Digoxin improves steatohepatitis with differential involvement of liver cell subsets in mice through inhibition of PKM2 transactivation

Toxicarioside H-mediated modulation of the immune microenvironment attenuates ovalbumin-induced allergic airway inflammation by inhibiting NETosis

PURPOSE

Our team identified a new cardiac glycoside, Toxicarioside H (ToxH), in a tropical plant. Previous research has indicated the potential of cardenolides in mitigating inflammation, particularly in the context of NETosis. Therefore, this study sought to examine the potential of ToxH in attenuating allergic airway inflammation by influencing the immune microenvironment.

METHODS

An OVA-induced airway inflammation model was established in BALB/c mice. After the experiment was completed, serum, bronchoalveolar lavage fluid (BALF), and lung tissue samples were collected and further examined using H&E and PAS staining, flow cytometry, immunofluorescence observation, and Western blot analysis.

RESULTS

Treatment with ToxH was found to be effective in reducing airway inflammation and mucus production. This was accompanied by an increase in Th1 cytokines (IFN-γ, IL-2, and TNF-β), and the Th17 cytokine IL-17, while levels of Th2 cytokines (IL-4, IL-5, and IL-13) and Treg cytokines (IL-10 and TGF-β1) were decreased in both the bronchoalveolar lavage fluid (BALF) and the CD45+ immune cells in the lungs. Additionally, ToxH inhibited the infiltration of inflammatory cells and decreased the number of pulmonary CD44+ memory T cells, while augmenting the numbers of Th17 and Treg cells. Furthermore, the neutrophil elastase inhibitor GW311616A was observed to suppress airway inflammation and mucus production, as well as alter the secretion of immune Th1, Th2, Th17, and Treg cytokines in the lung CD45+ immune cells. Moreover, our study also demonstrated that treatment with ToxH efficiently inhibited ROS generation, thereby rectifying the dysregulation of immune cells in the immune microenvironment in OVA-induced allergic asthma.

CONCLUSIONS

Our findings indicate that ToxH could serve as a promising therapeutic intervention for allergic airway inflammation and various other inflammatory disorders. Modulating the balance of Th1/Th2 and Treg/Th17 cells within the pulmonary immune microenvironment may offer an effective strategy for controlling allergic airway inflammation.

Novel insights into macrophage immunometabolism in nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH), an inflammatory subtype of nonalcoholic fatty liver disease (NAFLD), is characterized by liver steatosis, inflammation, hepatocellular injury and different degrees of fibrosis, and has been becoming the leading cause of liver-related morbidity and mortality worldwide. Unfortunately, the pathogenesis of NASH has not been completely clarified, and there are no approved therapeutic drugs. Recent accumulated evidences have revealed the involvement of macrophage in the regulation of host liver steatosis, inflammation and fibrosis, and different phenotypes of macrophages have different metabolic characteristics. Therefore, targeted regulation of macrophage immunometabolism may contribute to the treatment and prognosis of NASH. In this review, we summarized the current evidences of the role of macrophage immunometabolism in NASH, especially focused on the related function conversion, as well as the strategies to promote its polarization balance in the liver, and hold promise for macrophage immunometabolism-targeted therapies in the treatment of NASH.

The impact of obstructive sleep apnea on nonalcoholic fatty liver disease

Obstructive sleep apnea (OSA) is characterized by episodic sleep state-dependent collapse of the upper airway, with consequent hypoxia, hypercapnia, and arousal from sleep. OSA contributes to multisystem damage; in severe cases, sudden cardiac death might occur. In addition to causing respiratory, cardiovascular and endocrine metabolic diseases, OSA is also closely associated with nonalcoholic fatty liver disease (NAFLD). As the prevalence of OSA and NAFLD increases rapidly, they significantly exert adverse effects on the health of human beings. The authors retrieved relevant documents on OSA and NAFLD from PubMed and Medline. This narrative review elaborates on the current knowledge of OSA and NAFLD, demonstrates the impact of OSA on NAFLD, and clarifies the underlying mechanisms of OSA in the progression of NAFLD. Although there is a lack of sufficient high-quality clinical studies to prove the causal or concomitant relationship between OSA and NAFLD, existing evidence has confirmed the effect of OSA on NAFLD. Elucidating the underlying mechanisms through which OSA impacts NAFLD would hold considerable importance in terms of both prevention and the identification of potential therapeutic targets for NAFLD.

Glycolysis in Chronic Liver Diseases: Mechanistic Insights and Therapeutic Opportunities

Chronic liver diseases (CLDs) cover a spectrum of liver diseases, ranging from nonalcoholic fatty liver disease to liver cancer, representing a growing epidemic worldwide with high unmet medical needs. Glycolysis is a conservative and rigorous process that converts glucose into pyruvate and sustains cells with the energy and intermediate products required for diverse biological activities. However, abnormalities in glycolytic flux during CLD development accelerate the disease progression. Aerobic glycolysis is a hallmark of liver cancer and is responsible for a broad range of oncogenic functions including proliferation, invasion, metastasis, angiogenesis, immune escape, and drug resistance. Recently, the non-neoplastic role of aerobic glycolysis in immune activation and inflammatory disorders, especially CLD, has attracted increasing attention. Several key mediators of aerobic glycolysis, including HIF-1α and pyruvate kinase M2 (PKM2), are upregulated during steatohepatitis and liver fibrosis. The pharmacological inhibition or ablation of PKM2 effectively attenuates hepatic inflammation and CLD progression. In this review, we particularly focused on the glycolytic and non-glycolytic roles of PKM2 in the progression of CLD, highlighting the translational potential of a glycolysis-centric therapeutic approach in combating CLD.

Digoxin as an emerging therapy in noncardiac diseases

The cardiac glycoside (CG) digoxin is a generic drug approved for the treatment of heart failure and supraventricular arrhythmias. Over the past few decades, substantial strides have been made toward repurposing digoxin to treat various noncardiac diseases. Here, we evaluate recent insights into basic and clinical work related to noncardiac use of digoxin.

New uses for an old remedy: Digoxin as a potential treatment for steatohepatitis and other disorders

Repurposing of the widely available and relatively cheap generic cardiac gly-coside digoxin for non-cardiac indications could have a wide-ranging impact on the global burden of several diseases. Over the past several years, there have been significant advances in the study of digoxin pharmacology and its potential non-cardiac clinical applications, including anti-inflammatory, antineoplastic, metabolic, and antimicrobial use. Digoxin holds promise in the treatment of gastrointestinal disease, including nonalcoholic steatohepatitis and alcohol-associated steatohepatitis as well as in obesity, cancer, and treatment of viral infections, among other conditions. In this review, we provide a summary of the clinical uses of digoxin to date and discuss recent research on its emerging applications.

The role of hypoxia-inducible factor 1α in hepatic lipid metabolism

Chronic liver disease is a major public health problem with a high and increasing prevalence worldwide. In the progression of chronic liver disease, steatosis drives the progression of the disease to cirrhosis or even liver cancer. Hypoxia-inducible factor 1α (HIF-1α) is central to the regulation of hepatic lipid metabolism. HIF-1α upregulates the expression of genes related to lipid uptake and synthesis in the liver and downregulates the expression of lipid oxidation genes. Thus, it promotes intrahepatic lipid deposition. In addition, HIF-1α is expressed in white adipose tissue, where lipolysis releases free fatty acids (FFAs) into the blood. These circulating FFAs are taken up by the liver and accumulate in the liver. The expression of HIF-1α in the liver condenses bile and makes it easier to form gallstones. Contrary to the role of hepatic HIF-1α, intestinal HIF-1α expression can maintain a healthy microbiota and intestinal barrier. Thus, it plays a protective role against hepatic steatosis. This article aims to provide an overview of the current understanding of the role of HIF-1α in hepatic steatosis and to encourage the development of therapeutic agents associated with HIF-1α pathways. KEY MESSAGES: • Hepatic HIF-1α expression promotes lipid uptake and synthesis and reduces lipid oxidation leading to hepatic steatosis. • The expression of HIF-1α in the liver condenses bile and makes it easier to form gallstones. • Intestinal HIF-1α expression can maintain a healthy microbiota and intestinal barrier.

Targeting macrophage polarization as a promising therapeutic strategy for the treatment of osteoarthritis

Osteoarthritis (OA) is a chronic osteoarthropathy characterized by the progressive degeneration of articular cartilage and synovial inflammation. Early OA clinical treatments involve intra-articular injection of glucocorticoids, oral acetaminophen and non-steroidal anti-inflammatory drugs (NSAIDs), which are used for anti-inflammation and pain relief. However, long-term use of these agents will lead to inevitable side effects, even aggravate cartilage loss. At present, there are no disease-modifying OA drugs (DMOADs) yet approved by regulatory agencies. Polarization regulation of synovial macrophages is a new target for OA treatment. Inhibiting M1 polarization and promoting M2 polarization of synovial macrophages can alleviate synovial inflammation, relieve joint pain and inhibit articular cartilage degradation, which is a promising strategy for OA treatment. In this study, we describe the molecular mechanisms of macrophage polarization and its key role in the development of OA. Subsequently, we summarize the latest progress of strategies for OA treatment through macrophage reprogramming, including small molecule compounds (conventional western medicine and synthetic compounds, monomer compounds of traditional Chinese medicine), biomacromolecules, metal/metal oxides, cells, and cell derivatives, and interprets the molecular mechanisms, hoping to provide some information for DMOADs development.

iNKT17 cells play a pathogenic role in ethinylestradiol-induced cholestatic hepatotoxicity

IL-17 is closely associated with inflammation in intrahepatic cholestasis (IHC). Targeting IL-17 ameliorates IHC in mice. Invariant natural killer T (iNKT) cells are predominantly enriched in the liver and they mediate drug-induced liver injury through their secreted cytokines. However, whether iNKT17 cells are involved in ethinylestradiol (EE)-induced IHC remains unclear. In the present study, the administration of EE (10 mg/kg in vivo and 6.25 μM in vitro) promoted the activation and expansion of iNKT17 cells, which contributed to a novel hepatic iNKT17/Treg imbalance. iNKT cell-deficient Jα18^-/- mice and the RORγt inhibitor digoxin (20 μg) alleviated EE-induced cholestatic hepatotoxicity and downregulated the IL-17 signalling pathway. In contrast, the co-administration of EE with recombinant IL-17 (1 μg) to Jα18^-/- mice induced cholestatic hepatotoxicity and increased the infiltration of hepatic neutrophils and monocytes. Importantly, the administration of IL-17^-/- iNKT cells (3.5 × 10⁵) to Jα18^-/- mice resulted in the attenuation of hepatotoxicity and the recruitment of fewer hepatic neutrophils and monocytes than the adoptive transfer of wild-type iNKT cells. These results indicated that iNKT17 cells could exert pathogenic effects. The recruitment and activation of iNKT17 cells could be attributed to the high level of CXCR3 expression on their surface. CXCL10 deficiency ameliorated EE-induced cholestatic liver damage, reduced hepatic CXCR3⁺ iNKT cells and inhibited RORγt expression. These findings suggest that iNKT17 cells play a key role in EE-induced cholestatic liver injury via CXCR3-mediated recruitment and activation. Our study provides new insights and therapeutic targets for cholestatic diseases.

Prospective clinical trials and novel therapies in the medical management of severe alcohol-associated hepatitis

Content available: Author Interview and Audio Recording.

GSK3β mediates the spatiotemporal dynamics of NLRP3 inflammasome activation

Subcellular machinery of NLRP3 is essential for inflammasome assembly and activation. However, the stepwise process and mechanistic basis of NLRP3 engagement with organelles remain unclear. Herein, we demonstrated glycogen synthase kinase 3β (GSK3β) as a molecular determinant for the spatiotemporal dynamics of NLRP3 inflammasome activation. Using live cell multispectral time-lapse tracking acquisition, we observed that upon stimuli NLRP3 was transiently associated with mitochondria and subsequently recruited to the Golgi network (TGN) where it was retained for inflammasome assembly. This occurred in relation to the temporal contact of mitochondria to Golgi apparatus. NLRP3 stimuli initiate GSK3β activation with subsequent binding to NLRP3, facilitating NLRP3 recruitment to mitochondria and transition to TGN. GSK3β activation also phosphorylates phosphatidylinositol 4-kinase 2 Α (PI4k2A) in TGN to promote sustained NLRP3 oligomerization. Our study has identified the interplay between GSK3β signaling and the organelles dynamics of NLRP3 required for inflammasome activation and opens new avenues for therapeutic intervention.

Digoxin ameliorates joint inflammatory microenvironment by downregulating synovial macrophage M1-like-polarization and its-derived exosomal miR-146b-5p/Usp3&Sox5 axis

Relatively low-grade inflammatory of osteoarthritic joints is characterized by synovitis and a catabolic and proinflammatory state of the chondrocytes and plays an important role in osteoarthritis (OA) initiation and exacerbation. Our previous research showed cardiac glycoside compounds might be effective in OA synovitis. However, the effect of digoxin (DIG), an FDA-approved cardenolide, on inflammation inhibition of osteoarthritic joints has not been investigated. In the present study, a western blot analysis and immunofluorescence staining revealed that DIG alleviated OA synovitis by inhibiting the M1-like polarization of synovial macrophages in OA patients and collagenase-induced OA (CIOA, with considerable synovitis) mice. Subsequently, the exosomes produced by macrophages and M1-like macrophages treated with or without DIG were isolated and identified. According to miRNA sequencing analysis of these exosomes and subsequent target activity assays, we confirmed DIG controls OA inflammatory microenvironment and promotes chondrogenesis by, at least partly, downregulating the M1-like macrophage-derived exosomal miR-146b-5p/Usp3&Sox5 axis in vitro and in vivo. This research provides reliable experimental evidence supporting the clinical application of DIG as a disease-modifying drug for inflammation-associated OA. Additionally, the spectrum of diseases of inflammation controlled by DIG has been broadened, which prompting research interest in the new function of an "old" FDA-approved drug.

Immune and Metabolic Alterations in Liver Fibrosis: A Disruption of Oxygen Homeostasis?

According to the WHO, “cirrhosis of the liver” was the 11th leading cause of death globally in 2019. Many kinds of liver diseases can develop into liver cirrhosis, and liver fibrosis is the main pathological presentation of different aetiologies, including toxic damage, viral infection, and metabolic and genetic diseases. It is characterized by excessive synthesis and decreased decomposition of extracellular matrix (ECM). Hepatocyte cell death, hepatic stellate cell (HSC) activation, and inflammation are crucial incidences of liver fibrosis. The process of fibrosis is also closely related to metabolic and immune disorders, which are usually induced by the destruction of oxygen homeostasis, including mitochondrial dysfunction, oxidative stress, and hypoxia pathway activation. Mitochondria are important organelles in energy generation and metabolism. Hypoxia-inducible factors (HIFs) are key factors activated when hypoxia occurs. Both are considered essential factors of liver fibrosis. In this review, the authors highlight the impact of oxygen imbalance on metabolism and immunity in liver fibrosis as well as potential novel targets for antifibrotic therapies.

A Perspective on Medicinal Chemistry Approaches for Targeting Pyruvate Kinase M2

The allosteric regulation of pyruvate kinase M2 (PKM2) affects the switching of the PKM2 protein between the high-activity and low-activity states that allow ATP and lactate production, respectively. PKM2, in its low catalytic state (dimeric form), is chiefly active in metabolically energetic cells, including cancer cells. More recently, PKM2 has emerged as an attractive target due to its role in metabolic dysfunction and other interrelated conditions. PKM2 (dimer) activity can be inhibited by modulating PKM2 dimer-tetramer dynamics using either PKM2 inhibitors that bind at the ATP binding active site of PKM2 (dimer) or PKM2 activators that bind at the allosteric site of PKM2, thus activating PKM2 from the dimer formation to the tetrameric formation. The present perspective focuses on medicinal chemistry approaches to design and discover PKM2 inhibitors and activators and further provides a scope for the future design of compounds targeting PKM2 with better efficacy and selectivity.

Digoxin mitigates diethylnitrosamine-induced acute liver injury in mice via limiting production of inflammatory mediators

The cardiotonic digoxin has been recently shown to possess an anti-inflammatory potential in numerous metabolic and inflammatory disorders. However, data about digoxin’s impact in the setting of acute liver injury and sterile inflammation are still limited. Here, we investigated the potential effect of digoxin pretreatments (0.25 and 0.5 mg/kg, oral) on the severity of acute hepatotoxicity in mice challenged with a single dose of diethylnitrosamine (DN; 150 mg/kg, intraperitoneal) for 24 h. Our results indicated that digoxin pretreatments dose-dependently mitigated DN-induced rise of hepatocellular injury parameters and necroinflammation scores. Digoxin, particularly at dose of 0.5 mg/kg, boosted the number of PCNA positive hepatocytes, leading to improvement of the reparative potential in hepatocytes of DN-intoxicated livers. Digoxin’s ameliorative effect on DN-hepatotoxicity coincided with (i) lowering the increased hepatic production and release of the proinflammatory mediators IL-17A, IL-1β and TNF-α, and (ii) impeding the attraction and infiltration of monocytes to the liver, as denoted by decreasing serum MCP-1 and F4/80 immunohistochemical expression. These effects were attributed to reducing DN-induced activation of NF-κB and overexpression of CD98 in the liver. Meanwhile, DN elicited a decline in the hepatic production and release of the anti-inflammatory cytokines IL-22 and IL-6, which was intensified by digoxin, especially at a dose 0.5 mg/kg. In conclusion, digoxin conferred liver protection against DN-insult by impairing the overproduction of proinflammatory cytokines and infiltration of inflammatory cells to the liver.

A digital pathology tool for quantification of color features in histologic specimens

In preclinical research, histological analysis of tissue samples is often limited to qualitative or semiquantitative scoring assessments. The reliability of this analysis can be impaired by the subjectivity of these approaches, even when read by experienced pathologists. Furthermore, the laborious nature of manual image assessments often leads to the analysis being restricted to a relatively small number of images that may not accurately represent the whole sample. Thus, there is a clear need for automated image analysis tools that can provide robust and rapid quantification of histologic samples from paraffin-embedded or cryopreserved tissues. To address this need, we have developed a color image analysis algorithm (DigiPath) to quantify distinct color features in histologic sections. We demonstrate the utility of this tool across multiple types of tissue samples and pathologic features, and compare results from our program to other quantitative approaches such as color thresholding and hand tracing. We believe this tool will enable more thorough and reliable characterization of histological samples to facilitate better rigor and reproducibility in tissue-based analyses.

Inflammatory and fibrotic mechanisms in NAFLD-Implications for new treatment strategies

Non-alcoholic fatty liver disease is comprised of either simple steatosis (non-alcoholic fatty liver) or a more advanced inflammatory and fibrogenic stage (non-alcoholic steatohepatitis [NASH]). NASH affects a growing proportion of the global adult and pediatric population, leading to rising rates of liver fibrosis and hepatocellular carcinoma. NASH is a multifactorial disease that is part of a systemic metabolic disorder. Here, we provide an overview of the metabolic underpinnings of NASH pathogenesis and established drivers of inflammation and fibrosis. Clarification of underlying fibrogenic and inflammatory mechanisms will advance the development of novel treatment strategies as there are no approved therapies at present. We discuss emerging experimental approaches and potential novel investigational strategies derived from animal models including the inflammasome, epigenetic reprogramming, Hippo signaling, Notch signaling, engineered T cells to remove fibrogenic HSCs, and HSC-specific targeting therapies. Recently completed and ongoing clinical trials and antifibrotics are discussed, illuminating the growing expectation that one or more therapies will yield clinical benefit in NASH in the coming years.

m6A mRNA methylation-directed myeloid cell activation controls progression of NAFLD and obesity

N⁶-methyladenosine (m⁶A) RNA modification is a fundamental determinant of mRNA metabolism, but its role in innate immunity-driven non-alcoholic fatty liver disease (NAFLD) and obesity is not known. Here, we show that myeloid lineage-restricted deletion of the m⁶A “writer” protein Methyltransferase Like 3 (METTL3) prevents age-related and diet-induced development of NAFLD and obesity in mice with improved inflammatory and metabolic phenotypes. Mechanistically, loss of METTL3 results in the differential expression of multiple mRNA transcripts marked with m⁶A, with a notable increase of DNA Damage Inducible Transcript 4 (DDIT4) mRNA level. In METTL3-deficient macrophages, there is a significant downregulation of mammalian target of rapamycin (mTOR) and nuclear factor κB (NF-κB) pathway activity in response to cellular stress and cytokine stimulation, which can be restored by knockdown of DDIT4. Taken together, our findings identify the contribution of METTL3-mediated m⁶A modification of Ddit4 mRNA to macrophage metabolic reprogramming in NAFLD and obesity.

Myeloid deletion of METTL3 prevents age-related and diet-induced obesity and NAFLD in mice. Qin et al. reveal the contribution of METTL3 to maintaining macrophage homeostasis during NAFLD progression. METTL3 modulates metabolic adaptation of macrophage function in obesity and NAFLD via m⁶A-decorated DDIT4 mRNA degradation.

PKM2-dependent metabolic skewing of hepatic Th17 cells regulates pathogenesis of non-alcoholic fatty liver disease

Emerging evidence suggests a key contribution to non-alcoholic fatty liver disease (NAFLD) pathogenesis by Th17 cells. The pathogenic characteristics and mechanisms of hepatic Th17 cells, however, remain unknown. Here, we uncover and characterize a distinct population of inflammatory hepatic CXCR3+Th17 (ihTh17) cells sufficient to exacerbate NAFLD pathogenesis. Hepatic ihTh17 cell accrual was dependent on the liver microenvironment and CXCR3 axis activation. Mechanistically, the pathogenic potential of ihTh17 cells correlated with increased chromatin accessibility, glycolytic output, and concomitant production of IL-17A, IFNγ, and TNFα. Modulation of glycolysis using 2-DG or cell-specific PKM2 deletion was sufficient to reverse ihTh17-centric inflammatory vigor and NAFLD severity. Importantly, ihTh17 cell characteristics, CXCR3 axis activation, and hepatic expression of glycolytic genes were conserved in human NAFLD. Together, our data show that the steatotic liver microenvironment regulates Th17 cell accrual, metabolism, and competence toward an ihTh17 fate. Modulation of these pathways holds potential for development of novel therapeutic strategies for NAFLD.

The Role of PKM2 in Metabolic Reprogramming: Insights into the Regulatory Roles of Non-Coding RNAs

Pyruvate kinase is a key regulator in glycolysis through the conversion of phosphoenolpyruvate (PEP) into pyruvate. Pyruvate kinase exists in various isoforms that can exhibit diverse biological functions and outcomes. The pyruvate kinase isoenzyme type M2 (PKM2) controls cell progression and survival through the regulation of key signaling pathways. In cancer cells, the dimer form of PKM2 predominates and plays an integral role in cancer metabolism. This predominance of the inactive dimeric form promotes the accumulation of phosphometabolites, allowing cancer cells to engage in high levels of synthetic processing to enhance their proliferative capacity. PKM2 has been recognized for its role in regulating gene expression and transcription factors critical for health and disease. This role enables PKM2 to exert profound regulatory effects that promote cancer cell metabolism, proliferation, and migration. In addition to its role in cancer, PKM2 regulates aspects essential to cellular homeostasis in non-cancer tissues and, in some cases, promotes tissue-specific pathways in health and diseases. In pursuit of understanding the diverse tissue-specific roles of PKM2, investigations targeting tissues such as the kidney, liver, adipose, and pancreas have been conducted. Findings from these studies enhance our understanding of PKM2 functions in various diseases beyond cancer. Therefore, there is substantial interest in PKM2 modulation as a potential therapeutic target for the treatment of multiple conditions. Indeed, a vast plethora of research has focused on identifying therapeutic strategies for targeting PKM2. Recently, targeting PKM2 through its regulatory microRNAs, long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) has gathered increasing interest. Thus, the goal of this review is to highlight recent advancements in PKM2 research, with a focus on PKM2 regulatory microRNAs and lncRNAs and their subsequent physiological significance.

Pathogenesis of NASH and Promising Natural Products

Nonalcoholic steatohepatitis (NASH) is a common clinical condition that can lead to advanced liver diseases. The mechanism of the diaease progression, which is lacking effective therapy, remains obsure. Therefore, there is a need to understand the pathogenic mechanisms responsible for disease development and progression in order to develop innovative therapies. To accomplish this goal, experimental animal models that recapitulate the human disease are necessary. Currently, an increasing number of studies have focused on natural constituents from medicinal plants which have been emerged as a new hope for NASH. This review summarized the pathogenesis of NASH, animal models commonly used, and the promising targets for therapeutics. We also reviewed the natural constituents as potential NASH therapeutic agents.

HIF-1α is a Potential Molecular Target for Herbal Medicine to Treat Diseases

HIF-1α is an important factor regulating oxygen balance in mammals, and its expression is closely related to various physiological and pathological conditions of the body. Because HIF-1α plays an important role in the occurrence and development of cancer and other diseases, it has become an enduring research hotspot. At the same time, natural medicines and traditional Chinese medicine compounds have amazing curative effects in various diseases related to HIF-1 subtype due to their unique pharmacological effects and more effective ingredients. Therefore, in this article, we first outline the structure of HIF-1α and the regulation related to its expression, then introduce various diseases closely related to HIF-1α, and finally focus on the regulation of natural medicines and compound Chinese medicines through various pathways. This will help us understand HIF-1α systematically, and use HIF-1α as a target to discover more natural medicines and traditional Chinese medicines that can treat related diseases.

The NLRP3 Inflammasome: Metabolic Regulation and Contribution to Inflammaging

In response to inflammatory stimuli, immune cells reconfigure their metabolism and bioenergetics to generate energy and substrates for cell survival and to launch immune effector functions. As a critical component of the innate immune system, the nucleotide-binding and oligomerization domain, leucine-rich repeat, and pyrin domain-containing 3 (NLRP3) inflammasome can be activated by various endogenous and exogenous danger signals. Activation of this cytosolic multiprotein complex triggers the release of the pro-inflammatory cytokines interleukin (IL)-1β and IL-18 and initiates pyroptosis, an inflammatory form of programmed cell death. The NLRP3 inflammasome fuels both chronic and acute inflammatory conditions and is critical in the emergence of inflammaging. Recent advances have highlighted that various metabolic pathways converge as potent regulators of the NLRP3 inflammasome. This review focuses on our current understanding of the metabolic regulation of the NLRP3 inflammasome activation, and the contribution of the NLRP3 inflammasome to inflammaging.

Macrophages in metabolic associated fatty liver disease

Metabolic associated fatty liver disease (MAFLD), formerly named non-alcoholic fatty liver disease is the most common liver disorder in many countries. The inflammatory subtype termed steatohepatitis is a driver of disease progression to cirrhosis, hepatocellular carcinoma, liver transplantation, and death, but also to extrahepatic complications including cardiovascular disease, diabetes and chronic kidney disease. The plasticity of macrophages in response to various environmental cues and the fact that they can orchestrate cross talk between different cellular players during disease development and progression render them an ideal target for drug development. This report reviews recent advances in our understanding of macrophage biology during the entire spectrum of MAFLD including steatosis, inflammation, fibrosis, and hepatocellular carcinoma, as well as for the extra-hepatic manifestations of MAFLD. We discuss the underlying molecular mechanisms of macrophage activation and polarization as well as cross talk with other cell types such as hepatocytes, hepatic stellate cells, and adipose tissue. We conclude with a discussion on the potential translational implications and challenges for macrophage based therapeutics for MAFLD.