Interleukin-22 drives a metabolic adaptive reprogramming to maintain mitochondrial fitness and treat liver injury

Review of the potential value of serum interleukin levels as prognostic biomarkers of liver failure

Liver failure (LF) is prevalent in China and is characterized by complex pathogenesis, challenging clinical management, poor prognosis, and rising incidence and mortality rates. The immune status is an important factor affecting LF prognosis. Interleukins (Ils) are a type of cytokine that act and interact with multiple cells, including immune cells. These signaling molecules play important roles in intercellular information transmission, including the regulation of immune cells; mediation of the activation, proliferation, and differentiation of T and B cells; and orchestration of the inflammatory response. To date, many studies have explored the correlation between IL expression and liver disease prognosis, but few studies have evaluated Ils as the prognostic biomarkers of LF. This article reviews the potential use of Ils as the prognostic biomarkers of LF. Particularly, it evaluates the predictive values of IL-21, IL-22, and IL-31, the three often overlooked yet promising prognostic biomarkers, in predicting susceptibility to LF. Harnessing biomarkers for early prognostic insights can facilitate tailored treatment strategies and enhance patient survival. Thus, this article focuses on the identification of IL-21, IL-22, and IL-33 as biomarkers in preclinical and clinical studies on LF and reviews their role as biomarkers in the pathogenesis and diagnosis of LF.

Interleukin-22 inhibits cardiac fibrosis by regulating fibroblast metabolic reprogramming in myocardial infarction

Cardiac fibrosis, a significant characteristic of cardiovascular diseases, leads to ventricular remodeling and impaired cardiac function. In this study, we aimed to investigate the role of Interleukin-22 (IL-22) in myocardial fibrosis following myocardial infarction (MI) and to explore the underlying metabolic mechanisms. Here we analyzed the single-cell sequencing data and found that the level of aerobic glycolysis was significantly higher in cardiac fibrosis in MI patient, which we validated through in vivo experiments. Utilizing MI mouse model, these experiments revealed decreased serum IL-22 levels and increased levels of AngII and TGF-β1. However, treatment with exogenous IL-22 reversed these changes, reduced infarct size, and fibrosis. In vitro experiments demonstrated that IL-22 inhibited AngII-induced fibroblast-to-myofibroblast transition (FMT) by suppressing the expression of α-SMA, Cola1, and Cola3. Metabolic analysis indicated that IL-22 decreased the expression of glycolytic enzymes and reduced lactate production in cardiac fibroblasts. Further in vivo experiments confirmed the inhibitory effect of IL-22 on Pyruvate kinase isoform M2 (PKM2) levels in heart tissue. Additionally, IL-22 activated the c-Jun N-terminal kinase (JNK) pathway, while inhibition of JNK partially reversed IL-22's effect on PKM2 activity. These findings suggest that IL-22 mitigates cardiac fibrosis and FMT by inhibiting aerobic glycolysis by activating the JNK/PKM2 pathway. Our study highlights IL-22 as a potential therapeutic target for myocardial fibrosis and cardiovascular diseases, providing insights into its role in regulating fibrosis and glycolysis. These findings pave the way for developing targeted therapies and investigating additional metabolic pathways for improved treatment outcomes in the field of cardiovascular diseases.

B. longum CKD1 enhances the efficacy of anti-diabetic medicines through upregulation of IL- 22 response in type 2 diabetic mice

The gut microbiota plays a pivotal role in metabolic disorders, notably type 2 diabetes mellitus (T2DM). In this study, we investigated the synergistic potential of combining the effects of Bifidobacterium longum NBM7-1 (CKD1) with anti-diabetic medicines, LobeglitazoneⓇ (LO), SitagliptinⓇ (SI), and MetforminⓇ (Met), to alleviate hyperglycemia in a diabetic mouse model. CKD1 effectively mitigated insulin resistance, hepatic steatosis, and enhanced pancreatic β-cell function, as well as fortifying gut-tight junction integrity. In the same way, SI-CKD1 and Met- CKD1 synergistically improved insulin sensitivity and prevented hepatic steatosis, as evidenced by the modulation of key genes associated with insulin signaling, β-oxidation, gluconeogenesis, adipogenesis, and inflammation by qRT-PCR. The comprehensive impact on modulating gut microbiota composition was observed, particularly when combined with MetforminⓇ. This combination induced an increase in the abundance of Rikenellaceae and Alistipes related negatively to the T2DM incidence while reducing the causative species of Cryptosporangium, Staphylococcaceae, and Muribaculaceae. These alterations intervene in gut microbiota metabolites to modulate the level of butyrate, indole-3-acetic acid, propionate, and inflammatory cytokines and to activate the IL-22 pathway. However, it is meaningful that the combination of B. longum NBM7-1(CKD1) reduced the medicines' dose to the level of the maximal inhibitory concentrations (IC50). This study advances our understanding of the intricate relationship between gut microbiota and metabolic disorders. We expect this study to contribute to developing a prospective therapeutic strategy modulating the gut microbiota.

LncRNA H19: a novel player in the regulation of diabetic kidney disease

Diabetic kidney disease (DKD), one of the most severe complications of diabetes mellitus (DM), has received considerable attention owing to its increasing prevalence and contribution to chronic kidney disease (CKD) and end-stage kidney disease (ESRD). However, the use of drugs targeting DKD remains limited. Recent data suggest that long non-coding RNAs (lncRNAs) play a vital role in the development of DKD. The lncRNA H19 is the first imprinted gene, which is expressed in the embryo and down-regulated at birth, and its role in tumors has long been a subject of controversy, however, in recent years, it has received increasing attention in kidney disease. The LncRNA H19 is engaged in the pathological progression of DKD, including glomerulosclerosis and tubulointerstitial fibrosis via the induction of inflammatory responses, apoptosis, ferroptosis, pyroptosis, autophagy, and oxidative damage. In this review, we highlight the most recent research on the molecular mechanism and regulatory forms of lncRNA H19 in DKD, including epigenetic, post-transcriptional, and post-translational regulation, providing a new predictive marker and therapeutic target for the management of DKD.

Interleukin-22 Inhibits Apoptosis of Gingival Epithelial Cells Through TGF-β Signaling Pathway During Periodontitis

Periodontitis is a chronic inflammatory disease characterized by the destruction of tooth-supporting tissues. The gingival epithelium is the first barrier of periodontal tissue against oral pathogens and harmful substances. The structure and function of epithelial lining are essential for maintaining the integrity of the epithelial barrier. Abnormal apoptosis can lead to the decrease of functional keratinocytes and break homeostasis in gingival epithelium. Interleukin-22 is a cytokine that plays an important role in epithelial homeostasis in intestinal epithelium, inducing proliferation and inhibiting apoptosis, but its role in gingival epithelium is poorly understood. In this study, we investigated the effect of interleukin-22 on apoptosis of gingival epithelial cells during periodontitis. Interleukin-22 topical injection and Il22 gene knockout were performed in experimental periodontitis mice. Human gingival epithelial cells were co-cultured with Porphyromonas gingivalis with interleukin-22 treatment. We found that interleukin-22 inhibited apoptosis of gingival epithelial cells during periodontitis in vivo and in vitro, decreasing Bax expression and increasing Bcl-xL expression. As for the underlying mechanisms, we found that interleukin-22 reduced the expression of TGF-β receptor type II and inhibited the phosphorylation of Smad2 in gingival epithelial cells during periodontitis. Blockage of TGF-β receptors attenuated apoptosis induced by Porphyromonas gingivalis and increased Bcl-xL expression stimulated by interleukin-22. These results confirmed the inhibitory effect of interleukin-22 on apoptosis of gingival epithelial cells and revealed the involvement of TGF-β signaling pathway in gingival epithelial cell apoptosis during periodontitis.

Novel treatment of acute and acute-on-chronic liver failure: Interleukin-22

Acute liver failure (ALF) is a life-threatening medical condition, characterized by rapidly progressive hepatic dysfunction, coagulopathy and hepatic encephalopathy in patients without chronic liver disease, while acute-on-chronic liver failure (ACLF) occurs in patients with existing chronic liver disease. ALF and ACLF are often associated with multiple organ failure and a high short-term mortality. In this review, we briefly discuss the causes and pathogenesis of ALF and ACLF, the current options available for the treatment of both deadly maladies and interleukin-22 (IL-22), a novel promising drug that may have great therapeutic potential for ALF and ACLF treatment. IL-22 is a cytokine produced by immune cells but mainly targets epithelial cells including hepatocytes. IL-22 has been shown to protect against organ damage and reduce bacterial infection in many preclinical models and several clinical trials including alcohol-associated hepatitis. The potential application of IL-22 for the treatment of ALF and ACLF is also elaborated.

Triptolide Shows High Sensitivity and Low Toxicity Against Acute Myeloid Leukemia Cell Lines Through Inhibiting WSTF-RNAPII Complex

Triptolide exhibits superior and broad-spectrum antitumor activity. However, the narrow safety window caused by the toxicity of triptolide limits its clinical applications. Although several characterized targets for triptolide are reported, the association between triptolide and its targets in cancer therapy is not fully understood. Here, we show that acute myeloid leukemia (AML) cell lines are sensitive to triptolide by constructing an in vitro cell and in vivo xenograft models. Meanwhile, the triptolide-induced hepatotoxicity increases with increasing dosages within the xenograft models. Additionally, the expression levels of WSTF-RPB1 are strongly associated with the sensitivity to triptolide in hematological cancer cells and can be downregulated in a dose and time-dependent manner. Finally, we show that optimizing dosing regimens can achieve the same pharmaceutical effect and reduce toxicity. In summary, this study aims to search for triptolide-sensitive cell lines as well as the underlying molecular mechanisms in order to broaden the safety window of triptolide; thus, increasing its clinical utility.

Atractylenolide I Ameliorates Acetaminophen-Induced Acute Liver Injury via the TLR4/MAPKs/NF-κB Signaling Pathways

Background: Acetaminophen (APAP) overdose results in the production of reactive oxygen species (ROS), induces hepatocyte necrosis, and leads to acute liver failure. Atractylenolide I (AO-I), a phytochemical found in Atractylodes macrocephala Koidz, is known to exhibit antioxidant activity. However, its clinical benefits against drug-induced liver injury remain largely unclear.

Purpose: This study aimed at evaluating the protective effects of AO-I against APAP-induced acute liver injury.

Methods: C57BL/6 mice were administered 500 mg/kg APAP to induce hepatotoxicity. AO-Ⅰ (60 and 120 mg/kg) was intragastrically administered 2 h before APAP dosing. Liver histopathological changes, oxidative stress and hepatic inflammation markers from each group were observed.

Results: We observed that AO-I treatment significantly reversed APAP-induced liver injury, as evidenced by improved plasma alanine transaminase (ALT) level, aspartate aminotransferase (AST) and liver H&E stain. APAP treatment increased liver malondialdehyde (MDA) content and reduced catalase (CAT) and glutathione (GSH) level; however, these effects were alleviated by AO-I intervention. Moreover, AO-I treatment significantly inhibited APAP-induced activation of pro-inflammatory factors, such as IL-1β, IL-6, and TNF-α, at both the mRNA and protein levels. Mechanistic studies revealed that AO-I attenuated APAP-induced activation of TLR4, NF-κB and MAPKs (including JNK and p38).

Conclusion: AO-I mediates protective effects against APAP-induced hepatotoxicity via the TLR4/MAPKs/NF-κB pathways. Thus, AO-I is a candidate therapeutic compound for APAP-induced hepatotoxicity.

Autophagy Induced by Micheliolide Alleviates Acute Irradiation-Induced Intestinal Injury via Inhibition of the NLRP3 Inflammasome

Radiation-induced enteropathy (RIE) is one of the most common and fatal complications of abdominal radiotherapy, with no effective interventions available. Pyroptosis, a form of proinflammatory regulated cell death, was recently found to play a vital role in radiation-induced inflammation and may represent a novel therapeutic target for RIE. To investigate this, we found that micheliolide (MCL) exerted anti-radiation effects in vitro. Therefore, we investigated both the therapeutic effects of MCL in RIE and the possible mechanisms by which it may be therapeutic. We developed a mouse model of RIE by exposing C57BL/6J mice to abdominal irradiation. MCL treatment significantly ameliorated radiation-induced intestinal tissue damage, inflammatory cell infiltration, and proinflammatory cytokine release. In agreement with these observations, the beneficial effects of MCL treatment in RIE were abolished in Becn1^+/− mice. Furthermore, super-resolution microscopy revealed a close association between NLR pyrin domain three and lysosome-associated membrane protein/light chain 3-positive vesicles following MCL treatment, suggesting that MCL facilitates phagocytosis of the NLR pyrin domain three inflammasome. In summary, MCL-mediated induction of autophagy can ameliorate RIE by NLR pyrin domain three inflammasome degradation and identify MCL as a novel therapy for RIE.

Fast DNA Vaccination Strategy Elicits a Stronger Immune Response Dependent on CD8+CD11c+ Cell Accumulation

Conventional DNA vaccine strategies usually employ a regimen of immunizations at 2-week or longer intervals to induce effective memory cell-dependent immune responses. Clinical cancer treatment requires a faster immunization strategy to contend with tumor progression. In this study, a novel fast immunization strategy was established, wherein a DNA vaccine was intramuscularly administered on days 0, 2, and 5 in a murine lung cancer model. Effector cells peaked 7 to 10 days after the last vaccination. Compared with traditional 2-week-interval immunization strategies, antigen-specific cytolysis and INF-γ secretion were significantly enhanced under the fast vaccination approach. As a result, the rapidly administered DNA vaccine elicited stronger and more prompt antitumor effects. The probable underlying mechanism of fast immunization was the accumulation of CD8⁺CD11c⁺ antigen-presenting cells at the injection site, which enhanced subsequent antigen presentation. In conclusion, the fast DNA vaccination strategy shortened vaccination time to 5 days and elicited a stronger antitumor immune response.

Therapeutic Opportunities of IL-22 in Non-Alcoholic Fatty Liver Disease: From Molecular Mechanisms to Clinical Applications

Nonalcoholic fatty liver disease (NAFLD) represents one of the most common liver disorders and can progress into a series of liver diseases, including nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and even liver cancer. Interleukin-22 (IL-22), a member of the IL-10 family of cytokines, is predominantly produced by lymphocytes but acts exclusively on epithelial cells. IL-22 was proven to favor tissue protection and regeneration in multiple diseases. Emerging evidence suggests that IL-22 plays important protective functions against NAFLD by improving insulin sensitivity, modulating lipid metabolism, relieving oxidative and endoplasmic reticulum (ER) stress, and inhibiting apoptosis. By directly interacting with the heterodimeric IL-10R2 and IL-22R1 receptor complex on hepatocytes, IL-22 activates the Janus kinase 1 (JAK1)/ signal transducer and activator of transcription 3 (STAT3), c-Jun N-terminal kinase (JNK) and extracellular-signal regulated kinase (ERK) pathways to regulate the subsequent expression of genes involved in inflammation, metabolism, tissue repair, and regeneration, thus alleviating hepatitis and steatosis. However, due to the wide biodistribution of the IL-22 receptor and its proinflammatory effects, modifications such as targeted delivery of IL-22 expression and recombinant IL-22 fusion proteins to improve its efficacy while reducing systemic side effects should be taken for further clinical application. In this review, we summarized recent progress in understanding the physiological and pathological importance of the IL-22-IL-22R axis in NAFLD and the mechanisms of IL-22 in the protection of NAFLD and discussed the potential strategies to maneuver this specific cytokine for therapeutic applications for NAFLD.

Identification of Immune-Related LncRNA Pairs for Predicting Prognosis and Immunotherapeutic Response in Head and Neck Squamous Cell Carcinoma

Long noncoding RNAs (lncRNAs) have multiple functions with regard to the cancer immunity response and the tumor microenvironment. The prognosis of head and neck squamous cell carcinoma (HNSCC) is still poor currently, and it may be effective to predict the clinical outcome and immunotherapeutic response of HNSCC by immunogenic analysis. Therefore, by using univariate COX analysis and Lasso Cox regression, we identified a signature consisting of 21 immune-related lncRNA pairs (IRLPs) that predicted clinical outcome and Immunotherapeutic response in HNSCC. Specifically, it was associated with immune cell infiltration (i.e., T cells CD4 memory resting, CD8 T cells, macrophages M0, M2, and NK cells), and more importantly this signature was strongly related with immune checkpoint inhibitors (ICIs) [such as PDCD1 (r = -0.35, P < 0.001), CTLA4 (r = -0.26, P < 0.001), LAG3 (r = -0.22, P < 0.001) and HAVCR2 (r = -0.2, P < 0.001)] and immunotherapy-related biomarkers (MMR and HLA). The present study highlighted the value of the 21 IRLPs signature as a predictor of prognosis and immunotherapeutic response in HNSCC.

Targeting Certain Interleukins as Novel Treatment Options for Liver Fibrosis

The liver is a major metabolic organ and an immunologically complex organ. It produces and uses many substances such as acute phase proteins, cytokines, chemokines, and complementary components to maintain the balance between immunity and tolerance. Interleukins are important immune control cytokines, that are produced by many body cells. In liver injury, interleukins are produced in large amount by various cell types, and act as pro-inflammatory (e.g. interleukin (IL)-6, IL-13, IL-17, and IL-33) as well as anti-inflammatory (e.g. IL-10) functions in hepatic cells. Recently, interleukins are regarded as interesting therapeutic targets for the treatment of liver fibrosis patients. Hepatic cells such as hepatocytes, hepatic stellate cells, and hepatic macrophages are involved to the initiation, perpetuation, and resolution of fibrosis. The understanding of the role of interleukins in such cells provides opportunity for the development of therapeutic target drugs. This paper aims to understand the functional roles of interleukins in hepatic and immune cells when the liver is damaged, and suggests the possibility of interleukins as a new treatment target in liver fibrosis.

IL-22-mediated renal metabolic reprogramming via PFKFB3 to treat kidney injury

Kidney damage initiates the deteriorating metabolic states in tubule cells that lead to the development of end-stage renal disease (ESTD). Interleukin-22 (IL-22) is an effective therapeutic antidote for kidney injury via promoting kidney recovery, but little is known about the underlying molecular mechanisms. Here, we first provide evidence that IL-22 attenuates kidney injury via metabolic reprogramming of renal tubular epithelial cells (TECs). Specifically, our data suggest that IL-22 regulates mitochondrial function and glycolysis in damaged TECs. Further observations indicate that IL-22 alleviates the accumulation of mitochondrial reactive oxygen species (ROS) and dysfunctional mitochondria via the induction of AMPK/AKT signaling and PFBFK3 activities. In mice, amelioration of kidney injury and necrosis and improvement of kidney functions via regulation of these metabolism relevant signaling and mitochondrial fitness of recombinant IL-22 are certificated in cisplatin-induced kidney damage and diabetic nephropathy (DN) animal models. Taken together, our findings unravel new mechanistic insights into protective effects of IL-22 on kidneys and highlight the therapeutic opportunities of IL-22 and the involved metabolic regulators in various kidney diseases.

PKM2 Drives Hepatocellular Carcinoma Progression by Inducing Immunosuppressive Microenvironment

Background and Aims

Pyruvate kinase M2 (PKM2) is an essential regulator of the Warburg effect, but its biological function promoting immune escape of hepatocellular carcinoma (HCC) is unclear.

Methods

GEPIA web tool and immunohistochemistry (IHC) analysis were employed to evaluate the clinical relevance of PKM2 in HCC patients. Both in vitro CCK-8, colony formation, and transwell assays, and in vivo xenografts were performed to evaluate the malignancy of HCC cells. PKM2 and PD-L1 levels were examined by Western blot, qRT-PCR, and IHC. The role of PKM2 on in vivo immune response was also investigated.

Results

PKM2 was significantly upregulated in HCC and associated with a poor prognosis of HCC patients. Knockdown of PKM2 inhibited in vitro proliferation, migration, and invasion of HCC cells, as well as in vivo tumor growth. Strikingly, PKM2 showed a strong correlation with the expression of immune inhibitory cytokines and lymphocyte infiltration in HCC. The overexpression of PKM2 sensitized HCC to immune checkpoint blockade, which enhanced IFN-γ positive CD8 T cells in HCC mice models.

Conclusion

PKM2 might be a predictor and a potential therapeutic target for immune checkpoint inhibitors in HCC.

Interleukin-22 in alcoholic hepatitis and beyond

Alcoholic hepatitis (AH) is a clinical syndrome characterized by jaundice and progressive inflammatory liver injury in patients with a history of prolonged periods of excess alcohol consumption and recent heavy alcohol abuse. Severe AH is a life-threatening form of alcohol-associated liver disease with a high short-term mortality rate around 30-50% at one month from the initial presentation. A large number of pro-inflammatory mediators, metabolic pathways, transcriptional factors and epigenetic factors have been suggested to be associated with the development and progression of AH. Several factors may contribute to liver failure and mortality in patients with severe AH including hepatocyte death, inflammation, and impaired liver regeneration. Although the pathogeneses of AH have been extensively investigated and many therapeutic targets have been identified over the last five decades, no new drugs for AH have been successfully developed. In this review, we discuss interleukin-22 (IL-22) biology and its roles of anti-apoptosis, anti-fibrosis, anti-oxidation, anti-bacterial infection and regenerative stimulation in protecting against liver injury in many preclinical models including several recently developed models such as chronic-plus-binge ethanol feeding, acute-on-chronic liver failure, C-X-C motif chemokine ligand 1 plus high-fat diet-induced nonalcoholic steatohepatitis. Finally, clinical trials of IL-22 for the treatment of AH are also discussed, which showed some promising benefits for AH patients.

Interleukin-22 acts as a mitochondrial protector

Interleukin (IL)-22 has been increasingly recognized as a promising therapeutic option for various types of diseases. This commentary summarizes the novel mechanistic aspects of IL-22 for the treatment of liver diseases including the study by Chen et al. published in the recent issue of the Theranostics that elucidated the novel function of IL-22 as a mitochondrial protector for the adaptive defense against liver injury.