we use a targeted CRISPR-Cas9 screen of the SLC superfamily to identify SLC25A1 as a critical ferroptosis regulator in human cancer cells. SLC25A1 drives citrate export from the mitochondria to the cytosol, where it fuels acetyl-CoA synthesis by ATP citrate lyase (ACLY). This acetyl-CoA supply sustains FSP1 acetylation and prevents its degradation by the proteasome via K29-linked ubiquitin chains. K168 is the primary site of FSP1 acetylation and deacetylation by KAT2B and HDAC3, respectively. Pharmacological inhibition of SLC25A1 and ACLY significantly enhances cancer cell susceptibility to ferroptosis both in vitro and in vivo. Targeting the SLC25A1-ACLY axis is therefore a potential therapeutic strategy for ferroptosis-targeted cancer intervention.

Protein lactylation in cancer: mechanisms and potential therapeutic implications

Increased glycolysis, which leads to high lactate production, is a common feature of cancer cells. Recent evidence suggests that lactate plays a role in the post-translational modification of histone and nonhistone proteins via lactylation. In contrast to genetic mutations, lactylation in cancer cells is reversible. Thus, reversing lactylation can be exploited as a pharmacological intervention for various cancers. Here we discuss recent advances in histone and nonhistone lactylation in cancer, including L-, D- and S-lactylation, as well as alanyl-tRNA synthetase as a novel lactyltransferase. We also discuss potential approaches for targeting lactylation as a therapeutic opportunity in cancer treatment.

HPV E6/E7-Induced Acetylation of a Peptide Encoded by a Long Non-Coding RNA Inhibits Ferroptosis to Promote the Malignancy of Cervical Cancer

Although a fraction of functional peptides concealed within long non-coding RNAs (lncRNAs) is identified, it remains unclear whether lncRNA-encoded peptides are involved in the malignancy of cervical cancer (CC). Here, a 92-amino acid peptide is discovered, which is named TUBORF, encoded by lncRNA TUBA3FP and highly expressed in CC tissues. TUBORF inhibits ferroptosis to promote the malignant proliferation of CC cells. Mechanistically, human papillomavirus (HPV) oncogenes E6 and E7 upregulate TUBORF through CREB-binding protein (CBP)/E1A-binding protein p300 (p300)-mediated histone H3 lysine 27 acetylation (H3K27ac) of lncTUBA3FP enhancer. Furthermore, E6 and E7 elevate and recruit acetyltransferase establishment of sister chromatid cohesion N-acetyltransferase 1 (ESCO1) to bind to and acetylate TUBORF, which facilitates the degradation of immunity-related GTPase Q (IRGQ) via a ubiquitin-proteasome pathway, resulting in the inhibition of ferroptosis and promotion of the malignant proliferation of CC cells. Importantly, silencing ESCO1 or TURORF amplifies anticancer effects by paclitaxel both in CC cells and in vivo. These novel findings reveal oncopeptide TUBORF and its acetyltransferase ESCO1 as important regulators of ferroptosis and tumorigenesis during cervical cancer pathogenesis and establish the scientific basis for targeting these molecules for treating CC.

Insights on post-translational modifications in fatty liver and fibrosis progression

Metabolic dysfunction-associated steatotic liver disease [MASLD] is a pervasive multifactorial health burden. Post-translational modifications [PTMs] of amino acid residues in protein domains demonstrate pivotal roles for imparting dynamic alterations in the cellular micro milieu. The crux of identifying novel druggable targets relies on comprehensively studying the etiology of metabolic disorders. This review article presents how different chemical moieties of various PTMs like phosphorylation, methylation, ubiquitination, glutathionylation, neddylation, acetylation, SUMOylation, lactylation, crotonylation, hydroxylation, glycosylation, citrullination, S-sulfhydration and succinylation presents the cause-effect contribution towards the MASLD spectra. Additionally, the therapeutic prospects in the management of liver steatosis and hepatic fibrosis via targeting PTMs and regulatory enzymes are also encapsulated. This review seeks to understand the function of protein modifications in progression and promote the markers discovery of diagnostic, prognostic and drug targets towards MASLD management which could also halt the progression of a catalogue of related diseases.

Hydroxycitric acid reconstructs damaged articular cartilages by modifying the metabolic cascade in chondrogenic cells

Objective

Osteoarthritis, a degenerative joint disease, requires innovative therapies due to the limited ability of cartilage to regenerate. Since mesenchymal stem cells (MSCs) provide a cell source for chondrogenic cells, we hypothesize that chemicals capable of enhancing the chondrogenic potential of MSCs with transforming growth factor-beta (TGFβ) in vitro may similarly promote chondrogenesis in articular cartilage in vivo.

Design

Chemical compounds that enhance the TGFβ signaling for chondrogenesis were investigated utilizing mesenchymal stem cells derived from human induced pluripotent stem cells. The mechanisms of action underlying the identified compound were explored in vitro, and its therapeutic effects were validated in vivo using a mouse model of exercise-induced osteoarthritis.

Results

Hydroxycitric acid (HCA) emerged as the lead compound. In vitro, HCA effectively enhanced chondrogenesis by inhibiting ATP citrate lyase, inducing citrate and alpha-ketoglutarate (α-KG), while reducing cytosolic acetyl coenzyme A (Ac-CoA). This induction of α-KG promoted collagen prolyl-4-hydroxylase activity, boosting hydroxyproline production and matrix formation. The reduction of Ac-CoA attenuated the inhibitory effect of β-catenin on mitochondrial activity by diminishing its acetylation. In vivo, orally administered HCA accumulated in joint tissues of mice and histological examination demonstrated newly synthesized cartilage tissues in damaged area. Analysis of joint tissue extracts revealed a downregulation of Ac-CoA and an upregulation of citrate and α-KG, accompanied by a systemic increase in an anabolic biomarker.

Conclusions

HCA demonstrates promise as an osteoarthritis therapy by enhancing chondrogenic differentiation. Its ability to modulate crucial metabolic pathways and facilitate cartilage repair suggests potential for clinical translation, addressing a critical need in the treatment of osteoarthritis.

ACSS2 drives senescence-associated secretory phenotype by limiting purine biosynthesis through PAICS acetylation

Senescence-associated secretory phenotype (SASP) mediates the biological effects of senescent cells on the tissue microenvironment and contributes to ageing-associated disease progression. ACSS2 produces acetyl-CoA from acetate and epigenetically controls gene expression through histone acetylation under various circumstances. However, whether and how ACSS2 regulates cellular senescence remains unclear. Here, we show that pharmacological inhibition and deletion of Acss2 in mice blunts SASP and abrogates the pro-tumorigenic and immune surveillance functions of senescent cells. Mechanistically, ACSS2 directly interacts with and promotes the acetylation of PAICS, a key enzyme for purine biosynthesis. The acetylation of PAICS promotes autophagy-mediated degradation of PAICS to limit purine metabolism and reduces dNTP pools for DNA repair, exacerbating cytoplasmic chromatin fragment accumulation and SASP. Altogether, our work links ACSS2-mediated local acetyl-CoA generation to purine metabolism through PAICS acetylation that dictates the functionality of SASP, and identifies ACSS2 as a potential senomorphic target to prevent senescence-associated diseases.

Exploring Alternative Zinc-Binding Groups in Histone Deacetylase (HDAC) Inhibitors Uncovers as a Potent Ethylhydrazide-Based HDAC Inhibitor with Chemosensitizing Properties

In this work, we synthesized a series of peptoid-based histone deacetylase (HDAC) inhibitors with variations in the linker region and zinc-binding groups. All compounds were investigated for their HDAC inhibition, antiplasmodial activity, and cytotoxicity against native and cisplatin-resistant carcinoma cell lines. The ethylhydrazide 20 (DS-103) proved to be the most effective compound in these primary screenings. DS-103 showed nanomolar inhibition of class I HDACs and of HDAC6 (class IIb). To further investigate the binding mode of DS-103, a crystal structure of DS-103 in complex with HDAC6 was obtained, which represents the first reported crystal structure of an alkylhydrazide in complex with an HDAC enzyme. Importantly, DS-103 completely reversed cisplatin resistance in two different platinum-resistant solid cancer cell lines and demonstrated strong synergism with cisplatin. The synergistic anticancer effects are mediated by increased DNA damage and p21 expression, resulting in caspase-mediated apoptosis and cell death.

JMJD6 K375 acetylation restrains lung cancer progression by enhancing METTL14/m6A/SLC3A2 axis mediated cell ferroptosis

BACKGROUND

The Jumonji domain-containing protein 6 (JMJD6), a histone arginine demethylase, is known to have a multifaceted and significant role on cancer progression. However, the specific function and mechanism of JMJD6 in non-small cell lung cancer (NSCLC) have yet to be fully elucidated.

METHODS

The elevated expression of JMJD6 in lung cancer tissues was confirmed through a combination of bioinformatics and immunohistochemical analysis. Utilizing lung cancer cell lines H460, H157, A549, and H1299, we further investigated the impact of JMJD6 on various cellular processes such as ferroptosis, proliferation, migration, and invasion both in vivo and in vitro. The acetylation of JMJD6 was characterized using immunoprecipitation, co-immunoprecipitation, GST pull down, and immunofluorescence techniques. The regulatory role of JMJD6 acetylation in ferroptosis was assessed by measuring levels of ROS, MDA, and JC-1. WB, qRT-PCR, ChIP and MeRIP techniques were employed to investigate the relationship between the JMJD6 acetylation/METTL14/m6A/SLC3A2 axis.

RESULTS

This study revealed elevated levels of JMJD6 in tumor tissue, with high expression correlating strongly with advanced clinical stage in lung cancer patients, and identified JMJD6 as a significantly poor prognostic factor for lung cancer. Functional experiments verified that ectopic overexpression of JMJD6 enhanced the proliferation and migratory capacities of lung cancer cells, while JMJD6 knockdown showed opposite effects. We further find that JMJD6 functions as a negative modulator in regulating ferroptosis process. Mechanistically, JMJD6 affects METTL14 expression in an arginine demethylase dependent manner, and mediates m6A modification of SLC3A2 to regulate its expression level, thereby affecting the sensitivity of lung cancer cells to ferroptosis. Besides, our findings indicate that acetyltransferase p300/CBP associated factor (PCAF) interacts with and acetylates JMJD6 at lysine 375. Acetylation weakens the activity of JMJD6 demethylase, thereby enhancing METTL14 expression and affecting its mediated m6A modification to regulate SLC3A2. Acetylation at lysine 375 also augment the modulation of ferroptosis in lung cancer cells by JMJD6, consequently impeding the lung cancer progression.

CONCLUSION

Taken together, we elucidated the JMJD6 acetylation/METTL14/m6A/SLC3A2 axis as a key mediator of lung cancer progression, indicating that JMJD6 may serve as a potentially prognostic biomarker and therapeutic target for NSCLC.

Aeromonas hydrophila CobQ is a new type of NAD+- and Zn2+-independent protein lysine deacetylase

Protein NƐ-lysine acetylation (Kac) modifications play crucial roles in diverse physiological and pathological functions in cells. In prokaryotic cells, there are only two types of lysine deacetylases (KDACs) that are Zn2+- or NAD+-dependent. In this study, we reported a protein, AhCobQ, in Aeromonas hydrophila ATCC 7966 that presents NAD+- and Zn2+-independent KDAC activity. Furthermore, its KDAC activity is located in an unidentified domain (from 195 to 245 aa). Interestingly, AhCobQ has no homology with current known KDACs, and no homologous protein was found in eukaryotic cells. A protein substrate analysis showed that AhCobQ has specific protein substrates in common with other known KDACs, indicating that these KDACs can dynamically co-regulate the states of Kac proteins. Microbiological methods employed in this study affirmed AhCobQ's positive regulation of isocitrate dehydrogenase (ICD) enzymatic activity at the K388 site, implicating AhCobQ in the modulation of bacterial enzymatic activities. In summary, our findings present compelling evidence that AhCobQ represents a distinctive type of KDAC with significant roles in bacterial biological functions.

Proteomic Comparison of Acute Myeloid Leukemia Cells and Normal CD34+ Bone Marrow Cells: Studies of Leukemia Cell Differentiation and Regulation of Iron Metabolism/Ferroptosis

Acute myeloid leukemia (AML) is an aggressive bone marrow malignancy that can be cured only by intensive chemotherapy possibly combined with allogeneic stem cell transplantation. We compared the pretreatment proteomic profiles of AML cells derived from 50 patients at the time of first diagnosis with normal CD34+ bone marrow cells. A comparison based on all AML and CD34+ normal cell populations identified 121 differentially abundant proteins that showed at least 2-fold differences, and these proteins included several markers of neutrophil differentiation (e.g., TLR2, the integrins ITGM and ITGX, and downstream mediators including RHO GTPase, S100A8, S100A9, S100A22). However, the expression of these 121 proteins varied between patients, and a subset of 28 patients was characterized by increased long-term AML-free survival, signs of myeloid AML cell differentiation, and favorable genetic abnormalities. These two main patient subsets (28 with differentiation versus 22 with fewer signs of differentiation) also differed with regard to the phosphorylation of 16 differentially abundant proteins. Furthermore, we also classified our patients based on their expression of 16 proteins involved in the regulation of iron metabolism/ferroptosis and showing differential expression when comparing AML cells and normal CD34+ cells. Among the 22 patients with less favorable prognosis, we could then identify a genetically heterogeneous subset characterized by adverse prognosis (i.e., death from primary resistance/relapse) and an iron metabolism/ferroptosis protein profile showing similarities with normal CD34+ cells. We conclude that proteomic profiles differ between AML and normal CD34+ cells; especially, proteomic differences reflecting differentiation and regulation of iron metabolism/ferroptosis are associated with risk of relapse after intensive conventional therapy.

Lysine acetylation in cyanobacteria: emerging mechanisms and functions

Cyanobacteria are ancient and abundant photosynthetic prokaryotes that play crucial roles in global carbon and nitrogen cycles. They exist in a variety of environments and have been used extensively as model organisms for studies of photosynthesis and environmental adaptation. Lysine acetylation (Kac), a widespread and evolutionarily conserved protein posttranslational modification, is reversibly catalyzed by lysine acetyltransferases (KAT) and lysine deacetylases (KDACs). Over the past decade, a growing number of acetylated proteins have been identified in cyanobacteria, and Kac is increasingly recognized as having essential roles in many cellular processes, such as photosynthesis, energy metabolism, and stress responses. Recently, cGNAT2 and CddA were identified as KAT and KDAC in the model cyanobacterium Synechococcus sp. PCC 7002, respectively. The identified Kac regulatory enzymes provide novel insight into the mechanisms that globally regulate photosynthesis in cyanobacteria and potentially other photosynthetic organisms. This review summarizes recent progress in our understanding of the functions and mechanisms of lysine acetylation in Cyanobacteria. The challenges and future perspectives in this field are also discussed.

Expression, purification, and crystallization of "humanized" Danio rerio histone deacetylase 10 "HDAC10", the eukaryotic polyamine deacetylase

The class IIb histone deacetylase HDAC10 is responsible for the deacetylation of intracellular polyamines, in particular N8-acetylspermidine. HDAC10 is emerging as an attractive target for drug design owing to its role as an inducer of autophagy, and high-resolution crystal structures enable structure-based drug design efforts. The only crystal structure available to date is that of HDAC10 from Danio rerio (zebrafish), but a construct containing the A24E and D94A substitutions yields an active site contour that more closely resembles that of human HDAC10. The use of this "humanized" construct has advanced our understanding of HDAC10-inhibitor structure-activity relationships. Here, we outline the preparation, purification, assay, and crystallization of humanized zebrafish HDAC10-inhibitor complexes. The plasmid containing the humanized zebrafish HDAC10 construct for heterologous expression in Escherichia coli is available through Addgene (#225542).

PRMT1-mediated methylation regulates MLL2 stability and gene expression

The interplay between multiple transcription factors precisely regulates eukaryotic transcription. Here, we report that the protein methyltransferases, MLL2/KMT2B and PRMT1, interact directly and act collectively to regulate gene expression. PRMT1 binds to the N-terminal region of MLL2, considered an intrinsically disordered region, and methylates multiple arginine residues within its RGG/RG motifs. Notably, overexpression of PRMT1 decreased poly-ubiquitylation of MLL2, whereas mutations on methylation sites in MLL2 increased MLL2 poly-ubiquitylation, suggesting that PRMT1-mediated methylation stabilizes MLL2. MLL2 and PRMT1 cooperatively stimulated the expression of a chromosomal reporter gene in a PRMT1-mediated, MLL2-methylation-dependent manner. RNA-seq analysis found that MLL2 and PRMT1 jointly regulate the expression of genes involved in cell membrane and extracellular matrix functions, and depletion of either resulted in impaired cell migration and invasion. Our study provides evidence that PRMT1-mediated MLL2 methylation regulates MLL2 protein stability and the expression of their target genes.

Identifying Sex Differences in Lung Adenocarcinoma Using Multi-Omics Integrative Protein Signaling Networks

Lung adenocarcinoma (LUAD) exhibits differences between the sexes in incidence, prognosis, and therapy, suggesting underexplored molecular mechanisms. We conducted an integrative multi-omics analysis using the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and The Cancer Genome Atlas (TCGA) datasets to contrast transcriptomes and proteomes between sexes. We used TIGER to analyze TCGA-LUAD expression data and found sex-biased activity of transcription factors (TFs); we used PTM-SEA with CPTAC-LUAD proteomics data and found sex-biased kinase activity. We combined these to construct a kinase-TF signaling network and discovered druggable pathways linked to cancer-related processes. We also found significant sex biases in clinically relevant TFs and kinases, including NR3C1, AR, and AURKA. Using the PRISM drug screening database, we identified potential sex-specific drugs, such as glucocorticoid receptor agonists and aurora kinase inhibitors. Our findings emphasize the importance of considering sex and using multi-omics network methods to discover personalized cancer therapies.

Novel histone deacetylase-5 inhibitor T2943 exerts an anti-depressive effect in mice by enhancing GRID1 expression

Histone deacetylase-5 (HDAC5) is implicated in the pathogenesis of depression and the mechanistic pathways underlying the effects of antidepressant medications. We previously identified a novel HDAC5 inhibitor, T2943, with antidepressant properties that promote histone 3 lysine-14 acetylation (H3K14ac) by inhibiting HDAC5 activity. In this study, we identify the core genes promoting transcription and expression following T2943-mediated upregulation of H3K14ac, highlighting Grid1 (GluD1) as a central gene. We used cleavage under targets and tagmentation (CUT&Tag), gene set enrichment analysis, and behavioral tests after GRID1 (glutamate receptor delta-1 subunit) knockdown. Gene ontology and pathway enrichment analysis via CUT&Tag suggested the following mechanism for the antidepressant action of T2943: T2943 inhibits HDAC5 activity to promote H3K14 acetylation. This modification loosens the chromatin structure, allowing transcription factors to bind to the Grid1 promoter region and enhance its transcription and expression. Upregulated GRID1 mediates signal transmission in neural pathways, restores the regenerative ability of hippocampal nerve cells, promotes nerve growth and synaptic formation, increases synapse numbers, and enhances synaptic function. Our findings highlight the therapeutic potential of targeting HDAC5 in depression and clarify the antidepressant mechanism of T2943.

Implication of protein post translational modifications in gastric cancer

Gastric cancer (GC) is one of the most common and highly lethal malignant tumors worldwide, and its occurrence and development are regulated by multiple molecular mechanisms. Post-translational modifications (PTM) common forms include ubiquitylation, phosphorylation, acetylation and methylation. Emerging research has highlighted lactylation and glycosylation. The diverse realm of PTM and PTM crosstalk is linked to many critical signaling events involved in neoplastic transformation, carcinogenesis and metastasis. This review provides a comprehensive overview of the impact of PTM on the occurrence and progression of GC. Specifically, aberrant PTM have been shown to alter the proliferation, migration, and invasion capabilities of GC cells. Moreover, PTM are closely associated with resistance to chemotherapeutic agents in GC. Notably, this review also discusses the phenomenon of PTM crosstalk, highlighting the interactions among PTM and their roles in regulating signaling pathways and protein functions. Therefore, in-depth investigation into the mechanisms of PTM and the development of targeted therapeutic strategies hold promise for advancing early diagnosis, treatment, and prognostic evaluation of GC, offering novel insights and future research directions.