alpha-Tocopherol supplementation reduces inflammation and apoptosis in high cholesterol mediated nonalcoholic steatohepatitis

A Comprehensive Insight into Apoptosis: Molecular Mechanisms, Signaling Pathways, and Modulating Therapeutics

Apoptosis, or programmed cell death, is a fundamental biological process essential for maintaining tissue homeostasis. Dysregulation of apoptosis is implicated in a variety of diseases, including cancer, neurodegenerative disorders, and autoimmune conditions. This review provides an in-depth insight into the molecular mechanisms and signaling pathways that regulate apoptosis, highlighting both intrinsic and extrinsic pathways. Additionally, the review explains the tumor microenvironment's influence on apoptosis and its implications for cancer therapy resistance. Understanding the complex interplay between apoptotic signaling and cellular responses is crucial for developing targeted therapies that can effectively manage diseases associated with apoptosis dysregulation. The effects of conventional therapeutics and alternative substances with natural sources such as herbal compounds, alongside vitamins, minerals, and trace elements on cellular homeostasis and disease pathogenesis have been thoroughly investigated. Moreover, recent advances in therapeutic strategies aimed at modulating apoptosis are discussed, with a focus on novel interventions such as nutrition bio shield dietary supplement. These emerging approaches offer potential benefits beyond conventional treatments by selectively targeting apoptotic pathways to inhibit cancer progression and metastasis. By integrating insights from recent studies, this review aims to enhance our understanding of apoptosis and guide future research in developing innovative therapeutic approaches.

The use of vitamin E in ocular health: Bridging omics approaches with Tocopherol and Tocotrienol in the management of glaucoma

Vitamin E, encompassing tocopherols and tocotrienols is celebrated for its powerful antioxidant properties, which help neutralize free radicals and protect cells from oxidative damage. Over the years, research has shown that both tocopherols and tocotrienols offer significant benefits, including protection against radiation damage, cholesterol regulation, cardiovascular health, and neurological disorders. This wide range of benefits highlights the need for further exploration of vitamin E's role in managing various diseases. One particularly promising area is its potential application in treating ocular diseases like glaucoma. Despite advances in treatment, current options have limitations, making the investigation of alternative approaches crucial. Omics technologies, which allow for a detailed examination of biological systems, could provide valuable insights into how tocopherols and tocotrienols work at a molecular level. Their neuroprotective and antioxidative properties make them promising candidates for glaucoma management. Additionally, the sustainability of vitamin E is noteworthy, as by-products from its production can be repurposed into valuable resources for nutraceuticals and pharmaceuticals. As research continues, integrating omics technologies with the study of vitamin E derivatives could unveil new therapeutic possibilities, further enhancing our understanding of its diverse health benefits and its potential role in preventing and managing diseases.

Associations of dietary sources of antioxidant intake and NAFLD: NHANES 2017-2020 and Mendelian randomization

Purpose

To determine the association between dietary antioxidant sources and non-alcoholic fatty liver disease (NAFLD).

Methods

In this observational study, we utilized NHANES 2017-2020 data to identify the factors associated with NAFLD in dietary antioxidant sources via weighted multivariate logistic regression models. Then, Mendelian randomization (MR) was applied to investigate the effect of dietary antioxidant sources on NAFLD at the genetic level.

Results

Of the six dietary sources of antioxidants, only vitamin E (Vit E) was significantly associated with NAFLD (OR = 0.98; 95% CI: 0.97-0.99; p = 0.001). Upon adjusting for all covariates, it was determined that the highest quartile of dietary Vit E intake was associated with a decreased NAFLD occurrence compared with the lowest quartile of dietary Vit E intake (p < 0.001). The results of IVW-MR analysis revealed an association between Vit E and NAFLD (OR = 0.028; p = 0.039).

Conclusion

Our research indicates a negative and linear relationship between daily vitamin E intake and NAFLD.

Protective effect of alpha-tocopherol on lipogenesis and oxysterol production in hypercholesterolemia-induced nonalcoholic steatohepatitis

Despite limited number of studies, oxysterols are known to contribute to the progression of nonalcoholic steatohepatitis (NASH) by affecting lipid/cholesterol metabolism and elevating proinflammatory and profibrotic processes. Accordingly, we used a high cholesterol-mediated in vivo NASH model and aimed to determine alterations in fatty acid content and oxysterol levels together with their effects on cholesterol/lipid metabolism during the progression of the disease. We further investigated the beneficial role of α-tocopherol. To this end, in our hypercholesterolemic rabbit model, we determined fatty acid profile by GC-MS while 25-, 27-, 4β-, 7α, and 24(S)-Hydroxycholesterol levels by means of LC-MS/MS. Additionally, lipid (SREBP-1c, PPARα, PPARγ) and cholesterol metabolism-related proteins (LXRα, SREBP2 and ABCA1) were determined by immunoblotting. In conclusion, the present findings provide a complete analysis of the hepatic alterations in lipid and oxysterol profiles mediated by a high-cholesterol diet. In addition, this study explains the protective effect of α-tocopherol on lipogenesis and oxysterol production in hypercholesterolemia-induced NASH. We believe that present study will guide to novel theories in the progression and therapeutic targeting of fatty liver diseases.

Targeting cell death in NAFLD: mechanisms and targeted therapies

Nonalcoholic fatty liver disease (NAFLD) is a group of chronic liver disease which ranges from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH) and is characterized by lipid accumulation, inflammation activation, fibrosis, and cell death. To date, a number of preclinical studies or clinical trials associated with therapies targeting fatty acid metabolism, inflammatory factors and liver fibrosis are performed to develop effective drugs for NAFLD/NASH. However, few therapies are cell death signaling-targeted even though the various cell death modes are present throughout the progression of NAFLD/NASH. Here we summarize the four types of cell death including apoptosis, necroptosis, pyroptosis, and ferroptosis in the NAFLD and the underlying molecular mechanisms by which the pathogenic factors such as free fatty acid and LPS induce cell death in the pathogenesis of NAFLD. In addition, we also review the effects of cell death-targeted therapies on NAFLD. In summary, our review provides comprehensive insight into the roles of various cell death modes in the progression of NAFLD, which we hope will open new avenues for therapeutic intervention.

An herbal formulation "Shugan Xiaozhi decoction" ameliorates methionine/choline deficiency-induced nonalcoholic steatohepatitis through regulating inflammation and apoptosis-related pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Shugan Xiaozhi (SGXZ) decoction is a traditional Chinese medicine used for treating nonalcoholic steatohepatitis (NASH). It has been used clinically for over 20 years and proved to be effective; however, the molecular mechanism underlying the effects of SGXZ decoction remains unclear.

AIM OF THE STUDY

We analyzed the chemical components, core targets, and molecular mechanisms of SGXZ decoction to improve NASH through network pharmacology and in vivo experiments.

MATERIALS AND METHODS

The chemical components, core targets, and related signaling pathways of SGXZ decoction intervention in NASH were predicted using network pharmacology. Molecular docking was performed to verify chemical components and their core targets. The results were validated in the NASH model treated with SGXZ decoction. Mouse liver function was assessed by measuring ALT and AST levels. TC and TG levels were determined to evaluate lipid metabolism, and lipid deposition was assessed via oil red O staining. Mouse liver damage was determined via microscopy following hematoxylin and eosin staining. Liver fibrosis was assessed via Masson staining. Western blot (WB) and immunohistochemical (IHC) analyses were performed to detect inflammation and the expression of apoptosis-related proteins, including IL-1β, IL-6, IL-18, TNF-α, MCP1, p53, FAS, Caspase-8, Caspase-3, Caspase-9, Bax, Bid, Cytochrome c, Bcl-2, and Bcl-XL. In addition, WB and IHC were used to assess protein expression associated with the TLR4/MyD88/NF-κB pathway.

RESULTS

Quercetin, luteolin, kaempferol, naringenin, and nobiletin in SGXZ decoction were effective chemical components in improving NASH, and TNF-α, IL-6, and IL-1β were the major core targets. Molecular docking indicated that these chemical components and major core targets might interact. KEGG pathway analysis showed that the pathways affected by SGXZ decoction, primarily including apoptosis and TLR4/NF-κB signaling pathways, interfere with NASH. In vivo experiments indicated that SGXZ decoction considerably ameliorated liver damage, fibrosis, and lipid metabolism disorder in MCD-induced NASH mouse models. In addition, WB and IHC verified the underlying molecular mechanisms of SGXZ decoction as predicted via network pharmacology. SGXZ decoction inhibited the activation of apoptosis-related pathways in MCD-induced NASH mice. Moreover, SGXZ decoction suppressed the activation of TLR4/MyD88/NF-κB pathway in MCD-induced NASH mice.

CONCLUSION

SGXZ decoction can treat NASH through multiple targets and pathways. These findings provide new insights into the effective treatment of NASH using SGXZ decoction.

Macrophage metabolism impacts metabolic dysfunction-associated steatotic liver disease and its progression

Metabolic dysfunction-associated steatotic liver disease (MASLD), with a progressive form of metabolic dysfunction-associated steatohepatitis (MASH), is the leading chronic liver disease worldwide, which can progress to advanced liver disease and hepatocellular carcinoma. MASLD is tightly associated with metabolic disorders such as obesity, insulin resistance, and type 2 diabetes. Macrophages, as an innate immune component and a linker of adaptive immune response, play important roles in the pathogenesis and treatment of MASLD or MASH. Metabolic reprogramming can regulate macrophage activation and polarization to inhibit MASLD or MASH progression to advanced liver disease. Here, we summarize the underlying mechanisms of how different metabolites such as amino acids, glucose, and fatty acids can regulate macrophage function and phenotype, the factors that regulate macrophage metabolism, and potential treatment options to regulate macrophage function in MASLD or MASH, as well as other associated metabolic disorders.

Impact of Seipin in cholesterol mediated lipid droplet maturation; status of endoplasmic reticulum stress and lipophagy

The global prevalence of nonalcoholic fatty liver disease (NAFLD) defined by the increased number of lipid droplets (LDs) in hepatocytes, have risen continuously in parallel with the obesity. LDs and related proteins are known to affect cellular metabolism and signaling. Seipin, one of the most important LD-related proteins, plays a critical role in LD biogenesis. Although the role of adipose tissue-specific Seipin silencing is known, hepatocyte-specific silencing upon cholesterol-mediated lipid accumulation has not been investigated. In our study, we investigated the effect of Seipin on endoplasmic reticulum (ER) stress and lipophagy in cholesterol accumulated mouse hepatocyte cells. In this direction, cholesterol accumulation was induced by cholesterol-containing liposome, while Seipin mRNA and protein levels were reduced by siRNA. Our findings show that cholesterol containing liposome administration in hepatocytes increases both Seipin protein and number of large LDs. However Seipin silencing reduced the increase of cholesterol mediated large LDs and Glucose-regulated protein 78 (GRP78) mRNA. Additionally, lysosome-LD colocalization increased only in cells treated with cholesterol containing liposome, while the siRNA against Seipin did not lead any significant difference. According to our findings, we hypothesize that Seipin silencing in hepatocytes reduced cholesterol mediated LD maturation as well as GRP78 levels, but not lipophagy.

The advancements in targets for ferroptosis in liver diseases

Ferroptosis is a type of regulated cell death caused by iron overload and lipid peroxidation, and its core is an imbalance of redox reactions. Recent studies showed that ferroptosis played a dual role in liver diseases, that was, as a therapeutic target and a pathogenic factor. Therefore, herein, we summarized the role of ferroptosis in liver diseases, reviewed the part of available targets, such as drugs, small molecules, and nanomaterials, that acted on ferroptosis in liver diseases, and discussed the current challenges and prospects.

Dietary Administration of Black Raspberries and Arsenic Exposure: Changes in the Gut Microbiota and Its Functional Metabolites

Mounting evidence has linked berries to a variety of health benefits. We previously reported that administration of a diet rich in black raspberries (BRBs) impacted arsenic (As) biotransformation and reduced As-induced oxidative stress. To further characterize the role of the gut microbiota in BRB-mediated As toxicity, we utilized the dietary intervention of BRBs combined with a mouse model to demonstrate microbial changes by examining associated alterations in the gut microbiota, especially its functional metabolites. Results showed that BRB consumption changed As-induced gut microbial alterations through restoring and modifying the gut microbiome, including its composition, functions and metabolites. A number of functional metabolites in addition to bacterial genera were significantly altered, which may be linked to the effects of BRBs on arsenic exposure. Results of the present study suggest functional interactions between dietary administration of black raspberries and As exposure through the lens of the gut microbiota, and modulation of the gut microbiota and its functional metabolites could contribute to effects of administration of BRBs on As toxicity.

Whole-transcriptome sequencing revealed differentially expressed mRNAs and non-coding RNAs played crucial roles in NiONPs-induced liver fibrosis

Nickel oxide nanoparticles (NiONPs) induced liver fibrosis, while its mechanisms associated with transcriptome remained unclear. This study aimed to investigate the roles of differentially expressed (DE) messenger RNAs (mRNAs) and non-coding RNAs (ncRNAs) in NiONPs-induced liver fibrosis, and further confirm whether JNK/c-Jun pathway enriched by the DE RNAs was involved in the regulation of the disease. A liver fibrosis rat model was established by intratracheal perfusion of NiONPs twice a week for 9 weeks. Whole-transcriptome sequencing was applied to obtain expression profiles of mRNAs, long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs) in the model rat and control liver tissues. Comparing the RNA expression profiles of the model and control liver tissues, we identified 324 DE mRNAs, 129 DE lncRNAs, 24 DE miRNAs and 33 DE circRNAs, and the potential interactions among them were revealed by constructing two co-expression networks, including lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA networks. Using RT-qPCR, we verified the sequencing results of some RNAs in the networks and obtained similar expression profiles, indicating our sequencing results were reliable and referable. Through Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, we predicted the biological functions and signaling pathways potentially related to NiONPs-induced liver fibrosis, such as "positive regulation of JNK cascade", "inflammatory response", "transcription factor binding", and MAPK, Wnt, PI3K-Akt signaling pathways. JNK/c-Jun pathway, a subclass of MAPK signal, was selected for further investigation because it was significantly enriched by fibrosis-related DE genes and activated in animal models. In vitro, we detected the cytotoxicity of NiONPs on LX-2 cells and treated the cells with 5 μg/ml NiONPs for 12 h. The results showed NiONPs induced the up-regulated protein expression of fibrotic factors collagen-1a1 (Col-1a1) and matrix metalloproteinas2 (MMP2) and JNK/c-Jun pathway activation. While these effects were reversed after JNK/c-Jun pathway was blocked by SP600125 (JNK pathway inhibitor), indicating the pathway was involved in NiONPs-induced excessive collagen formation. In conclusion, our results revealed the DE mRNAs and ncRNAs played crucial roles in NiONPs-induced liver fibrosis, and JNK/c-Jun pathway mediated the development of the disease.

Targeting endoplasmic reticulum stress-the responder to lipotoxicity and modulator of non-alcoholic fatty liver diseases

INTRODUCTION

Endoplasmic reticulum (ER) stress occurs with aberrant lipid accumulation and resultant adverse effects and widely exists in nonalcoholic fatty liver disease (NAFLD). It triggers the unfolded protein response (UPR) to restore ER homeostasis and actively participates in NAFLD pathological processes, including hepatic steatosis, inflammation, hepatocyte death, and fibrosis. Such acknowledges drive the discovery of novel NAFLD biomarker and therapeutic targets and the development of ER-stress targeted NAFLD drugs.

AREAS COVERED

This article discusses and updates the role of ER stress and UPR in NAFLD, the underlying action mechanism, and especially their full participation in NAFLD pathophysiology. It characterizes key molecular targets useful for the prevention and treatment of NAFLD and highlights the recent ER stress-targeted therapeutic strategies for NAFLD.

EXPERT OPINION

Targeting ER Stress is a valuable and promising strategy for NAFLD treatment, but its smooth translation into clinical application still requires better clarification of the different UPR patterns in diverse NAFLD physiological states. Further understanding of the distinct effects of these various patterns on NAFLD, the thresholds deciding their final impacts, and their actions via non-liver tissues and cells would be of great help to develop a precise and effective therapy for NAFLD. [Figure: see text].

[Modification of dietary patterns in patients with non-alcoholic steatohepatitis]

AIM

To assess efficacy of dietary patterns modification with the use of specialized food in patients with non-alcoholic steatohepatitis (NASH).

MATERIALS AND METHODS

We developed new specialized food (SPP2) based on literature data on the role of dietary patterns in pathogenesis of NASH. It contained -3 PUFAs, soluble dietary fiber, phospholipids, -lipoic acid, coenzyme Q10, L-carnitine, complex of vitamins. Patients with NASH (per EASL guidelines), were invited to participate in the study and were randomly assigned to receive either isocaloric diet (ICD) alone (based on the results of indirect calorimetry Cosmed, Italy) or isocaloric diet with specialized food (2 portions of SPP2 a day), for 14 days. Repeated examinations of body composition with phase angle analysis (InBody, Republic of Korea) and blood chemistry were performed at baseline (BL) and after 14 days (EOT). The patients were advised to follow usual physical activity during the study. Non-parametric statistics was used to compare BL and EOT characteristics in the groups.

RESULTS

The groups did not differ by age, proportion of females, and baseline characteristics of body composition. Adherence to the diet was 87.5% in the ICD group and 88.2% in the ICD+SPP group (p=0.65). Compliance with the use of SPP was 100%. In the ICD+SPP group significant reduction of body weight was achieved (117.530.1 kg initially, vs 114.928.8 kg at EOT; p=0.007), whereas in the ICD group it was not statistically significant (106.722.1 kg at BL vs 104.016.8 kg at EOT, respectively; p=0.07). In contrast to the ICD group, in those who received ICD+SPP significant decrease in cholesterol (5.31.3 mmol/L at BL vs 4.61.3 mmol/L at EOT; p=0.003), LDL (3.71.0 mmol/L vs 3.31.0 mmol/L, respectively; p=0.009), alkaline phosphatase (132.699.1 vs 112.087.0 U/L; p=0.04), GGT (54.533.2 vs 37.519.7 U/L; p=0.04), insulin resistance index (6.13.2 vs 3.21.5, respectively; p=0.04) was detected.

CONCLUSION

Modification of dietary patterns with the use of a specialized food in combination with low-calorie diet allows achieving significant reduction of weight and improve lipid and carbohydrate metabolism, reduce severity of cholestasis in patients with NASH.

Cholesterol accumulation in hepatocytes mediates IRE1/p38 branch of endoplasmic reticulum stress to promote nonalcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD), based on the elevating obesity incidence, is one of the major health issue worldwide. Transition from NAFLD to non-alcoholic steatohepatitis (NASH) is driven by increased apoptosis and is relevant to higher morbidity rates. In regard to limited understanding on cholesterol mediated hepatocyte alterations in NALFD/NASH transition, we investigated endoplasmic reticulum (ER) stress and related apoptosis. Our findings suggest that cholesterol upregulates ER stress and enhances C/EBP homologous protein (CHOP) either in hypercholesterolemic rabbits or in hepatocytes treated with liposome-cholesterol complex. Mechanistically, cholesterol accumulation in hepatocytes activates IRE1/p38 branch of ER stress, stimulating CHOP levels. In liver tissues of cholesterol fed rabbits, α-tocopherol supplementation decreased IRE1/p38/CHOP activation and prevented NASH development. Thus, our study provides a critical role of hepatocyte cholesterol in inducing IRE1/p38/CHOP pathway and suggests novel candidates for therapeutic targets against NASH.

Delta-Tocopherol Suppresses the Dysfunction of Thermogenesis due to Inflammatory Stimulation in Brown Adipocytes

Brown adipose tissue (BAT) functions as a radiator for thermogenesis and helps maintain body temperature and regulate metabolism. Inflammatory signals have been reported to inhibit PGC-1α activation and UCP1-mediated thermogenesis in brown adipocytes. Inflammation is mainly caused by cell hypertrophy and macrophage invasion due to obesity, and invading macrophages secrete inflammatory cytokines, including TNF-α, IL1β, and IL6, which suppress the thermogenesis in BAT. Tocopherol is a lipid-soluble vitamin with anti-inflammatory effects is expected to contribute to the suppression of inflammation in adipose tissue. In this study, we investigated the protective effect of tocopherols, α-tocopherol (α-toc) and δ-tocopherol (δ-toc), against brown adipocyte inflammation and thermogenesis dysfunction.Inflammatory stimulation by TNF-α, a major inflammatory cytokine, significantly decreased the protein expression levels of UCP1 and PGC-1α in rat primary brown adipocytes. The pre-incubation of α-toc or δ-toc significantly suppressed the decrease in UCP1 and PGC-1α expression and lipid accumulation. Additionally, α-toc and δ-toc suppress the induction of ERK1/2 gene expression, implying that an antiinflammatory effect is involved in this protective effect. We fed mice a high-fat diet for 16 weeks and investigated the effects of α-toc and δ-toc in the diet. Intake of α-toc and δ-toc significantly suppressed weight gain and hypertrophy of brown adipocytes. Our results suggest that α-toc and δ-toc suppress the dysfunction of thermogenesis in brown adipocytes due to inflammation and contribute to the treatment of obesity and obesity-related metabolic diseases.

Role of vitamin E in the treatment of non-alcoholic steatohepatitis

Non-alcoholic steatohepatitis (NASH), a severe form of non-alcoholic fatty liver disease (NAFLD), can progress to cirrhosis, hepatocellular carcinoma (HCC), and hepatic failure/liver transplantation. Indeed, NASH will soon be the leading cause of HCC and liver transplantation. Lifestyle intervention represents the cornerstone of NASH treatment, but it is difficult to sustain. However, no pharmacotherapies for NASH have been approved. Oxidative stress has been implicated as one of the key factors in the pathogenesis of NASH. Systematic reviews with meta-analyses have confirmed that vitamin E reduces transaminase activities and may resolve NASH histopathology without improving hepatic fibrosis. However, vitamin E is not recommended for the treatment of NASH in diabetes, NAFLD without liver biopsy, NASH cirrhosis, or cryptogenic cirrhosis. Nevertheless, vitamin E supplementation may improve clinical outcomes in patients with NASH and bridging fibrosis or cirrhosis. Further studies are warranted to confirm such effects of vitamin E and that it would reduce overall mortality/morbidity without increasing the incidence of cardiovascular events. Future clinical trials of the use of vitamin E in combination with other anti-fibrotic agents may demonstrate an additive or synergistic therapeutic effect. Vitamin E is the first-line pharmacotherapy for NASH, according to the consensus of global academic societies.