o8G Site-Specifically Modified tRF-1-AspGTC: A Novel Therapeutic Target and Biomarker for Pulmonary Hypertension.

RATIONALE: Hypoxia and oxidative stress contribute to the development of pulmonary hypertension (PH). tRNA-derived fragments play important roles in RNA interference and cell proliferation, but their epitranscriptional roles in PH development have not been investigated. OBJECTIVE: We aimed to gain insight into the mechanistic contribution of oxidative stress-induced 8-oxoguanine in pulmonary vascular remodeling. METHODS AND RESULTS: Through small RNA modification array analysis and quantitative polymerase chain reaction, a significant upregulation of the 8-oxoguanine-modified tRF-1-AspGTC was found in the lung tissues and the serum of patients with PH. This modification occurs at the fifth 8-oxoguanine (5o8G) tRF in the seed region of the tRNA-derived fragments. Inhibition of the 5o8G tRF reversed hypoxia-induced proliferation and apoptosis resistance in pulmonary artery smooth muscle cells. Further investigation unveiled that the 5o8G tRF retargeted mRNA of WNT5A and CASP3 and inhibited their expression. Ultimately, BMPR2 (bone morphogenetic protein receptor 2)-reactive oxygen species/5o8G tRF/WNT5A signaling pathway exacerbated the progression of PH. CONCLUSIONS: Our study highlights the role of site-specific 8-oxoguanine-modified tRF in promoting the development of PH. Our findings present a promising therapeutic avenue for managing PH and propose 5o8G tRF as a potential innovative marker for diagnosing this disease.

Na+/K+-ATPase: ion pump, signal transducer, or cytoprotective protein, and novel biological functions.

Na+/K+-ATPase is a transmembrane protein that has important roles in the maintenance of electrochemical gradients across cell membranes by transporting three Na+ out of and two K+ into cells. Additionally, Na+/K+-ATPase participates in Ca2+-signaling transduction and neurotransmitter release by coordinating the ion concentration gradient across the cell membrane. Na+/K+-ATPase works synergistically with multiple ion channels in the cell membrane to form a dynamic network of ion homeostatic regulation and affects cellular communication by regulating chemical signals and the ion balance among different types of cells. Therefore, it is not surprising that Na+/K+-ATPase dysfunction has emerged as a risk factor for a variety of neurological diseases. However, published studies have so far only elucidated the important roles of Na+/K+-ATPase dysfunction in disease development, and we are lacking detailed mechanisms to clarify how Na+/K+-ATPase affects cell function. Our recent studies revealed that membrane loss of Na+/K+-ATPase is a key mechanism in many neurological disorders, particularly stroke and Parkinson's disease. Stabilization of plasma membrane Na+/K+-ATPase with an antibody is a novel strategy to treat these diseases. For this reason, Na+/K+-ATPase acts not only as a simple ion pump but also as a sensor/regulator or cytoprotective protein, participating in signal transduction such as neuronal autophagy and apoptosis, and glial cell migration. Thus, the present review attempts to summarize the novel biological functions of Na+/K+-ATPase and Na+/K+-ATPase-related pathogenesis. The potential for novel strategies to treat Na+/K+-ATPase-related brain diseases will also be discussed.

Targeting NKAα1 to treat Parkinson's disease through inhibition of mitophagy-dependent ferroptosis.

Dysfunction of the Na+/K+-ATPase (NKA) has been documented in various neurodegenerative diseases, yet the specific role of NKAα1 in Parkinson's disease (PD) remains incompletely understood. In this investigation, we utilized NKAα1 haploinsufficiency (NKAα1+/-) mice to probe the influence of NKAα1 on dopaminergic (DA) neurodegeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our findings reveal that NKAα1+/- mice displayed a heightened loss of DA neurons and more pronounced motor dysfunction compared to the control group when exposed to MPTP. Intriguingly, this phenomenon coincided with the activation of ferroptosis and impaired mitophagy both in vivo and in vitro. To scrutinize the role and underlying mechanism of NKAα1 in PD, we employed DR-Ab, an antibody targeting the DR-region of the NKA α subunit. Our study demonstrates that the administration of DR-Ab effectively reinstated the membrane abundance of NKAα1, thereby mitigating MPTP-induced DA neuron loss and subsequent improvement in behavioral deficit. Mechanistically, DR-Ab heightened the formation of the surface NKAα1/SLC7A11 complex, inhibiting SLC7A11-dependent ferroptosis. Moreover, DR-Ab disrupted the cytosolic interaction between NKAα1 and Parkin, facilitating the translocation of Parkin to mitochondria and enhancing the process of mitophagy. In conclusion, this study establishes NKAα1 as a key regulator of ferroptosis and mitophagy, identifying its DR-region as a promising therapeutic target for PD.

Disruption of the Na+/K+-ATPase-purinergic P2X7 receptor complex in microglia promotes stress-induced anxiety.

Na+/K+-ATPase (NKA) plays an important role in the central nervous system. However, little is known about its function in the microglia. Here, we found that NKAα1 forms a complex with the purinergic P2X7 receptor (P2X7R), an adenosine 5'-triphosphate (ATP)-gated ion channel, under physiological conditions. Chronic stress or treatment with lipopolysaccharide plus ATP decreased the membrane expression of NKAα1 in microglia, facilitated P2X7R function, and promoted microglia inflammatory activation via activation of the NLRP3 inflammasome. Accordingly, global deletion or conditional deletion of NKAα1 in microglia under chronic stress-induced aggravated anxiety-like behavior and neuronal hyperexcitability. DR5-12D, a monoclonal antibody that stabilizes membrane NKAα1, improved stress-induced anxiety-like behavior and ameliorated neuronal hyperexcitability and neurogenesis deficits in the ventral hippocampus of mice. Our results reveal that NKAα1 limits microglia inflammation and may provide a target for the treatment of stress-related neuroinflammation and diseases.

ErbB3 Governs Endothelial Dysfunction in Hypoxia-Induced Pulmonary Hypertension.

BACKGROUND: Pulmonary hypertension, characterized by vascular remodeling, currently lacks curative therapeutic options. The dysfunction of pulmonary artery endothelial cells plays a pivotal role in the initiation and progression of pulmonary hypertension (PH). ErbB3 (human epidermal growth factor receptor 3), also recognized as HER3, is a member of the ErbB family of receptor tyrosine kinases. METHODS: Microarray, immunofluorescence, and Western blotting analyses were conducted to investigate the pathological role of ErbB3. Blood samples were collected for biomarker examination from healthy donors or patients with hypoxic PH. The pathological functions of ErbB3 were further validated in rodents subjected to chronic hypoxia- and Sugen-induced PH, with or without adeno-associated virus-mediated ErbB3 overexpression, systemic deletion, or endothelial cell-specific ErbB3 knockdown. Primary human pulmonary artery endothelial cells and pulmonary artery smooth muscle cells were used to elucidate the underlying mechanisms. RESULTS: ErbB3 exhibited significant upregulation in the serum, lungs, distal pulmonary arteries, and pulmonary artery endothelial cells isolated from patients with PH compared with those from healthy donors. ErbB3 overexpression stimulated hypoxia-induced endothelial cell proliferation, exacerbated pulmonary artery remodeling, elevated systolic pressure in the right ventricle, and promoted right ventricular hypertrophy in murine models of PH. Conversely, systemic deletion or endothelial cell-specific knockout of ErbB3 yielded opposite effects. Coimmunoprecipitation and proteomic analysis identified YB-1 (Y-box binding protein 1) as a downstream target of ErbB3. ErbB3 induced nuclear translocation of YB-1 and subsequently promoted hypoxia-inducible factor 1/2α transcription. A positive loop involving ErbB3-periostin-hypoxia-inducible factor 1/2α was identified to mediate the progressive development of this disease. MM-121, a human anti-ErbB3 monoclonal antibody, exhibited both preventive and therapeutic effects against hypoxia-induced PH. CONCLUSIONS: Our study reveals, for the first time, that ErbB3 serves as a novel biomarker and a promising target for the treatment of PH.

ADAR1 regulates vascular remodeling in hypoxic pulmonary hypertension through N1-methyladenosine modification of circCDK17.

Pulmonary hypertension (PH) is an extremely malignant pulmonary vascular disease of unknown etiology. ADAR1 is an RNA editing enzyme that converts adenosine in RNA to inosine, thereby affecting RNA expression. However, the role of ADAR1 in PH development remains unclear. In the present study, we investigated the biological role and molecular mechanism of ADAR1 in PH pulmonary vascular remodeling. Overexpression of ADAR1 aggravated PH progression and promoted the proliferation of pulmonary artery smooth muscle cells (PASMCs). Conversely, inhibition of ADAR1 produced opposite effects. High-throughput whole transcriptome sequencing showed that ADAR1 was an important regulator of circRNAs in PH. CircCDK17 level was significantly lowered in the serum of PH patients. The effects of ADAR1 on cell cycle progression and proliferation were mediated by circCDK17. ADAR1 affects the stability of circCDK17 by mediating A-to-I modification at the A5 and A293 sites of circCDK17 to prevent it from m1A modification. We demonstrate for the first time that ADAR1 contributes to the PH development, at least partially, through m1A modification of circCDK17 and the subsequent PASMCs proliferation. Our study provides a novel therapeutic strategy for treatment of PH and the evidence for circCDK17 as a potential novel marker for the diagnosis of this disease.

DR region of NKAα1 is a target to ameliorate hepatic lipid metabolism disturbance in obese mice.

BACKGROUND: Na+/K+-ATPase (NKA), an ion pumping enzyme ubiquitously expressed in various cells, is critically involved in cellular ion homeostasis and signal transduction. However, the role of NKA in hepatic lipid homeostasis has yet to be fully characterized. METHODS: The activity of NKA and NKAα1 expression were determined in steatotic cells, mice and patients. The roles of NKAα1 in hepatosteatosis were detected using hepatocyte knockout or specific overexpression of NKAα1 in mice. RESULTS: Herein, we demonstrated that the expression and activity of α1 subunit of NKA (NKAα1) were lowered in the livers of nonalcoholic fatty liver disease (NAFLD) patients, high-fat diet (HFD)-induced obese mice, and genetically obese (ob/ob, db/db) mice, as well as oleic acid-induced hepatocytes. Hepatic deficiency of NKAα1 exacerbated, while adeno-associated virus-mediated liver specific overexpression of NKAα1 alleviated hepatic steatosis through regulation of fatty acid oxidation (FAO) and lipogenesis. Mechanistically, we revealed that NKAα1 upregulated sirtuin 1 (SIRT1) via interacting with ubiquitin specific peptidase 22 (USP22), a deubiquitinating enzyme for the stabilization and deubiquitination of SIRT1, thus activating the downstream autophagy signaling. Blockade of the SIRT1/autophagy signaling pathway eliminated the protective effects of NKAα1 against lipid deposition in hepatocytes. Importantly, we found that an antibody against the DR region (897DVEDSYGQQWTYEQR911) of NKAα1 subunit (DR-Ab) ameliorated hepatic steatosis through maintaining the membrane density of NKAα1 and inducing its activation. CONCLUSIONS: Collectively, this study renews the functions of NKAα1 in liver lipid metabolism and provides a new clue for gene therapy or antibody treatment of hepatic lipid metabolism disturbance by targeting NKAα1.

Targeting the Na+/K+ ATPase DR-region with DR-Ab improves doxorubicin-induced cardiotoxicity.

Doxorubicin (DOX) is a potent chemotherapeutic drug for various cancers. Yet, the cardiotoxic side effects limit its application in clinical uses, in which ferroptosis serves as a crucial pathological mechanism in DOX-induced cardiotoxicity (DIC). A reduction of Na+/K + ATPase (NKA) activity is closely associated with DIC progression. However, whether abnormal NKA function was involved in DOX-induced cardiotoxicity and ferroptosis remains unknown. Here, we aim to decipher the cellular and molecular mechanisms of dysfunctional NKA in DOX-induced ferroptosis and investigate NKA as a potential therapeutic target for DIC. A decrease activity of NKA further aggravated DOX-triggered cardiac dysfunction and ferroptosis in NKAα1 haploinsufficiency mice. In contrast, antibodies against the DR-region of NKAα-subunit (DR-Ab) attenuated the cardiac dysfunction and ferroptosis induced by DOX. Mechanistically, NKAα1 interacted with SLC7A11 to form a novel protein complex, which was directly implicated in the disease progression of DIC. Furthermore, the therapeutic effect of DR-Ab on DIC was mediated by reducing ferroptosis by promoting the association of NKAα1/SLC7A11 complex and maintaining the stability of SLC7A11 on the cell surface. These results indicate that antibodies targeting the DR-region of NKA may serve as a novel therapeutic strategy to alleviate DOX-induced cardiotoxicity.

Antioxidant and Anti-Inflammatory Effects of 6,3',4´- and 7,3´,4´-Trihydroxyflavone on 2D and 3D RAW264.7 Models.

Dietary flavones 6,3´,4´-trihydroxyflavone (6,3´,4´-HOFL) and 7,3´,4´-trihydroxyflavone (7,3´,4´-HOFL) showed preliminary antioxidant and anti-inflammatory activities in a two-dimensional (2D) cell culture model. However, their action mechanisms remain unclear, and the anti-inflammatory activities have not been studied in a reliable three-dimensional (3D) cell model. Therefore, in the current study, the antioxidant potency was examined by their scavenging ability of cellular reactive oxygen species. Anti-inflammatory activities were examined via their inhibitory effects on inflammatory mediators in vitro on 2D and 3D macrophage models, and their mechanisms were determined through transcriptome. In the 3D macrophages, two flavones were less bioactive than they were in 2D macrophages, but they both significantly suppressed the overexpression of proinflammatory mediators in two cell models. The divergent position of the hydroxyl group on the A ring resulted in activity differences. Compared to 6,3´,4´-HOFL, 7,3´,4´-HOFL showed lower activity on NO, IL-1ß suppression, and c-Src binding (IC50: 12.0 and 20.9 µM) but higher ROS-scavenging capacity (IC50: 3.20 and 2.71 µM) and less cytotoxicity. In addition to the IL-17 and TNF pathways of 6,3´,4´-HOFL, 7,3´,4´-HOFL also exerted anti-inflammatory activity through JAK-STAT, as indicated by the RNA-sequencing results. Two flavones showed prominent antioxidant and anti-inflammatory activities on 2D and 3D models.

Polysulfide Protects Against Diabetic Cardiomyopathy Through Sulfhydration of Peroxisome Proliferator-Activated Receptor-γ and Sirtuin 3.

Aims: Diabetic cardiomyopathy (DCM) is characterized by cardiac dysfunction and heart failure. However, the effective therapy for DCM is still lacking. Polysulfide contains chains of sulfur atoms, and accumulative evidence has shown that it actively participates in mammalian physiology or pathophysiology. Nevertheless, the potential effects and mechanisms of polysulfide in DCM need further investigation. In the present study, Na2S4, a polysulfide donor, was employed to investigate the therapeutic effects of polysulfide in DCM. Results: Our results showed that Na2S4 protected cardiomyocytes against high glucose (HG)-induced cardiomyocyte injury. The pathological changes in DCM including cell death, oxidative stress, mitochondrial dysfunction and cardiac hypertrophy were improved by Na2S4 treatment. The left ventricular contractile function in streptozotocin (STZ)-induced diabetic mice was significantly improved by Na2S4. Mechanistically, Na2S4 upregulated and sulfhydrated peroxisome proliferator-activated receptor-γ (PPARγ) and sirtuin 3 (SIRT-3) in cardiomyocytes. Suppression of PPARγ or SIRT-3 with their specific inhibitors or blockade of sulfhydration abolished the protective effects of Na2S4. Moreover, mutations of PPARγ or SIRT-3 at specific cysteines diminished the benefits of Na2S4 in HG-challenged cardiomyocytes. Innovation and Conclusion: We demonstrated that Na2S4 prevented the development of DCM via sulfhydration of both PPARγ and SIRT-3. Our results imply that polysulfide may be a potential and promising agent to treat DCM. Antioxid. Redox Signal. 38, 1-17.

Hydrogen Sulfide in Diabetic Complications Revisited: The State of the Art, Challenges, and Future Directions.

Significance: Diabetes and its related complications are becoming an increasing public health problem that affects hundreds of millions of people globally. Increased disability and mortality rate of diabetic individuals are closely associated with various life-threatening complications, such as atherosclerosis, nephropathy, retinopathy, and cardiomyopathy. Recent Advances: Conventional treatments for diabetes are still limited because of undesirable side effects, including obesity, hypoglycemia, and hepatic and renal toxicity. Studies have shown that hydrogen sulfide (H2S) plays a critical role in the modulation of glycolipid metabolism, pancreatic ß cell functions, and diabetic complications. Critical Issues: Preservation of endogenous H2S systems and supplementation of H2S donors are effective in attenuating diabetes-induced complications, thus representing a new avenue to treat diabetes and its associated complications. Future Directions: This review systematically recapitulates and discusses the most recent updates regarding the therapeutic effects of H2S on diabetes and its various complications, with an emphasis on the molecular mechanisms that underlie H2S-mediated protection against diabetic complications. Furthermore, current clinical trials of H2S in diabetic populations are highlighted, and the challenges and solutions to the clinical transformation of H2S-derived therapies in diabetes are proposed. Finally, future research directions of the pharmacological actions of H2S in diabetes and its related complications are summarized. Antioxid. Redox Signal. 38, 18-44.

Recent Advances in the Study of Na+/K+-ATPase in Neurodegenerative Diseases.

Na+/K+-ATPase (NKA), a large transmembrane protein, is expressed in the plasma membrane of most eukaryotic cells. It maintains resting membrane potential, cell volume and secondary transcellular transport of other ions and neurotransmitters. NKA consumes about half of the ATP molecules in the brain, which makes NKA highly sensitive to energy deficiency. Neurodegenerative diseases (NDDs) are a group of diseases characterized by chronic, progressive and irreversible neuronal loss in specific brain areas. The pathogenesis of NDDs is sophisticated, involving protein misfolding and aggregation, mitochondrial dysfunction and oxidative stress. The protective effect of NKA against NDDs has been emerging gradually in the past few decades. Hence, understanding the role of NKA in NDDs is critical for elucidating the underlying pathophysiology of NDDs and identifying new therapeutic targets. The present review focuses on the recent progress involving different aspects of NKA in cellular homeostasis to present in-depth understanding of this unique protein. Moreover, the essential roles of NKA in NDDs are discussed to provide a platform and bright future for the improvement of clinical research in NDDs.

The Landscape of Noncoding RNA in Pulmonary Hypertension.

The transcriptome of pulmonary hypertension (PH) is complex and highly genetically heterogeneous, with noncoding RNA transcripts playing crucial roles. The majority of RNAs in the noncoding transcriptome are long noncoding RNAs (lncRNAs) with less circular RNAs (circRNAs), which are two characteristics gaining increasing attention in the forefront of RNA research field. These noncoding transcripts (especially lncRNAs and circRNAs) exert important regulatory functions in PH and emerge as potential disease biomarkers and therapeutic targets. Recent technological advancements have established great momentum for discovery and functional characterization of ncRNAs, which include broad transcriptome sequencing such as bulk RNA-sequence, single-cell and spatial transcriptomics, and RNA-protein/RNA interactions. In this review, we summarize the current research on the classification, biogenesis, and the biological functions and molecular mechanisms of these noncoding RNAs (ncRNAs) involved in the pulmonary vascular remodeling in PH. Furthermore, we highlight the utility and challenges of using these ncRNAs as biomarkers and therapeutics in PH.

Therapeutic potential of carbon monoxide in hypertension-induced vascular smooth muscle cell damage revisited: From physiology and pharmacology.

As a chronic and progressive disorder, hypertension remains to be a serious public health problem around the world. Among the different types of hypertension, pulmonary arterial hypertension (PAH) is a devastating disease associated with pulmonary arteriole remodeling, right ventricular failure and death. The contemporary management of systemic hypertension and PAH has substantially grown since more therapeutic targets and/or agents have been developed. Evolving treatment strategies targeting the vascular remodeling lead to improving outcomes in patients with hypertension, nevertheless, significant advancement opportunities for developing better antihypertensive drugs remain. Carbon monoxide (CO), an active endogenous gasotransmitter along with hydrogen sulfide (H2S) and nitric oxide (NO), is primarily generated by heme oxygenase (HO). Cumulative evidence suggests that CO is considered as an important signaling molecule under both physiological and pathological conditions. Studies have shown that CO confers a number of biological and pharmacological properties, especially its involvement in the pathological process and treatment of hypertension-related vascular remodeling. This review will critically outline the roles of CO in hypertension-associated vascular remodeling and discuss the underlying mechanisms for the protective effects of CO against hypertension and vascular remodeling. In addition, we will propose the challenges and perspectives of CO in hypertensive vascular remodeling. It is expected that a comprehensive understanding of CO in the vasculature might be essential to translate CO to be a novel pharmacological agent for hypertension-induced vascular remodeling.

Role of Na+/K+-ATPase in ischemic stroke: in-depth perspectives from physiology to pharmacology.

Na+/K+-ATPase (NKA) is a large transmembrane protein expressed in all cells. It is well studied for its ion exchanging function, which is indispensable for the maintenance of electrochemical gradients across the plasma membrane and herein neuronal excitability. The widely recognized pump function of NKA closely depends on its unique structure features and conformational changes upon binding of specific ions. Various Na+-dependent secondary transport systems are rigorously controlled by the ionic gradients generated by NKA and are essential for multiple physiological processes. In addition, roles of NKA as a signal transducer have also been unveiled nowadays. Plethora of signaling cascades are defined including Src-Ras-MAPK signaling, IP3R-mediated calcium oscillation, inflammation, and autophagy though most underlying mechanisms remain elusive. Ischemic stroke occurs when the blood flow carrying nutrients and oxygen into the brain is disrupted by blood clots, which is manifested by excitotoxicity, oxidative stress, inflammation, etc. The protective effect of NKA against ischemic stress is emerging gradually with the application of specific NKA inhibitor. However, NKA-related research is limited due to the opposite effects caused by NKA inhibitor at lower doses. The present review focuses on the recent progression involving different aspects about NKA in cellular homeostasis to present an in-depth understanding of this unique protein. Moreover, essential roles of NKA in ischemic pathology are discussed to provide a platform and bright future for the improvement in clinical research on ischemic stroke.

An Updated Insight Into Molecular Mechanism of Hydrogen Sulfide in Cardiomyopathy and Myocardial Ischemia/Reperfusion Injury Under Diabetes.

Cardiovascular diseases are the most common complications of diabetes, and diabetic cardiomyopathy is a major cause of people death in diabetes. Molecular, transcriptional, animal, and clinical studies have discovered numerous therapeutic targets or drugs for diabetic cardiomyopathy. Within this, hydrogen sulfide (H2S), an endogenous gasotransmitter alongside with nitric oxide (NO) and carbon monoxide (CO), is found to play a critical role in diabetic cardiomyopathy. Recently, the protective roles of H2S in diabetic cardiomyopathy have attracted enormous attention. In addition, H2S donors confer favorable effects in myocardial infarction, ischaemia-reperfusion injury, and heart failure under diabetic conditions. Further studies have disclosed that multiplex molecular mechanisms are responsible for the protective effects of H2S against diabetes-elicited cardiac injury, such as anti-oxidative, anti-apoptotic, anti-inflammatory, and anti-necrotic properties. In this review, we will summarize the current findings on H2S biology and pharmacology, especially focusing on the novel mechanisms of H2S-based protection against diabetic cardiomyopathy. Also, the potential roles of H2S in diabetes-aggravated ischaemia-reperfusion injury are discussed.

H2S Donor and Bone Metabolism.

Hydrogen sulfide (H2S) has been recognized as the third gasotransmitter, following nitric oxide and carbon monoxide, and it exerts important biological effects in the body. Growing evidence has shown that H2S is involved in many physiological processes in the body. In recent years, much research has been carried out on the role of H2S in bone metabolism. Bone metabolic diseases have been linked to abnormal endogenous H2S functions and metabolism. It has been found that H2S plays an important role in the regulation of bone diseases such as osteoporosis and osteoarthritis. Regulation of H2S on bone metabolism has many interacting signaling pathways at the molecular level, which play an important role in bone formation and absorption. H2S releasing agents (donors) have achieved significant effects in the treatment of metabolic bone diseases such as osteoporosis and osteoarthritis. In addition, H2S donors and related drugs have been widely used as research tools in basic biomedical research and may be explored as potential therapeutic agents in the future. Donors are used to study the mechanism and function of H2S as they release H2S through different mechanisms. Although H2S releasers have biological activity, their function can be inconsistent. Additionally, donors have different H2S release capabilities, which could lead to different effects. Side effects may form with the formation of H2S; however, it is unclear whether these side effects affect the biological effects of H2S. Therefore, it is necessary to study H2S donors in detail. In this review, we summarize the current information about H2S donors related to bone metabolism diseases and discuss some mechanisms and biological applications.

The Role of H2S in the Metabolism of Glucose and Lipids.

Glucose and lipids are essential elements for maintaining the body's homeostasis, and their dysfunction may participate in the pathologies of various diseases, particularly diabetes, obesity, metabolic syndrome, cardiovascular ailments, and cancers. Among numerous endogenous mediators, the gasotransmitter hydrogen sulfide (H2S) plays a central role in the maintenance of glucose and lipid homeostasis. Current evidence from both pharmacological studies and transgenic animal models suggest a complex relationship between H2S and metabolic dysregulation, especially in diabetes and obesity. This notion is achieved through tissue-specific expressions and actions of H2S on target metabolic and hormone organs including the pancreas, skeletal muscle, livers, and adipose. In this chapter, we will summarize the roles and mechanisms of H2S in several metabolic organs/tissues that are necessary for glucose and lipid metabolic homeostasis. In addition, future research directions and valuable therapeutic avenues around the pharmacological regulation of H2S in glycolipid metabolism disorder will be also discussed.

Highly recurrent CBS epimutations in gastric cancer CpG island methylator phenotypes and inflammation.

BACKGROUND: CIMP (CpG island methylator phenotype) is an epigenetic molecular subtype, observed in multiple malignancies and associated with the epigenetic silencing of tumor suppressors. Currently, for most cancers including gastric cancer (GC), mechanisms underlying CIMP remain poorly understood. We sought to discover molecular contributors to CIMP in GC, by performing global DNA methylation, gene expression, and proteomics profiling across 14 gastric cell lines, followed by similar integrative analysis in 50 GC cell lines and 467 primary GCs. RESULTS: We identify the cystathionine beta-synthase enzyme (CBS) as a highly recurrent target of epigenetic silencing in CIMP GC. Likewise, we show that CBS epimutations are significantly associated with CIMP in various other cancers, occurring even in premalignant gastroesophageal conditions and longitudinally linked to clinical persistence. Of note, CRISPR deletion of CBS in normal gastric epithelial cells induces widespread DNA methylation changes that overlap with primary GC CIMP patterns. Reflecting its metabolic role as a gatekeeper interlinking the methionine and homocysteine cycles, CBS loss in vitro also causes reductions in the anti-inflammatory gasotransmitter hydrogen sulfide (H2S), with concomitant increase in NF-κB activity. In a murine genetic model of CBS deficiency, preliminary data indicate upregulated immune-mediated transcriptional signatures in the stomach. CONCLUSIONS: Our results implicate CBS as a bi-faceted modifier of aberrant DNA methylation and inflammation in GC and highlights H2S donors as a potential new therapy for CBS-silenced lesions.