Hydrogen Sulfide Attenuates Inflammatory Hepcidin by Reducing IL-6 Secretion and Promoting SIRT1-Mediated STAT3 Deacetylation

Critical re-evaluation of the identification of iron deficiency states and effective iron repletion strategies in patients with chronic heart failure

According to current guidelines, iron deficiency is defined by a serum ferritin level <100 ng/ml or a transferrin saturation (TSAT) <20% if the serum ferritin level is 100-299 μg/L. These criteria were developed to encourage the use of intravenous iron as an adjunct to erythropoiesis-stimulating agents in the treatment of renal anaemia. However, in patients with heart failure, these criteria are not supported by any pathophysiological or clinical evidence that they identify an absolute or functional iron deficiency state. A low baseline TSAT-but not serum ferritin level-appears to be a reliable indicator of the effect of intravenous iron to reduce major heart failure events. In randomized controlled trials, intravenous iron decreased the risk of cardiovascular death or total heart failure hospitalization in patients with a TSAT <20% (risk ratio 0.67 [0.49-0.92]) but not in patients with a TSAT ≥20% (risk ratio 0.99 [0.74-1.30]), with the magnitude of the risk reduction being proportional to the severity of hypoferraemia. Patients who were enrolled in clinical trials solely because they had a serum ferritin level <100 μg/L showed no significant benefit on heart failure outcomes, and it is noteworthy that serum ferritin levels of 20-300 μg/L lie entirely within the range of normal values for healthy adults. Current guidelines reflect the eligibility criteria of clinical trials, which inadvertently adopted unvalidated criteria to define iron deficiency. Reliance on these guidelines would lead to the treatment of many patients who are not iron deficient (serum ferritin level <100 μg/L but normal TSAT) and ignores the possibility of iron deficiency in patients with a low TSAT but with serum ferritin level of >300 μg/L. Importantly, analyses of benefit based on trial eligibility-driven guidelines substantially underestimate the magnitude of heart-failure-event risk reduction with intravenous iron in patients who are truly iron deficient. Based on all available data, we recommend a new mechanism-based and trial-tested approach that reflects the totality of evidence more faithfully than the historical process adopted by clinical investigators and by the guidelines. Until additional evidence is forthcoming, an iron deficiency state in patients with heart failure should be defined by a TSAT <20% (as long as the serum ferritin level is <400 μg/L), and furthermore, the use of a serum ferritin level <100 μg/L alone as a diagnostic criterion should be discarded.

Exploring the moderating effects of SIRT1 and gene polymorphisms rs7895833 on the relationship between hemoglobin levels and physical frailty in elderly adults with comorbid chronic diseases: A moderated mediation analysis

Background

Relationship age, hemoglobin, and physical frailty have all been investigated in older people with more than one chronic disease. There has been little analysis of the relationship between hemoglobin, age, physical frailty, plasma levels of Sirtuin1 (SIRT1), and the gene polymorphism (SNP) rs7895833 A>G. The goal of this study was to find out how SIRT1 level, SNP rs7895833, hemoglobin, age, and physical frailty (frail score) are related in older Indonesian adults with comorbid chronic diseases.

Methods

This was an observational study. Demographic and clinical data were retrieved from the electronic health records of Universitas Sumatera Utara Hospital, Medan, Indonesia. Physical frailty, SIRT1 level, and SNP rs7895833 were measured using an appropriate and valid method. Purposive sampling was used to determine the eligibility of 132 elderly adults from November 2022 to February 2023.

Results

The indirect effect of hemoglobin on the frail score (FS) through age was negative and significant, according to a conditional mediation analysis (β=-0.0731; p=0.023). Meanwhile, the direct effect of hemoglobin on the FS was negative and not significant (β=0.1632; p=0.052). According to the conditional moderated mediation analysis, the size of the direct effect of age on FS was increased by genotype AG-GG and SIRT1 level (β low=0.2647; p=0.002, β middle=0.2956; p<0.001, and β high=0.319; p<0.001). The size of the conditional indirect effect of Hemoglobin on FS through age was negative and significantly increased by SNP genotype AG-GG and SIRT1 level (β low=-0.0647; p=0.032, β middle=-0.0723; p=0.024, and β high=-0.078; p=0.02).

Conclusions

Higher plasma levels of SIRT1 and the SNP genotype AG-GG may both contribute to physical frailty in the elderly population. Hemoglobin levels in the blood fall with age, which can negatively impact older persons who already have chronic diseases. However, the interactions between these factors are intricate, requiring more study to completely understand the processes underlying development.

Proliferation, migration and phenotypic transformation of VSMC induced via Hcy related to up-expression of WWP2 and p-STAT3

To provide a theoretical basis for the prevention and treatment of atherosclerosis (AS), the current study aimed to investigate the mechanism underlying the effect of homocysteine (Hcy) on regulating the proliferation, migration and phenotypic transformation of vascular smooth muscle cells (VSMC) via sirtuin-1 (SIRT1)/signal transducer and activator of transcription 3 (STAT3) through Nedd4-like E3 ubiquitin-protein ligase WWP2 (WWP2). Here, Based on the establishment of ApoE-/- mouse models of high Hcy As and the model of Hcy stimulation of VSMC in vitro to observe the interaction between WWP2 and STAT3 and its effect on the proliferation, migration, and phenotypic transformation of Hcy-induced VSMC, which has not been previously reported. This study revealed that WWP2 could promote the proliferation, migration, and phenotype switch of Hcy-induced VSMC by up-regulating the phosphorylation of SIRT1/STAT3 signaling. Furthermore, Hcy might up-regulate WWP2 expression by inhibiting histone H3K27me3 expression through up-regulated UTX. These data suggest that WWP2 is a novel and important regulator of Hcy-induced VSMC proliferation, migration, and phenotypic transformation.

Mechanisms of enhanced renal and hepatic erythropoietin synthesis by sodium-glucose cotransporter 2 inhibitors

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of major heart failure events, an action that is statistically linked to enhanced erythropoiesis, suggesting that stimulation of erythropoietin and cardioprotection are related to a shared mechanism. Four hypotheses have been proposed to explain how these drugs increase erythropoietin production: (i) renal cortical reoxygenation with rejuvenation of erythropoietin-producing cells; (ii) counterregulatory distal sodium reabsorption leading to increased tubular workload and oxygen consumption, and thus, to localized hypoxia; (iii) increased iron mobilization as a stimulus of hypoxia-inducible factor-2α (HIF-2α)-mediated erythropoietin synthesis; and (iv) direct HIF-2α activation and enhanced erythropoietin gene transcription due to increased sirtuin-1 (SIRT1) signaling. The first two hypotheses assume that the source of increased erythropoietin is the interstitial fibroblast-like cells in the deep renal cortex. However, SGLT2 inhibitors do not alter regional tissue oxygen tension in the non-diabetic kidney, and renal erythropoietin synthesis is markedly impaired in patients with anemia due to chronic kidney disease, and yet, SGLT2 inhibitors produce an unattenuated erythrocytic response in these patients. This observation raises the possibility that the liver contributes to the production of erythropoietin during SGLT2 inhibition. Hypoxia-inducible factor-2α and erythropoietin are coexpressed not only in the kidney but also in hepatocytes; the liver is a major site of production when erythropoietin stimulation is maintained for prolonged periods. The ability of SGLT2 inhibitors to improve iron mobilization by derepressing hepcidin and ferritin would be expected to increase cytosolic ferrous iron, which might stimulate HIF-2α expression in both the kidney and liver through the action of iron regulatory protein 1. Alternatively, the established ability of SGLT2 inhibitors to enhance SIRT1 might be the mechanism of enhanced erythropoietin production with these drugs. In hepatic cell lines, SIRT1 can directly activate HIF-2α by deacetylation, and additionally, through an effect of SIRT in the liver, peroxisome proliferator-activated receptor-γ coactivator-1α binds to hepatic nuclear factor 4 to promote transcription of the erythropoietin gene and synthesis of erythropoietin. Since SIRT1 up-regulation exerts direct cytoprotective effects on the heart and stimulates erythropoietin, it is well-positioned to represent the shared mechanism that links erythropoiesis to cardioprotection during SGLT2 inhibition.

Nutritional Modulation of Hepcidin in the Treatment of Various Anemic States

Twenty years after its discovery, hepcidin is still considered the main regulator of iron homeostasis in humans. The increase in hepcidin expression drastically blocks the flow of iron, which can come from one's diet, from iron stores, and from erythrophagocytosis. Many anemic conditions are caused by non-physiologic increases in hepcidin. The sequestration of iron in the intestine and in other tissues poses worrying premises in view of discoveries about the mechanisms of ferroptosis. The nutritional treatment of these anemic states cannot ignore the nutritional modulation of hepcidin, in addition to the bioavailability of iron. This work aims to describe and summarize the few findings about the role of hepcidin in anemic diseases and ferroptosis, as well as the modulation of hepcidin levels by diet and nutrients.

Adipose tissue-derived mesenchymal stem cells ameliorate cognitive impairment in Alzheimer's disease rat model: Emerging role of SIRT1

Alzheimer's disease (AD) is a complex form of neurodegenerative dementia. Growing body of evidence supports the cardinal role of sirtuin1 (SIRT1) in neurodegeneration and AD development. Recently, adipose tissue-derived mesenchymal stem cells (Ad-MSCs) have made their mark for a wide array of regenerative medicine applications, including neurodegenerative disorders. Therefore, the present study aimed to investigate the therapeutic potential of Ad-MSCs in AD rat model, and to explore the possible implication of SIRT1. Ad-MSCs were isolated from rat epididymal fat pads and properly characterized. Aluminum chloride was used to induce AD in rats, and afterward, a group of AD-induced rats received a single dose of Ad-MSCs (2 × 106 cell, I.V per rat). One month after Ad-MSCs transplantation, behavioral tests were done, brain tissues were collected, then histopathological and biochemical assessments were performed. Amyloid beta and SIRT1 levels were determined by enzyme-linked immunosorbent assay. Whereas expression levels of neprilysin, BCL2 associated X protein, B-cell lymphoma-2, interleukin-1β, interleukin-6, and nerve growth factor in hippocampus and frontal cortex brain tissues were assessed using reverse transcriptase quantitative polymerase chain reaction. Our data demonstrated that transplantation of Ad-MSCs alleviated cognitive impairment in AD rats. Additionally, they exhibited anti-amyloidogenic, antiapoptotic, anti-inflammatory, as well as neurogenic effects. Furthermore, Ad-MSCs were found to possibly mediate their therapeutic effects, at least partially, via modulating both central and systemic SIRT1 levels. Hence, the current study portrays Ad-MSCs as an effective therapeutic approach for AD management and opens the door for future investigations to further elucidate the role of SIRT1 and its interrelated molecular mediators in AD.

Vinpocetine alleviates intestinal ischemia/reperfusion injury and enhances M2 macrophage polarization in rats: Role of SIRT1/SOCS3/STAT3 signaling pathway

Vinpocetine (Vinpo) is a neuroprotective vasodilator drug. It is an effective therapeutic agent for a variety of cerebrovascular and cognitive disorders. However, its potential protective efficacy on intestinal ischemia/reperfusion (I/R) injury remains elusive. The present study aimed to investigate the effect of Vinpo on intestinal I/R injury and to explore its modulatory effect on sirtuin (SIRT1)/ Suppressor of cytokine signaling (SOCS3)/ Signal Transducer and Activator of Transcription (STAT3) signaling. Twenty-four male Wistar albino rats were randomly allocated into four groups. G1 (sham): rats were subjected to surgical stress without I/R, GII (I/R): rats were subjected to 60 min/2-h I/R, GIII (Vinpo + I/R): rats were pre-treated with Vinpo (20 mg/kg/day, P.O. daily) for 2 weeks before intestinal I/R; GIV (EX527 + Vinpo + I/R): rats received both Vinpo (20 mg/kg/day, P.O.) and EX527 (5 mg/kg, once every 2 days, i.p) for 2 weeks before intestinal I/R. The current results showed that Vinpo improved the intestinal histopathological picture, enhanced M1 to M2 macrophage polarization and alleviated the I/R-induced increase in interleukins (IL-6, IL-1β), tumor necrosis factor (TNF-α), inducible nitric oxide synthase (i-NOS), and nitric oxide (NO). Additionally, Vinpo pretreatment upregulated SIRT1 mRNA expression/protein level and SOCS3 mRNA expression while downregulating P-STAT3 immunoreactivity. The effects of Vinpo were attenuated by the SIRT1 inhibitor EX527. We concluded that Vinpo ameliorated the intestinal I/R injury and enhanced M2 anti-inflammatory macrophage polarization through modulation of SIRT1/SOCS3/STAT3/i-NOS cascade.

Acetylation, ferroptosis, and their potential relationships: Implications in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a serious complication affecting the prognosis of patients with myocardial infarction and can cause cardiac arrest, reperfusion arrhythmias, no-reflow, and irreversible myocardial cell death. Ferroptosis, an iron-dependent, peroxide-driven, non-apoptotic form of regulated cell death, plays a vital role in reperfusion injury. Acetylation, an important post-translational modification, participates in many cellular signaling pathways and diseases, and plays a pivotal role in ferroptosis. Elucidating the role of acetylation in ferroptosis may therefore provide new insights for the treatment of MIRI. Here, we summarized the recently discovered knowledge about acetylation and ferroptosis in MIRI. Finally, we focused on the acetylation modification during ferroptosis and its potential relationship with MIRI.

SGLT2 inhibitors: role in protective reprogramming of cardiac nutrient transport and metabolism

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce heart failure events by direct action on the failing heart that is independent of changes in renal tubular function. In the failing heart, nutrient transport into cardiomyocytes is increased, but nutrient utilization is impaired, leading to deficient ATP production and the cytosolic accumulation of deleterious glucose and lipid by-products. These by-products trigger downregulation of cytoprotective nutrient-deprivation pathways, thereby promoting cellular stress and undermining cellular survival. SGLT2 inhibitors restore cellular homeostasis through three complementary mechanisms: they might bind directly to nutrient-deprivation and nutrient-surplus sensors to promote their cytoprotective actions; they can increase the synthesis of ATP by promoting mitochondrial health (mediated by increasing autophagic flux) and potentially by alleviating the cytosolic deficiency in ferrous iron; and they might directly inhibit glucose transporter type 1, thereby diminishing the cytosolic accumulation of toxic metabolic by-products and promoting the oxidation of long-chain fatty acids. The increase in autophagic flux mediated by SGLT2 inhibitors also promotes the clearance of harmful glucose and lipid by-products and the disposal of dysfunctional mitochondria, allowing for mitochondrial renewal through mitochondrial biogenesis. This Review describes the orchestrated interplay between nutrient transport and metabolism and nutrient-deprivation and nutrient-surplus signalling, to explain how SGLT2 inhibitors reverse the profound nutrient, metabolic and cellular abnormalities observed in heart failure, thereby restoring the myocardium to a healthy molecular and cellular phenotype.

S-Propargyl-Cysteine Ameliorates Peripheral Nerve Injury through Microvascular Reconstruction

Microvascular reconstruction is essential for peripheral nerve repair. S-Propargyl-cysteine (SPRC), the endogenous hydrogen sulfide (H₂S) donor, has been reported to promote angiogenesis. The aim of this study is to utilize the pro-angiogenic ability of SPRC to support peripheral nerve repair and to explore the potential mechanisms. The effects and mechanisms of SPRC on angiogenesis and peripheral nerve repair were examined under hypoxic condition by establishing a sciatic nerve crushed injury model in mice and rats, and a hypoxia model in human umbilical vascular endothelial cells (HUVECs) in vitro. We found that SPRC accelerated the function recovery of the injured sciatic nerve and alleviated atrophy of the gastrocnemius muscle in mice. It facilitated the viability of Schwann cells (SCs), the outgrowth and myelination of regenerated axons, and angiogenesis in rats. It enhanced the viability, proliferation, adhesion, migration, and tube formation of HUVECs under hypoxic condition. SPRC activated sirtuin1 (SIRT1) expression by promoting the production of endogenous H₂S, and SIRT1 negatively regulated Notch signaling in endothelial cells (ECs), thereby promoting angiogenesis. Collectively, our study has provided important evidence that SPRC has an effective role in peripheral nerve repair through microvascular reconstruction, which could be a potentially effective medical therapy for peripheral nerve injury.

Direct comparison of non-osteoarthritic and osteoarthritic synovial fluid-induced intracellular chondrocyte signaling and phenotype changes

OBJECTIVE

Since the joint microenvironment and tissue homeostasis are highly dependent on synovial fluid, we aimed to compare the essential chondrocyte signaling signatures of non-osteoarthritic vs end-stage osteoarthritic knee synovial fluid. Moreover, we determined the phenotypic consequence of the distinct signaling patterns on articular chondrocytes.

METHODS

Protein profiling of synovial fluid was performed using antibody arrays. Chondrocyte signaling and phenotypic changes induced by non-osteoarthritic and osteoarthritic synovial fluid were analyzed using a phospho-kinase array, luciferase-based transcription factor activity assays, and RT-qPCR. The origin of osteoarthritic synovial fluid signaling was evaluated by comparing the signaling responses of conditioned media from cartilage, synovium, infrapatellar fat pad and meniscus. Osteoarthritic synovial fluid induced pathway-phenotype relationships were evaluated using pharmacological inhibitors.

RESULTS

Compared to non-osteoarthritic synovial fluid, osteoarthritic synovial fluid was enriched in cytokines, chemokines and growth factors that provoked differential MAPK, AKT, NFκB and cell cycle signaling in chondrocytes. Functional pathway analysis confirmed increased activity of these signaling events upon osteoarthritic synovial fluid stimulation. Tissue secretomes of osteoarthritic cartilage, synovium, infrapatellar fat pad and meniscus activated several inflammatory signaling routes. Furthermore, the distinct pathway signatures of osteoarthritic synovial fluid led to accelerated chondrocyte dedifferentiation via MAPK/ERK signaling, increased chondrocyte fibrosis through MAPK/JNK and PI₃K/AKT activation, an elevated inflammatory response mediated by cPKC/NFκB, production of extracellular matrix-degrading enzymes by MAPK/p38 and PI₃K/AKT routes, and enabling of chondrocyte proliferation.

CONCLUSION

This study provides the first mechanistic comparison between non-osteoarthritic and osteoarthritic synovial fluid, highlighting MAPKs, cPKC/NFκB and PI₃K/AKT as crucial OA-associated intracellular signaling routes.

Potential Interactions When Prescribing SGLT2 Inhibitors and Intravenous Iron in Combination in Heart Failure

In patients with heart failure, sodium-glucose cotransporter 2 (SGLT2) inhibitors have been shown to decrease hepcidin and ferritin and increase transferrin receptor protein, changes that are typically indicative of worsening absolute iron deficiency, as would be seen with poor dietary intake or gastrointestinal bleeding, neither of which is provoked by SGLT2 inhibitors. Therefore, 2 alternative conceptual frameworks may explain the observed pattern of changes in iron homeostasis proteins. According to the "cytosolic iron depletion hypothesis," the effect of SGLT2 inhibitors to decrease hepcidin and ferritin and increase transferrin receptor is related to a decline in cytosolic Fe²⁺ that occurs after drug-induced erythropoietin-related increase in iron use. Erythropoietin-mimetics (eg, darbepoietin) elicit this type of iron-deficiency pattern of response, and it is typically accompanied by erythropoietin resistance that is alleviated by intravenous iron supplementation. In contrast, according to the "cytosolic iron repletion hypothesis," the effect of SGLT2 inhibitors to decrease hepcidin and ferritin and increase transferrin receptor represents a direct action of these drugs: 1) to reverse inflammation-related increases in hepcidin and ferritin, and, thus, alleviate functional blocks on iron utilization; and 2) to increase in sirtuin-1 signaling, which suppresses hepcidin, accelerates the degradation of ferritin, and up-regulates transferrin receptor protein. Through either or both mechanisms, direct suppression of hepcidin and ferritin would be expected to increase cytosolic Fe²⁺, thus allowing an unattenuated erythrocytic response to erythropoietin without the need for intravenous iron supplementation. The totality of clinical evidence supports the "cytosolic iron repletion hypothesis" because SGLT2 inhibitors elicit a full and sustained erythrocytosis in response to erythropoietin, even in overtly iron-deficient patients and in the absence of intravenous iron therapy. Therefore, the emergence of an iron-deficiency pattern of response during SGLT2 inhibition does not reflect worsening iron stores that are in need of replenishment, but instead, represents potential alleviation of a state of inflammation-related functional iron deficiency that is commonly seen in patients with chronic heart failure. Treatment with intravenous iron may be unnecessary and theoretically deleterious.

How can sodium-glucose cotransporter 2 inhibitors stimulate erythrocytosis in patients who are iron-deficient? Implications for understanding iron homeostasis in heart failure

Many patients with heart failure have an iron-deficient state, which can limit erythropoiesis in erythroid precursors and ATP production in cardiomyocytes. Yet, treatment with sodium-glucose cotransporter 2 (SGLT2) inhibitors produces consistent increases in haemoglobin and haematocrit, even in patients who are iron-deficient before treatment, and this effect remains unattenuated throughout treatment even though SGLT2 inhibitors further aggravate biomarkers of iron deficiency. Heart failure is often accompanied by systemic inflammation, which activates hepcidin, thus impairing the duodenal absorption of iron and the release of iron from macrophages and hepatocytes, leading to a decline in circulating iron. Inflammation and oxidative stress also promote the synthesis of ferritin and suppress ferritinophagy, thus impairing the release of intracellular iron stores and leading to the depletion of bioreactive cytosolic Fe2+ . By alleviating inflammation and oxidative stress, SGLT2 inhibitors down-regulate hepcidin, upregulate transferrin receptor protein 1 and reduce ferritin; the net result is to increase the levels of cytosolic Fe2+ available to mitochondria, thus enabling the synthesis of heme (in erythroid precursors) and ATP (in cardiomyocytes). The finding that SGLT2 inhibitors can induce erythrocytosis without iron supplementation suggests that the abnormalities in iron diagnostic tests in patients with mild-to-moderate heart failure are likely to be functional, rather than absolute, that is, they are related to inflammation-mediated trapping of iron by hepcidin and ferritin, which is reversed by treatment with SGLT2 inhibitors. An increase in bioreactive cytosolic Fe2+ is also likely to augment mitochondrial production of ATP in cardiomyocytes, thus retarding the progression of heart failure. These effects on iron metabolism are consistent with (i) proteomics analyses of placebo-controlled trials, which have shown that biomarkers of iron homeostasis represent the most consistent effect of SGLT2 inhibitors; and (ii) statistical mediation analyses, which have reported striking parallelism of the effect of SGLT2 inhibitors to promote erythrocytosis and reduce heart failure events.

Hydrogen Sulfide (H2S) Signaling as a Protective Mechanism against Endogenous and Exogenous Neurotoxicants

In view of the significant role of H₂S in brain functioning, it is proposed that H₂S may also possess protective effects against adverse effects of neurotoxicants. Therefore, the objective of the present review is to discuss the neuroprotective effects of H₂S against toxicity of a wide spectrum of endogenous and exogenous agents involved in the pathogenesis of neurological diseases as etiological factors or key players in disease pathogenesis. Generally, the existing data demonstrate that H₂S possesses neuroprotective effects upon exposure to endogenous (amyloid β, glucose, and advanced-glycation end-products, homocysteine, lipopolysaccharide, and ammonia) and exogenous (alcohol, formaldehyde, acrylonitrile, metals, 6-hydroxydopamine, as well as 1-methyl-4-phenyl- 1,2,3,6- tetrahydropyridine (MPTP) and its metabolite 1-methyl-4-phenyl pyridine ion (MPP)) neurotoxicants. On the one hand, neuroprotective effects are mediated by S-sulfhydration of key regulators of antioxidant (Sirt1, Nrf2) and inflammatory response (NF-κB), resulting in the modulation of the downstream signaling, such as SIRT1/TORC1/CREB/BDNF-TrkB, Nrf2/ARE/HO-1, or other pathways. On the other hand, H₂S appears to possess a direct detoxicative effect by binding endogenous (ROS, AGEs, Aβ) and exogenous (MeHg) neurotoxicants, thus reducing their toxicity. Moreover, the alteration of H₂S metabolism through the inhibition of H₂S-synthetizing enzymes in the brain (CBS, 3-MST) may be considered a significant mechanism of neurotoxicity. Taken together, the existing data indicate that the modulation of cerebral H₂S metabolism may be used as a neuroprotective strategy to counteract neurotoxicity of a wide spectrum of endogenous and exogenous neurotoxicants associated with neurodegeneration (Alzheimer's and Parkinson's disease), fetal alcohol syndrome, hepatic encephalopathy, environmental neurotoxicant exposure, etc. In this particular case, modulation of H₂S-synthetizing enzymes or the use of H₂S-releasing drugs should be considered as the potential tools, although the particular efficiency and safety of such interventions are to be addressed in further studies.

The effect of electroacupuncture on the expression of Sirt1 and STAT3 in hippocampus and amygdala of vascular dementia rats

OBJECTIVE

Inflammation has long been considered a key factor in learning and memory impairment in patients with vascular dementia (VaD). Studies have confirmed that electroacupuncture can improve the learning and memory impairment of patients with VaD by reducing inflammation, but the specific mechanism of this effect is still unclear. The aim of this study was to explore the underlying mechanism of electroacupuncture in the treatment of VaD.

METHODS

The vascular dementia animal model was established by bilateral occlusion of common carotid arteries, and electroacupuncture treatment was given at Baihui (DU20) and Zusanli (ST36). The morris water maze (MWM) was used to test the spatial learning and memory ability of rats in each group. To evaluate the expression of Sirtuin1 (Sirt1), Signal transducer and activator of transcription 3 (STAT3) and inflammatory cytokine (IL-17) in the hippocampus and amygdala, immunohistochemistry and western blot were performed.

RESULTS

The MWM test and Nissl staining results show that electroacupuncture can significantly improve the learning and memory impairment of VaD rats, and can repair damaged neurons. Immunohistochemistry and western blot results showed that electroacupuncture could enhance the expression of sirt1 in VaD rats, on the contrary, the expression of STAT3 and IL-17 was reduced due to electroacupuncture.

CONCLUSIONS

The result suggests that electroacupuncture can suppress inflammation through the Sirt1/STAT3 pathway and improve spatial learning and memory in VaD rats.

Hydrogen sulfide and metal interaction: the pathophysiological implications

Hydrogen sulfide (H₂S), previously recognized as a toxic gas, has emerged as an important gaseous signaling molecule along with nitric oxide, carbon monoxide and also hydrogen. H₂S can be endogenously produced in the mammalian body at a very low level for various pathophysiological processes. Notably, H₂S can interact with several essential metals in the body such as iron, copper, nickel, and zinc to carry out specific functions. The interactions of H₂S with metal-binding proteins have been shown to aid in its signal transduction and cellular metabolism. In addition, H₂S is capable of providing a cytoprotective role against metal toxicity. As the research in the field of H₂S signaling in biology and medicine increases, much progresses have been developed for detecting H₂S via interaction with metals. In this review, the interaction of H₂S with metals, specifically in regard to metal-driven metabolism of H₂S, the protection against metal toxicity by H₂S and the detection of H₂S using metals will be discussed. Discovering the interactions of this gasotransmitter with metals is important for determining the mechanisms underlying the cellular functions of H₂S as well as developing novel therapeutic avenues.

Research Progress of Ferroptosis in Adiposity-Based Chronic Disease (ABCD)

Ferroptosis is a multistep regulated cell death process induced by iron accumulation and lipid peroxidation. Classical GPX4-dependent pathway and GPX4-independent pathways can independently and synergistically inhibit ferroptosis and jointly maintain the oxidative balance of the body. WHO defines obesity as "a condition of abnormal or excessive fat accumulation in adipose tissue, to the extent that health may be impaired," and obesity is also defined as an adiposity-based chronic disease (ABCD). Obesity is a systemic disease that leads to metabolic abnormalities in various systems, resulting in a series of complications including obesity cardiomyopathy, atherosclerosis, nonalcoholic fatty liver disease, and diabetes mellitus. Emerging evidence shows that ferroptosis is closely associated with the occurrence and progression of various diseases. In recent years, ferroptosis has been found to play critical roles in obesity and its complications. This review discusses the mechanisms of how ferroptosis is initiated and controlled and discusses the research progress of ferroptosis in obesity and its complications.

Hirsutine ameliorates hepatic and cardiac insulin resistance in high-fat diet-induced diabetic mice and in vitro models

Closely associated with type 2 diabetes mellitus (T2DM), hepatic steatosis and cardiac hypertrophy resulting from chronic excess intake can exacerbate insulin resistance (IR). The current study aims to investigate the pharmacological effects of hirsutine, one indole alkaloid isolated from Uncaria rhynchophylla, on improving hepatic and cardiac IR, and elucidate the underlying mechanism. T2DM and IR in vivo were established by high-fat diet (HFD) feeding for 3 months in C57BL/6 J mice. In vitro IR models were induced by high-glucose and high-insulin (HGHI) incubation in HepG2 and H9c2 cells. Hirsutine administration for 8 weeks improved HFD-induced peripheral hyperglycemia, glucose tolerance and IR by OGTT and ITT assays, and simultaneously attenuated hepatic steatosis and cardiac hypertrophy by pathological observation. The impaired p-Akt expression was activated by hirsutine in liver and heart tissues of HFD mice, and also in the models in vitro. Hirsutine exhibited the effects on enhancing glucose consumption and uptake in IR cell models via activating phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which was blocked by PI3K inhibitor LY294002. Moreover, the effect of hirsutine on promoting glucose uptake and GLUT4 expression in HGHI H9c2 cells was also prevented by Compound C, an inhibitor of AMP-activated protein kinase (AMPK). Enhancement of glycolysis might be another factor of hirsutine showing its effects on glycemic control. Collectively, it was uncovered that hirsutine might exert beneficial effects on regulating glucose homeostasis, thus improving hepatic and cardiac IR, and could be a promising compound for treating diet-induced T2DM.

Hydrogen Sulfide Promotes Thyroid Hormone Synthesis and Secretion by Upregulating Sirtuin-1

Objective: One mechanism of hypothyroidism involves the disruption of thyroid hormone synthesis and secretion by thyrocytes. Hydrogen sulfide (H₂S), as a gas signaling molecule, participates in many physiopathologic processes by upregulating sirtuin-1 (SIRT1). The aim of the current study was to explore whether H₂S promotes the synthesis and secretion of thyroid hormones by upregulating SIRT1.

Methods: Real-time PCR and immunohistochemistry were used to detect the mRNA and protein expression of H₂S-generating enzymes in normal human thyroid tissues. Serum H₂S concentrations from hypothyroid patients (n = 32) and euthyroid participants (n = 41) were detected by H₂S-selective sensors. Thirty-one Sprague–Dawley rats were divided into control group (n = 10), hypothyroid group (induced by MMI, n = 10) and hypothyroid + NaHS group (n = 11), and the FT4, TT4 and TSH levels were assayed. Human primary thyrocytes were incubated with H₂S donor sodium hydrosulfide (NaHS) or NaHS plus SIRT1 inhibitor (EX527) in vitro. Thyroid hormone synthesis- and secretion-related proteins [thyroid peroxidase (TPO), sodium iodide transporter (NIS), Pendrin, monocarboxylic acid transporter 8 (MCT8)] were analyzed by real-time PCR and Western blot.

Results: H₂S levels in serum from hypothyroid patients were decreased compared to those from euthyroid participants (p < .05), and serum H₂S levels were positively correlated with FT3, FT4, TT3, and TT4 levels in all subjects (all p < .0001). In vivo, NaHS promoted thyroid function in hypothyroid rats (p < .05). In vitro, H₂S was detected in supernatant, and CBS mRNA was higher than CSE and 3-MPST in human primary thyrocytes (p < .05). The protein levels of TPO, NIS, Pendrin and MCT8 were upregulated in a concentration-dependent manner for NaHS in thyrocytes. After blocking SIRT1 with EX527, we found that the increasing levels of TPO, NIS, Pendrin, and MCT8 and TPO activity were downregulated in thyrocytes incubated with NaHS, and FT4 levels in the cell supernatant were also decreased significantly (all p < .05).

Conclusion: H₂S is mainly generated in thyrocytes by CBS. Serum H₂S levels are decreased with hypothyroidism. H₂S promotes the synthesis and secretion of thyroid hormones and the expression of related molecules by upregulating SIRT1.

Signaling Integration of Hydrogen Sulfide and Iron on Cellular Functions

Significance: Hydrogen sulfide (H₂S) is an endogenous signaling molecule, regulating numerous physiological functions from vasorelaxation to neuromodulation. Iron is a well-known bioactive metal ion, being the central component of hemoglobin for oxygen transportation and participating in biomolecule degradation, redox balance, and enzymatic actions. The interplay between H₂S and iron metabolisms and functions impacts significantly on the fate and wellness of different types of cells. Recent Advances: Iron level in vivo affects the production of H₂S via nonenzymatic reactions. On the contrary, H₂S quenches excessive iron inside the cells and regulates the redox status of iron. Critical Issues: Abnormal metabolisms of both iron and H₂S are associated with various conditions and diseases such as iron overload, anemia, oxidative stress, and cardiovascular and neurodegenerative diseases. The molecular mechanisms for the interactions between H₂S and iron are unsettled yet. Here we review signaling links of the production, metabolism, and their respective and integrative functions of H₂S and iron in normalcy and diseases. Future Directions: Physiological and pathophysiological importance of H₂S and iron as well as their therapeutic applications should be evaluated jointly, not separately. Future investigation should expand from iron-rich cells and tissues to the others, in which H₂S and iron interaction has not received due attention. Antioxid. Redox Signal. 36, 275-293.

Iron disorders and hepcidin

Iron is an essential element due to its role in a wide variety of physiological processes. Iron homeostasis is crucial to prevent iron overload disorders as well as iron deficiency anemia. The liver synthesized peptide hormone hepcidin is a master regulator of systemic iron metabolism. Given its role in overall health, measurement of hepcidin can be used as a predictive marker in disease states. In addition, hepcidin-targeting drugs appear beneficial as therapeutic agents. This review emphasizes recent development on analytical techniques (immunochemical, mass spectrometry and biosensors) and therapeutic approaches (hepcidin agonists, stimulators and antagonists). These insights highlight hepcidin as a potential biomarker as well as an aid in the development of new drugs for iron disorders.

Hydrogen Sulfide Actions in the Vasculature

Hydrogen sulfide (H2 S) is a small, gaseous molecule with poor solubility in water that is generated by multiple pathways in many species including humans. It acts as a signaling molecule in many tissues with both beneficial and pathological effects. This article discusses its many actions in the vascular system and the growing evidence of its role to regulate vascular tone, angiogenesis, endothelial barrier function, redox, and inflammation. Alterations in some disease states are also discussed including potential roles in promoting tumor growth and contributions to the development of metabolic disease. © 2021 American Physiological Society. Compr Physiol 11:1-22, 2021.

New Therapeutic Approaches Using Hydrogen Sulfide Donors in Inflammation and Immune Response

Significance: Inflammation and immune response are associated with many pathological disorders, including rheumatoid arthritis, lupus, heart failure, and cancer(s). In recent times, important roles of hydrogen sulfide (H₂S) have been evidenced by researchers in inflammatory responses, as well as immunomodulatory effects in several disease models. Recent Advances: Numerous biological targets, including cytochrome c oxidase, various kinases, enzymes involved in epigenetic changes, transcription factors, namely nuclear factor kappa B and nuclear factor erythroid 2-related factor 2, and several membrane ion channels, are shown to be sensitive to H₂S and have been widely investigated in various preclinical models. Critical Issues: A complete understanding of the effects of H₂S in inflammatory and immune response is vital in the development of novel H₂S generating therapeutics. In this review, the biological effects and pharmacological properties of H₂S in inflammation and immune response are addressed. The review also covers some of the novel H₂S releasing prodrugs developed in recent years as tools to study this fascinating molecule. Future Directions: H₂S plays important roles in inflammation and immunity-related processes. Future researches are needed to further assess the immunomodulatory effects of H₂S and to assist in the design of more efficient H₂S carrier systems, or drug formulations, for the management of immune-related conditions in humans. Antioxid. Redox Signal. 35, 341-356.

Hydrogen Sulfide and the Immune System

Hydrogen sulfide (H₂S) is the "third gasotransmitter" recognized alongside nitric oxide (NO) and carbon monoxide (CO). H₂S exhibits an array of biological effects in mammalian cells as revealed by studies showing important roles in the cardiovascular system, in cell signalling processes, post-translational modifications and in the immune system. Regarding the latter, using pharmacological and genetic approaches scientists have shown this molecule to have both pro- and anti-inflammatory effects in mammalian systems. The anti-inflammatory effects of H₂S appeared to be due to its inhibitory action on the nuclear factor kappa beta signalling pathway; NF-kB representing a transcription factor involved in the regulation pro-inflammatory mediators like nitric oxide, prostaglandins, and cytokines. In contrast, results from several animal model describe a more complicated picture and report on pro-inflammatory effects linked to exposure to this molecule; linked to dosage used and point of administration of this molecule. Overall, roles for H₂S in several inflammatory diseases spanning arthritis, atherosclerosis, sepsis, and asthma have been described by researchers. In light this work fascinating research, this chapter will cover H₂S biology and its many roles in the immune system.

A novel dendritic mesoporous silica based sustained hydrogen sulfide donor for the alleviation of adjuvant-induced inflammation in rats

Purpose

S-propargyl-cysteine (SPRC), an excellent endogenous hydrogen sulfide (H₂S) donor, could elevate H₂S levels via the cystathionine γ-lyase (CSE)/H₂S pathway both in vitro and in vivo. However, the immediate release of H₂S in vivo and daily administration of SPRC potentially limited its clinical use.

Methods

To solve the fore-mentioned problem, in this study, the dendritic mesoporous silica nanoparticles (DMSN) was firstly prepared, and a sustained H₂S delivery system consisted of SPRC and DMSN (SPRC@DMSN) was then constructed. Their release profiles, both in vitro and in vivo, were investigated, and their therapeutical effect toward adjuvant-induced arthritis (AIA) rats was also studied.

Results

The spherical morphology of DMSN could be observed under scanning Electron Microscope (SEM), and the transmission electron microscope (TEM) images showed a central-radiational pore channel structure of DMSN. DMSN showed excellent SPRC loading capacity and attaining a sustained releasing ability than SPRC both in vitro and in vivo, and the prolonged SPRC releasing could further promote the release of H₂S in a sustained manner through CSE/H₂S pathway both in vitro and in vivo. Importantly, the SPRC@DMSN showed promising anti-inflammation effect against AIA in rats was also observed.

Conclusions

A sustained H₂S releasing donor consisting of SPRC and DMSN was constructed in this study, and this sustained H₂S releasing donor might be of good use for the treatment of AIA.

The Preparation of a Novel Poly(Lactic Acid)-Based Sustained H2S Releasing Microsphere for Rheumatoid Arthritis Alleviation

Rheumatoid arthritis (RA) is a chronic, inflammatory autoimmune disease that mainly erodes joints and surrounding tissues, and if it is not treated in time, it can cause joint deformities and loss of function. S-propargyl-cysteine (SPRC) is an excellent endogenous hydrogen sulfide donor which can relieve the symptoms of RA through the promotion of H₂S release via the CSE/H₂S pathway in vivo. However, the instant release of H₂S in vivo could potentially limit its further clinical use. To solve this problem, in this study, a SPRC-loaded poly(lactic acid) (PLA) microsphere (SPRC@PLA) was prepared, which could release SPRC in vitro in a sustained manner, and further promote sustained in vivo H₂S release. Furthermore, its therapeutical effect on RA in rats was also studied. A spherical-like SPRC@PLA was successfully prepared with a diameter of approximately 31.61 μm, yielding rate of 50.66%, loading efficiency of 6.10% and encapsulation efficiency of 52.71%. The SPRC@PLA showed significant prolonged in vitro SPRC release, to 4 days, and additionally, an in vivo H₂S release around 3 days could also be observed. In addition, a better therapeutical effect and prolonged administration interval toward RA rats was also observed in the SPRC@PLA group.

SIRT1-autophagy axis inhibits excess iron-induced ferroptosis of foam cells and subsequently increases IL-1Β and IL-18

OBJECTIVE

Ferroptosis is a new form of programmed cell death characterized by an iron-dependent increase in lipid ROS. It has recently been reported that elevated iron levels in macrophages in plaques are associated with atherosclerosis(AS). However, it is not clear whether iron induces ferroptosis and the mechanism of ferroptosis induced by iron in macrophages in plaque.

METHODS

THP-1 macrophages were treated with ox-LDL and ferric ammonium citrate(FAC). Activate SIRT1 using SRT1720. Use of RAPA and CQ to promote and suppress autophagy. The expression of SIRT1, GPX4 was detected by Western Blot, and the cell activity and lipid ROS level were also performed. IL-1β and IL-18 levels were measured using qRT-PCR and ELISA.

RESULTS

In this study, we determined that FAC can induce a decrease in foam cell activity rather than macrophage activity, increase lipid ROS levels, decrease GPX4 expression and inhibit SIRT1 expression, and increase IL-1β and IL-18 levels. SRT1720 activated SIRT1 and reversed the above changes induced by FAC. CQ partially prevents the above changes caused by activating SIRT1.

CONCLUSION

Activation of SIRT1 can inhibit the ferroptosis and IL-1β and IL-18 levels of foam cells in excess iron by autophagy, providing a novel therapeutic target for AS.

Central Nervous System Inflammation Induced by Lipopolysaccharide Up-Regulates Hepatic Hepcidin Expression by Activating the IL-6/JAK2/STAT3 Pathway in Mice

It is known that lipopolysaccharide (LPS) triggers inflammatory response after intracerebroventricular (ICV) injection and elevates the expression of hepcidin through the interleukin 6/janus kinase 2/transducer and activator of the transcription 3 (IL-6/JAK2/STAT3) signaling pathway in the brain. This study was conducted to determine whether LPS ICV injection can regulate peripheral hepatic hepcidin expression and iron metabolism. Here, we studied the hepcidin expression in the liver, as well as serum iron and transferrin saturation, after LPS ICV injection. We also demonstrated the role of the IL-6/JAK2/STAT3 pathway in hepcidin expression in the livers of IL-6 knockout (IL-6–/– mice) and IL-6+/+ mice. AG490 was used to verify the effect of the IL-6/JAK2/STAT3 pathway on hepatic hepcidin expression. Our present study demonstrated that LPS ICV injection up-regulated hepatic hepcidin expression. This finding provides further evidence for highlighting the importance of the central inflammation on hepatic hepcidin expression and peripheral iron metabolism.

Hepcidin Upregulation in Lung Cancer: A Potential Therapeutic Target Associated With Immune Infiltration

Lung cancer has the highest death rate among cancers globally. Hepcidin is a fascinating regulator of iron metabolism; however, the prognostic value of hepcidin and its correlation with immune cell infiltration in lung cancer remain unclear. Here, we comprehensively clarified the prognostic value and potential function of hepcidin in lung cancer. Hepcidin expression was significantly increased in lung cancer. High hepcidin expression was associated with sex, age, metastasis, and pathological stage and significantly predicted an unfavorable prognosis in lung cancer patients. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Set Enrichment Analysis (GSEA) results suggested that hepcidin is involved in the immune response. Furthermore, hepcidin expression was positively correlated with the infiltration levels of immune cells and the expression of diverse immune cell marker sets. Importantly, hepcidin may affect prognosis partially by regulating immune infiltration in lung cancer patients. Hepcidin may serve as a candidate prognostic biomarker for determining prognosis associated with immune infiltration in lung cancer.

Hydrogen sulfide-induced GAPDH sulfhydration disrupts the CCAR2-SIRT1 interaction to initiate autophagy

The deacetylase SIRT1 (sirtuin 1) has emerged as a major regulator of nucleocytoplasmic distribution of macroautophagy/autophagy marker MAP1LC3/LC3 (microtubule-associated protein 1 light chain 3). Activation of SIRT1 leads to the deacetylation of LC3 and its translocation from the nucleus into the cytoplasm leading to an increase in the autophagy flux. Notably, hydrogen sulfide (H₂S) is a cytoprotective gasotransmitter known to activate SIRT1 and autophagy; however, the underlying mechanism for both remains unknown. Herein, we demonstrate that H₂S sulfhydrates the active site cysteine of the glycolytic enzyme GAPDH (glyceraldehyde-3-phosphate dehydrogenase). Sulfhydration of GAPDH leads to its redistribution into the nucleus. Importantly, nuclear localization of GAPDH is critical for H₂S-mediated activation of autophagy as H₂S does not induce autophagy in cells with GAPDH ablation or cells overexpressing a GAPDH mutant lacking the active site cysteine. Importantly, we observed that nuclear GAPDH interacts with CCAR2/DBC1 (cell cycle activator a nd apoptosis regulator 2) inside the nucleus. CCAR2 interacts with the deacetylase SIRT1 to inhibit its activity. Interaction of GAPDH with CCAR2 disrupts the inhibitory effect of CCAR2 on SIRT1. Activated SIRT1 then deacetylates MAP1LC3B/LC3B (microtubule-associated protein 1 light chain 3 beta) to induce its translocation into the cytoplasm and activate autophagy. Additionally, we demonstrate this pathway's physiological role in autophagy-mediated trafficking of Mycobacterium tuberculosis into lysosomes to restrict intracellular mycobacteria growth. We think that the pathway described here could be involved in H₂S-mediated clearance of intracellular pathogens and other health benefits.Abbreviations: ATG5: autophagy related 5; ATG7: autophagy related 7; BECN1: beclin 1, autophagy related; CCAR2/DBC1: cell cycle activator and apoptosis regulator 2; CFU: colony-forming units; DLG4/PSD95: discs large MAGUK scaffold protein 4; EX-527: 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; H₂S: hydrogen sulfide; HEK: human embryonic kidney cells; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MEF: mouse embryonic fibroblast; Mtb: Mycobacterium tuberculosis; MTOR: mechanistic target of rapamycin kinase; MOI: multiplicity of infection; NO: nitric oxide; PI3K: phosphatidylinositol-4,5-bisphosphate 3-kinase; PLA: proximity ligation assay; PRKAA: protein kinase, AMP-activated, alpha catalytic subunit; SIAH1: siah E3 ubiquitin protein ligase 1A; SIRT1: sirtuin 1; TB: tuberculosis; TP53INP2/DOR: transformation related protein 53 inducible nuclear protein 2; TRP53/TP53: transformation related protein 53.

Pharmacological modulation of the hydrogen sulfide (H2 S) system by dietary H2 S-donors: A novel promising strategy in the prevention and treatment of type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) represents the most common age-related metabolic disorder, and its management is becoming both a health and economic issue worldwide. Moreover, chronic hyperglycemia represents one of the main risk factors for cardiovascular complications. In the last years, the emerging evidence about the role of the endogenous gasotransmitter hydrogen sulfide (H₂ S) in the pathogenesis and progression of T2DM led to increasing interest in the pharmacological modulation of endogenous "H₂ S-system". Indeed, H₂ S directly contributes to the homeostatic maintenance of blood glucose levels; moreover, it improves impaired angiogenesis and endothelial dysfunction under hyperglycemic conditions. Moreover, H₂ S promotes significant antioxidant, anti-inflammatory, and antiapoptotic effects, thus preventing hyperglycemia-induced vascular damage, diabetic nephropathy, and cardiomyopathy. Therefore, H₂ S-releasing molecules represent a promising strategy in both clinical management of T2DM and prevention of macro- and micro-vascular complications associated to hyperglycemia. Recently, growing attention has been focused on dietary organosulfur compounds. Among them, garlic polysulfides and isothiocyanates deriving from Brassicaceae have been recognized as H₂ S-donors of great pharmacological and nutraceutical interest. Therefore, a better understanding of the therapeutic potential of naturally occurring H₂ S-donors may pave the way to a more rational use of these nutraceuticals in the modulation of H₂ S homeostasis in T2DM.

NaSH increases SIRT1 activity and autophagy flux through sulfhydration to protect SH-SY5Y cells induced by MPP~

Parkinson's disease (PD) is one of the most prevailing aging diseases around the world. The present study was to investigate the potential effect of hydrogen sulfide (H2S) and silent mating type information regulation 2 homolog 1 (SIRT1) in MPP~+ induced SH-SY5Y cells and its underlying mechanisms in PD. SH-SY5Y cells were induced by MPP~+ and treated with the H2S donor NaHS to detect the effect of H2S on the molecular behaviors of MPP~+ induced SH-SY5Y cells. NaHS reduced the apoptosis rate and expressions of MDA, 4-HNE and p62, while increased cell viability, autophagy flux and expressions of LC3 II/I and Beclin1 in MPP~+ induced SH-SY5Y cells. Then, levels of autophagy-related proteins and inflammation-related proteins (TNF-α, IL-Iβ) were detected, indicating that Chloroquine and Sirtinol reversed the protective effect of H2S on SH-SY5Y cells induced by MPP~+. We further explored the particular function of H2S, SH-SY5Y cells treated with MPP~+, NaHS chloroquine, and SIRT1 inhibitor (Sirtinol). The results showed that H2S increased SIRT1 expression and sulfhydration. Finally, a PD mouse model verified the above results. In a word, H2S ameliorated SIRT1 activity through acceleration of SIRT1 sulfhydration to increase the autophagy flux and attenuate damage of SH-SY5Y cells induced by MPP~+. H2S and SIRT1 activator might be a target in the treatment of PD patients.

Targeting hydrogen sulphide signaling in breast cancer

Introduction

Hydrogen sulphide (H₂S) has been established as a key member of the gasotransmitters family that recently showed a pivotal role in various pathological conditions including cancer.

Objectives

This study investigated the role of H₂S in breast cancer (BC) pathogenesis, on BC immune recognition capacity and the consequence of targeting H₂S using non-coding RNAs.

Methods

Eighty BC patients have been recruited for the study. BC cell lines were cultured and transfected using validated oligonucleotide delivery system. Gene and protein expression analysis was performed using qRT-PCR, western blot and flow-cytometry. In-vitro analysis for BC hallmarks was performed using MTT, BrdU, Modified Boyden chamber, migration and colony forming assays. H₂S and nitric oxide (NO) levels were measured spectrophotometrically. Primary natural killer cells (NK cells) and T cell isolation and chimeric antigen receptor transduction (CAR T cells) were performed using appropriate kits. NK and T cells cytotoxicity was measured. Finally, computational target prediction analysis and binding confirmation analyses were performed using different software and dual luciferase assay kit, respectively.

Results

The H₂S synthesizing enzymes, cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE), exhibited elevated levels in the clinical samples that correlated with tumor proliferation index. Knock-down of CBS and CSE in the HER2+ BC and triple negative BC (TNBC) cells resulted in significant attenuation of BC malignancy. In addition to increased susceptibility of HER2+ BC and TNBC to the cytotoxic activity of HER2 targeting CAR T cells and NK cells, respectively. Transcriptomic and phosphoprotein analysis revealed that H₂S signaling is mediated through Akt in MCF7, STAT3 in MDA-MB-231 and miR-155/ NOS2/NO signaling in both cell lines. Lastly, miR-4317 was found to function as an upstream regulator of CBS and CSE synergistically abrogates the malignancy of BC cells.

Conclusion

These findings demonstrate the potential role of H₂S signaling in BC pathogenesis and the potential of its targeting for disease mitigation.

WWP2 regulates SIRT1-STAT3 acetylation and phosphorylation involved in hypertensive angiopathy

WWP2 is a HECT‐type E3 ubiquitin ligase that regulates various physiological and pathological activities by binding to different substrates, but its function and regulatory mechanism in vascular smooth muscle cells (VSMCs) are still unknown. Here, we clarified the role of WWP2 in the regulation of SIRT1‐STAT3 and the impact of this regulatory process in VSMCs. We demonstrated that WWP2 expression was significantly increased in angiotensin II‐induced VSMCs model. Knockdown of WWP2 significantly inhibited angiotensin II‐induced VSMCs proliferation, migration and phenotypic transformation, whereas overexpression of WWP2 had opposite effects. In vivo experiments showed that vascular smooth muscle‐specific WWP2 knockout mice significantly relieved angiotensin II‐induced hypertensive angiopathy. Mechanistically, mass spectrometry and co‐immunoprecipitation assays identified that WWP2 is a novel interacting protein of SIRT1 and STAT3. Moreover, WWP2 formed a complex with SIRT1‐STAT3, inhibiting the interaction between SIRT1 and STAT3, then reducing the inhibitory effect of SIRT1 on STAT3, ensuing promoting STAT3‐K685 acetylation and STAT3‐Y705 phosphorylation in angiotensin II‐induced VSMCs and mice. In conclusion, WWP2 modulates hypertensive angiopathy by regulating SIRT1‐STAT3 and WWP2 suppression in VSMCs can alleviate hypertensive angiopathy vitro and vivo. These findings provide new insights into the treatment of hypertensive vascular diseases.

Endogenous hydrogen sulfide improves vascular remodeling through PPARδ/SOCS3 signaling

Introduction

Mounting evidences demonstrated the deficiency of hydrogen sulfide (H₂S) facilitated the progression of cardiovascular diseases. However, the exact effects of H₂S on vascular remodeling are not consistent.

Objectives

This study aimed to investigate the beneficial role of endogenous H₂S on vascular remodeling.

Methods

CSE inhibitor, DL-propargylglycine (PPG) was used to treat mice and vascular smooth muscle cells (VSMCs). Sodium hydrosulfide (NaHS) was given to provide hydrogen sulfide. Vascular tension, H&E staining, masson trichrome staining, western blot and CCK8 were used to determine the vascular remodeling, expressions of inflammatory molecules and proliferation of VSMCs.

Results

The deficiency of endogenous H₂S generated vascular remodeling with aggravated active and passive contraction, thicken aortic walls, collagen deposition, increased phosphorylation of STAT3, decreased production of PPARδ and SOCS3 in aortas, which were reversed by NaHS. PPG inhibited expression of PPARδ and SOCS3, stimulated the phosphorylation of STAT3, increased inflammatory molecules production and proliferation rate of VSMCs which could all be corrected by NaHS supply. PPARδ agonist GW501516 offered protections similar to NaHS in PPG treated VSMCs. Aggravated active and passive contraction in PPG mice aortas, upregulated p-STAT3 and inflammatory molecules, downregulated SOCS3 and phenotype transformation in PPG treated VSMCs could be corrected by PPARδ agonist GW501516 treatment. On the contrary, PPARδ antagonist GSK0660 exhibited opposite effects on vascular contraction in aortas, expressions of p-STAT3 and SOCS3 in VSMCs compared with GW501516.

Conclusion

In a word, endogenous H₂S protected against vascular remodeling through preserving PPARδ/SOCS3 anti-inflammatory signaling pathway. Deficiency of endogenous H₂S should be considered as a risk factor for VSMCs dysfunction.

The Action of JAK/STAT3 and BMP/HJV/SMAD Signaling Pathways on Hepcidin Suppression by Tucum-do-Cerrado in a Normal and Iron-Enriched Diets

The Brazilian savanna fruit, tucum-do-cerrado (Bactris setosa Mart.) reduces hepatic hepcidin levels. Therefore, we investigated the effect of tucum-do-cerrado on the TfR/HFE and/or BMP/HJV/SMAD and JAK/STAT pathways, in normal and excess iron conditions. Rats were treated with: control diet (CT); control diet +15% tucum-do-cerrado (Tuc); iron-enriched diet (+Fe); or iron-enriched diet +15% tucum-do-cerrado (Tuc+Fe). Tucum-do-cerrado (Tuc) decreased hepatic Hamp and Hjv mRNA levels but did not alter Bmp6, Smad7, Tfr1, and Hfe mRNA levels; pSMAD1/5/8 and pSTAT3 protein levels; labile iron pool (LIP); and inflammatory biomarkers, compared to the CT group. The iron-enriched diet increased Hamp mRNA levels, as well as pSMAD1/5/8 and pSTAT3 protein levels, while no difference was observed in Hjv, Bmp6, Smad7, Tfr1, and Hfe mRNA levels and LIP compared to the CT group. The association of tucum-do-cerrado with the iron-enriched diet (Tuc+Fe) decreased Hamp, Hjv, Bmp6, and Hfe mRNA levels and pSTAT3 protein content compared to the +Fe group, while increased Hamp and decreased Hfe mRNA levels compared to the Tuc group. Therefore, the inhibition of hepatic hepcidin by tucum-do-cerrado consumption may involve the downregulation of intestinal Dmt1 and hepatic Hjv expression and deacetylation mediated by SIRT1 by a mechanism that is independent of tissue iron content. However, in excess iron conditions, the modulation of hepatic hepcidin expression by tucum-do-cerrado seems to be partially mediated by the inflammatory signaling pathway, as well as involves the chelating activity of tucum-do-cerrado.

Xuesaitong May Protect Against Ischemic Stroke by Modulating Microglial Phenotypes and Inhibiting Neuronal Cell Apoptosis via the STAT3 Signaling Pathway

BACKGROUND

Xuesaitong mainly comprises Panax notoginseng saponins and has shown a promising feature in an acute ischemic stroke model; however, its effect on long-term recovery following stroke, and the related mechanisms, are unknown.

METHODS

The objective of this study was to investigate the long-term protective effects of xuesaitong against ischemic stroke and its effect on microglial polarization. Experimental cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) for 45 min, and C57BL/6 mice were immediately injected with xuesaitong or vehicle through the caudal vein at the onset of cerebral reperfusion consecutively for 14 days. The animals were randomly divided into three groups: a sham-operated group, vehicle-treated group and xuesaitong-treated group at a dose of 15μg/g. Subsequently, 2,3,5-triphenyltetrazolium chloride staining was used to assess infarct volume, and adhesive removal tests and balance beam tests were used to evaluate neurological deficits at days 1, 3, 7 and 14 following ischemia. Reverse-transcriptase polymerase chain reaction and immunofluorescence staining for M1 markers (CD16, iNOS) and M2 markers (CD206, arginase-1) were performed to characterize phenotypic changes in microglia. Elisa was used to determine the release of pro-inflammatory and anti-inflammatory cytokines. TUNEL staining was conducted to detect neuronal cell apoptosis, and western blots were used to determine the activation of signal transducer and activator of transcription 3 (STAT3).

RESULTS

Our results revealed that xuesaitong treatment, compared with vehicle treatment, significantly reduced cerebral infarct volume 1 and 3 days after MCAO and resulted in significant improvements in long-term neurological outcomes. Furthermore, xuesaitong treatment, compared with vehicle treatment, significantly reduced M1 markers and elevated M2 markers 7 and 14 days after MCAO at both the mRNA and protein level in ipsilateral brain tissue. This finding was also accompanied by a reduction in neuronal cell apoptosis and p-STAT3 transcription factor levels in the xuesaitong-treated group compared with the vehicle-treated group.

CONCLUSION

We demonstrated that xuesaitong has long-term neuroprotective effects against ischemic stroke, possibly by promoting the polarization of microglia to an M2 phenotype and by inhibiting neuronal cell death via down-regulation of the STAT3 signaling pathway, providing new evidence that xuesaitong might be a promising therapeutic strategy for ischemic stroke.

A Novel Rhynchophylline Analog, Y396, Inhibits Endothelial Dysfunction Induced by Oxidative Stress in Diabetes Through Epidermal Growth Factor Receptor

Aims: Endothelial dysfunction appears in early diabetes mellitus partially because of epidermal growth factor receptor (EGFR) abnormal activation and downstream oxidative stress. The aim of this study was to determine whether Y396, a synthesized analog of rhynchophylline, could protect against endothelial dysfunction in diabetes and the underlying molecular mechanism. Results: Y396 could directly target the EGFR and inhibit its phosphorylation induced by high glucose and EGF, downstream translocation to the nucleus of E2F1, and its transcriptional activity and expression of Nox4. Diabetes-induced endothelium malfunction was ameliorated by Y396 treatment through EGFR inhibition. Downstream oxidative stress was decreased by Y396 in the aortas of type 1 diabetes mellitus mice and primary rat aorta endothelial cells (RAECs). Y396 could also ameliorate tunicamycin-induced oxidative stress in the aorta and RAECs. In addition, we again determined the protective effects of Y396 on high-fat diet/streptozotocin-induced type 2 diabetes mellitus. Innovation: This is the first study to demonstrate that Y396, a novel rhynchophylline analog, suppressed high-glucose-induced endothelial malfunction both in vivo and in vitro by inhibiting abnormal phosphorylation of EGFR. Our work uncovered EGFR as a novel therapeutic target and Y396 as a potential therapy against diabetes-induced complication. Conclusion: Y396 could directly bind with EGFR, and inhibit its phosphorylation and downstream E2F1 transcriptional activity. It could also preserve tunicamycin-evoked endothelial dysfunction and oxidative stress. It could protect against diabetes-induced endothelium malfunction in vivo through EGFR inhibition and downstream oxidative stress. Antioxid. Redox Signal. 32, 743-765.

Septin4 Prevents PDGF-BB-induced HAVSMC Phenotypic Transformation, Proliferation and Migration by Promoting SIRT1-STAT3 Deacetylation and Dephosphorylation

SIRT1 and STAT3 are key to human aortic vascular smooth muscle cells (HAVSMCs) proliferation, migration and phenotypic transformation, but the regulatory mechanism of SIRT1-STAT3 in this process is still unclear. Septin4 is a cytoskeleton-related protein that regulates oxidative stress-vascular endothelial injury. However, the role and underlying mechanism of Septin4 in atherosclerosis remains unknown. Here, we revealed the role and mechanism of Septin4 in regulating SIRT1-STAT3 in atherosclerosis. We determined that the expression of Septin4 were markedly increased in Apoe^-/- atherosclerosis mice and PDGF-BB-induced HAVSMCs. Knockdown of Septin4 significantly increased PDGF-BB-induced HAVSMCs proliferation, migration and phenotypic transformation, while overexpression of Septin4 had the opposite effects. Mechanically, co-immunoprecipitation results demonstrated that Septin4 was a novel interacting protein of STAT3 and SIRT1. Septin4 formed a complex with SIRT1-STAT3, enhancing the interaction between SIRT1 and STAT3, ensuing promoting SIRT1-regulated STAT3-K685 deacetylation and STAT3-Y705 dephosphorylation, which inhibited PDGF-BB-induced HAVSMCs proliferation, migration and phenotype transformation. Therefore, our findings provide novel insights into the prevention and treatment of atherosclerosis.

A Novel Liposomal S-Propargyl-Cysteine: A Sustained Release of Hydrogen Sulfide Reducing Myocardial Fibrosis via TGF-β1/Smad Pathway

Purpose

S-propargyl-cysteine (SPRC; alternatively known as ZYZ-802) is a novel modulator of endogenous tissue H₂S concentrations with known cardioprotective and anti-inflammatory effects. However, its rapid metabolism and excretion have limited its clinical application. To overcome these issues, we have developed some novel liposomal carriers to deliver ZYZ-802 to cells and tissues and have characterized their physicochemical, morphological and pharmacological properties.

Methods

Two liposomal formulations of ZYZ-802 were prepared by thin-layer hydration and the morphological characteristics of each liposome system were assessed using a laser particle size analyzer and transmission electron microscopy. The entrapment efficiency and ZYZ-802 release profiles were determined following ultrafiltration centrifugation, dialysis tube and HPLC measurements. LC-MS/MS was used to evaluate the pharmacokinetic parameters and tissue distribution profiles of each formulation via the measurements of plasma and tissues ZYZ-802 and H₂S concentrations. Using an in vivo model of heart failure (HF), the cardio-protective effects of liposomal carrier were determined by echocardiography, histopathology, Western blot and the assessment of antioxidant and myocardial fibrosis markers.

Results

Both liposomal formulations improved ZYZ-802 pharmacokinetics and optimized H₂S concentrations in plasma and tissues. Liposomal ZYZ-802 showed enhanced cardioprotective effects in vivo. Importantly, liposomal ZYZ-802 could inhibit myocardial fibrosis via the inhibition of the TGF-β1/Smad signaling pathway.

Conclusion

The liposomal formulations of ZYZ-802 have enhanced pharmacokinetic and pharmacological properties in vivo. This work is the first report to describe the development of liposomal formulations to improve the sustained release of H₂S within tissues.

Anti-TNF-α Monoclonal Antibody Therapy Improves Anemia through Downregulating Hepatocyte Hepcidin Expression in Inflammatory Bowel Disease

Anemia is one of the most common complications in patients with inflammatory bowel disease (IBD). Hepcidin as a key regulator of iron metabolism is pivotal in mediating the occurrence of anemia of chronic disease. Herein, we analyzed the levels of hepcidin in sera from IBD patients by enzyme-linked immunosorbent assay and investigated its potential role in regulating the anemia in IBD. We observed that the levels of serum hepcidin were increased in active IBD patients compared with those in remitted IBD patients and healthy controls and that serum hepcidin was associated with disease activity, CRP, and ESR, respectively. Importantly, we found that the increased levels of serum hepcidin were positively correlated with the severity of anemia and the imbalance of iron metabolism in anemic UC and CD patients. Proinflammatory factors (e.g., IL-6, IL-17, and TNF-α) were positively correlated with the concentrations of serum hepcidin in IBD patients. Interestingly, hepcidin was found to be decreased in patients with Crohn's disease after successful therapy with anti-TNF-α mAb (i.e., infliximab), indicating the underlying association between TNF-α and hepcidin expression. To investigate the specific mechanisms involved, we cultured LO2 and HepG2 cell lines in vitro under stimulation with TNF-α and observed that the levels of hepcidin mRNA were markedly upregulated in caspase-3/8- and NF-κB-dependent manners. Therefore, our data suggest that TNF-α stimulates the expression of hepcidin in IBD patients, resulting in aggravated anemia and that blockage of TNF-α or the caspase-3/8 and NF-κB pathways could downregulate hepcidin expression. This study provides inspiration for the therapy and management of anemia in IBD.

An Update on the Multifaceted Roles of STAT3 in the Heart

Signal transducer and activator of transcription 3 (STAT3) is a signaling molecule and transcription factor that plays important protective roles in the heart. The protection mediated by STAT3 is attributed to its genomic actions as a transcription factor and other non-genomic roles targeting mitochondrial function and autophagy. As a transcription factor, STAT3 upregulates genes that are anti-oxidative, anti-apoptotic, and pro-angiogenic, but suppresses anti-inflammatory and anti-fibrotic genes. Its suppressive effects on gene expression are achieved through competing with other transcription factors or cofactors. STAT3 is also linked to the modification of mRNA expression profiles in cardiac cells by inhibiting or inducing miRNA. In addition to these genomic roles, STAT3 is suggested to function protectively in mitochondria, where it regulates ROS production, in part by regulating the activities of the electron transport chain complexes, although our recent evidence calls this role into question. Nonetheless, STAT3 is a key player known to be activated in the cardioprotective ischemic conditioning protocols. Through these varied roles, STAT3 participates in various mechanisms that contribute to cardioprotection against different heart pathologies, including myocardial infarction, hypertrophy, diabetic cardiomyopathy, and peripartum cardiomyopathy. Understanding how STAT3 is involved in the protective mechanisms against these different cardiac pathologies could lead to novel therapeutic strategies to treat them.

Exogenous H2S reduces the acetylation levels of mitochondrial respiratory enzymes via regulating the NAD+-SIRT3 pathway in cardiac tissues of db/db mice

Hydrogen sulfide (H₂S), a gaseous molecule, is involved in modulating multiple physiological functions, such as antioxidant, antihypertension, and the production of polysulfide cysteine. H₂S may inhibit reactive oxygen species generation and ATP production through modulating respiratory chain enzyme activities; however, the mechanism of this effect remains unclear. In this study, db/db mice, neonatal rat cardiomyocytes, and H9c2 cells treated with high glucose, oleate, and palmitate were used as animal and cellular models of type 2 diabetes. The mitochondrial respiratory rate, respiratory chain complex activities, and ATP production were decreased in db/db mice compared with those in db/db mice treated with exogenous H₂S. Liquid chromatography with tandem mass spectrometry analysis showed that the acetylation level of proteins involved in the mitochondrial respiratory chain were increased in the db/db mice hearts compared with those with sodium hydrosulfide (NaHS) treatment. Exogenous H₂S restored the ratio of NAD⁺/NADH, enhanced the expression and activity of sirtuin 3 (SIRT3) and decreased mitochondrial acetylation level in cardiomyocytes under hyperglycemia and hyperlipidemia. As a result of SIRT3 activation, acetylation of the respiratory complexe enzymes NADH dehydrogenase 1 (ND1), ubiquinol cytochrome c reductase core protein 1, and ATP synthase mitochondrial F1 complex assembly factor 1 was reduced, which enhanced the activities of the mitochondrial respiratory chain activity and ATP production. We conclude that exogenous H₂S plays a critical role in improving cardiac mitochondrial function in diabetes by upregulating SIRT3.

Secukinumab attenuates reactive astrogliosis via IL-17RA/(C/EBPβ)/SIRT1 pathway in a rat model of germinal matrix hemorrhage

Aims

Reactive astrogliosis plays a critical role in neurological deficits after germinal matrix hemorrhage (GMH). It has been reported that interleukin‐17A and IL‐17A receptor IL‐17RA/(C/EBPβ)/SIRT1 signaling pathway enhances reactive astrogliosis after brain injuries. We evaluated the effects of secukinumab on reactive astrogliosis in a rat pup model of GMH.

Methods

A total of 146 Sprague Dawley P7 rat pups were used. GMH was induced by intraparenchymal injection of collagenase. Secukinumab was administered intranasally 1 hour post‐GMH. C/EBPβ CRISPR or SIRT1 antagonist EX527 was administrated intracerebroventricularly (icv) 48 hours and 1 hour before GMH induction, respectively. Neurobehavior, Western blot, histology, and immunohistochemistry were used to assess treatment regiments in the short term and long term.

Results

The endogenous IL‐17A, IL‐17RA, C/EBPβ, and GFAP and proliferation marker CyclinD1 were increased, while SIRT1 expression was decreased after GMH. Secukinumab treatment improved neurological deficits, reduced ventriculomegaly, and increased cortical thickness. Additionally, treatment increased SIRT1 expression and lowered proliferation proteins PCNA and CyclinD1 as well as GFAP expression. C/EBPβ CRISPR activation plasmid and EX527 reversed the antireactive astrogliosis effects of secukinumab.

Conclusion

Secukinumab attenuated reactive astrogliosis and reduced neurological deficits after GMH, partly by regulating IL‐17RA/(C/EBPβ)/SIRT1 pathways. Secukinumab may provide a promising therapeutic strategy for GMH patients.

The Role of Metabolic Remodeling in Macrophage Polarization and Its Effect on Skeletal Muscle Regeneration

Significance: Macrophages are crucial for tissue homeostasis. Based on their activation, they might display classical/M1 or alternative/M2 phenotypes. M1 macrophages produce pro-inflammatory cytokines, reactive oxygen species (ROS), and nitric oxide (NO). M2 macrophages upregulate arginase-1 and reduce NO and ROS levels; they also release anti-inflammatory cytokines, growth factors, and polyamines, thus promoting angiogenesis and tissue healing. Moreover, M1 and M2 display key metabolic differences; M1 polarization is characterized by an enhancement in glycolysis and in the pentose phosphate pathway (PPP) along with a decreased oxidative phosphorylation (OxPhos), whereas M2 are characterized by an efficient OxPhos and reduced PPP. Recent Advances: The glutamine-related metabolism has been discovered as crucial for M2 polarization. Vice versa, flux discontinuities in the Krebs cycle are considered additional M1 features; they lead to increased levels of immunoresponsive gene 1 and itaconic acid, to isocitrate dehydrogenase 1-downregulation and to succinate, citrate, and isocitrate over-expression. Critical Issues: A macrophage classification problem, particularly in vivo, originating from a gap in the knowledge of the several intermediate polarization statuses between the M1 and M2 extremes, characterizes this field. Moreover, the detailed features of metabolic reprogramming crucial for macrophage polarization are largely unknown; in particular, the role of β-oxidation is highly controversial. Future Directions: Manipulating the metabolism to redirect macrophage polarization might be useful in various pathologies, including an efficient skeletal muscle regeneration. Unraveling the complexity pertaining to metabolic signatures that are specific for the different macrophage subsets is crucial for identifying new compounds that are able to trigger macrophage polarization and that might be used for therapeutical purposes.

H2S promotes proliferation of endometrial stromal cells via activating the NF-κB pathway in endometriosis

Hydrogen sulfide (H₂S) is substantially converted from cysteine by the enzymes cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE). H₂S can profoundly affect most organ systems in animals and humans by inducing a wide range of physiological functions. However, the roles of H₂S in the progression of endometriosis remain unknown. The aim of the current study was to test the hypothesis that H₂S might play a role in the pathogenesis of endometriosis via modulating the biological behavior of endometrial stromal cells (ESCs). First, we explored the expression level of CBS and CSE in ESCs via immunohistochemistry and immunocytochemistry. Second, cell Count Kit-8 (CCK-8) assays were utilized to investigate the cell viability of human ESCs (HESCs) in vitro. Third, we studied the potential effects of H₂S in a rodent model of endometriosis. Both CBS and CSE were overexpressed in endometriotic lesions. Exogenous and endogenous H₂S could promote HESC proliferation in vitro. Furthermore, this pro-proliferation effect could be reversed by treating with inhibitors of CBS, CSE, or the NF-κB pathway. In vivo, we uncovered that inhibitors of CBS and CSE could remarkably reduce the number and weight of mouse endometriotic lesions. These data suggested that H₂S promotes ESC proliferation via activation of the NF-κB pathway, which provides a scientific basis for the clinical application of blocking H₂S to treat endometriosis.

Novel Liposome Eencapsulated Guanosine Di Phosphate based Therapeutic Target against Anemia of Inflammation

Hepcidin, master regulator of iron homeostasis, causes anemia under infectious and inflammatory conditions by reducing intestinal absorption of iron with decreased release of iron from macrophages and liver despite adequate iron stores leading to Anemia of Inflammation (AI). Many therapeutic trials have been carried out but none have been effective due to its adverse effects. In present study, we discover that Guanosine 5'-diphosphate (GDP) encapsulated in lipid vesicle (NH+) was found to inhibit NF-ҝB activation by limiting phosphorylation and degradation of IҝBα, thus, attenuating IL-6 secretion from macrophage cells. Moreover, the suppressed IL-6 levels down regulated JAK2/STAT3 pathway with decrease inflammation-mediated Hamp mRNA transcription (HepG2) and increase iron absorption (Caco2) in HepG2/Caco2 co-culture model. Analogous results were obtained in acute and chronic AI mice model thus, correcting haemoglobin level. These results proved NH + GDP as novel therapeutic agent to overcome limitations and suggests it as potential drug to ameliorate AI.

Hepcidin Therapeutics

Hepcidin is a key hormonal regulator of systemic iron homeostasis and its expression is induced by iron or inflammatory stimuli. Genetic defects in iron signaling to hepcidin lead to “hepcidinopathies” ranging from hereditary hemochromatosis to iron-refractory iron deficiency anemia, which are disorders caused by hepcidin deficiency or excess, respectively. Moreover, dysregulation of hepcidin is a pathogenic cofactor in iron-loading anemias with ineffective erythropoiesis and in anemia of inflammation. Experiments with preclinical animal models provided evidence that restoration of appropriate hepcidin levels can be used for the treatment of these conditions. This fueled the rapidly growing field of hepcidin therapeutics. Several hepcidin agonists and antagonists, as well as inducers and inhibitors of hepcidin expression have been identified to date. Some of them were further developed and are currently being evaluated in clinical trials. This review summarizes the state of the art.