Mitochondrial dysfunction and mitochondrion-targeted therapeutics in liver diseases

Liver-Targeted Delivery Based on Prodrug: Passive and Active Approaches

BACKGROUND

The liver, a central organ in human metabolism, is often the primary target for drugs. However, conditions such as viral hepatitis, cirrhosis, non-alcoholic fatty liver disease (NAFLD), and hepatocellular carcinoma (HCC) present substantial health challenges worldwide. Existing treatments, which suffer from the non-specific distribution of drugs, frequently fail to achieve desired efficacy and safety, risking unnecessary liver harm and systemic side effects.

PURPOSE

The aim of this review is to synthesize the latest progress in the design of liver-targeted prodrugs, with a focus on passive and active targeting strategies, providing new insights into the development of liver-targeted therapeutic approaches.

METHODS

This study conducted an extensive literature search through databases like Google Scholar, PubMed, Web of Science, and China National Knowledge Infrastructure (CNKI), systematically collecting and selecting recent research on liver-targeted prodrugs. The focus was on targeting mechanisms, including the Enhanced Permeability and Retention (EPR) effect, the unique microenvironment of liver cancer, and active targeting through specific transporters and receptors.

RESULTS

Active targeting strategies achieve precise drug delivery by binding specific ligands to liver surface receptors. Passive targeting takes advantage of the EPR effect and tumor characteristics to enrich drugs in liver tumors. The review details successful cases of using small molecule ligands, peptides, antibodies and nanoparticles as drug carriers.

CONCLUSION

Liver-targeted prodrug strategies show great potential in enhancing the efficacy of drug treatment and reducing side effects for liver diseases. Future research should balance the advantages and limitations of both targeting strategies, focusing on optimizing drug design and targeting efficiency, especially for clinical application. In-depth research on liver-specific receptors and the development of innovative targeting molecules are crucial for advancing the field of liver-targeted prodrugs.

Pharmacological mechanism of natural antidepressants: The role of mitochondrial quality control

BACKGROUND

Depression is a mental illness characterized by persistent sadness and a reduced capacity for pleasure. In clinical practice, SSRIs and other medications are commonly used for therapy, despite their various side effects. Natural products present distinct advantages, including synergistic interactions among multiple components and targeting multiple pathways, suggesting their tremendous potential in depression treatment. Imbalance in mitochondrial quality control (MQC) plays a significant role in the pathology of depression, emphasizing the importance of regulating MQC as a potential intervention strategy in addressing the onset and progression of depression. However, the role and mechanism through which natural products regulate MQC in depression treatments still need to be comprehensively elucidated, particularly in clinical and preclinical settings.

PURPOSE

This review was aimed to summarize the findings of recent studies and outline the pharmacological mechanisms by which natural products modulate MQC to exert antidepressant effects. Additionally, it evaluated current research limitations and proposed new strategies for future preclinical and clinical applications in the depression domain.

METHODS

To study the main pharmacological mechanisms underlying the regulation of MQC by natural products in the treatment of depression, we conducted a thorough search across databases such as PubMed, Web of Science, and ScienceDirect databases to classify and summarize the relationship between MQC and depression, as well as the regulatory mechanisms of natural products.

RESULTS

Numerous studies have shown that irregularities in the MQC system play an important role in the pathology of depression, and the regulation of the MQC system is involved in antidepressant treatments. Natural products mainly regulate the MQC system to induce antidepressant effects by alleviating oxidative stress, balancing ATP levels, promoting mitophagy, maintaining calcium homeostasis, optimizing mitochondrial dynamics, regulating mitochondrial membrane potential, and enhancing mitochondrial biogenesis.

CONCLUSIONS

We comprehensively summarized the regulation of natural products on the MQC system in antidepressants, providing a unique perspective for the application of natural products within antidepressant therapy. However, extensive efforts are imperative in clinical and preclinical investigations to delve deeper into the mechanisms underlying how antidepressant medications impact MQC, which is crucial for the development of effective antidepressant treatments.

The Roles of NFR2-Regulated Oxidative Stress and Mitochondrial Quality Control in Chronic Liver Diseases

Chronic liver disease (CLD) affects a significant portion of the global population, leading to a substantial number of deaths each year. Distinct forms like non-alcoholic fatty liver disease (NAFLD) and alcoholic fatty liver disease (ALD), though they have different etiologies, highlight shared pathologies rooted in oxidative stress. Central to liver metabolism, mitochondria are essential for ATP production, gluconeogenesis, fatty acid oxidation, and heme synthesis. However, in diseases like NAFLD, ALD, and liver fibrosis, mitochondrial function is compromised by inflammatory cytokines, hepatotoxins, and metabolic irregularities. This dysfunction, especially electron leakage, exacerbates the production of reactive oxygen species (ROS), augmenting liver damage. Amidst this, nuclear factor erythroid 2-related factor 2 (NRF2) emerges as a cellular protector. It not only counters oxidative stress by regulating antioxidant genes but also maintains mitochondrial health by overseeing autophagy and biogenesis. The synergy between NRF2 modulation and mitochondrial function introduces new therapeutic potentials for CLD, focusing on preserving mitochondrial integrity against oxidative threats. This review delves into the intricate role of oxidative stress in CLD, shedding light on innovative strategies for its prevention and treatment, especially through the modulation of the NRF2 and mitochondrial pathways.

Phosphatidylserine decarboxylase downregulation in uric acid‑induced hepatic mitochondrial dysfunction and apoptosis

The molecular mechanisms underlying uric acid (UA)-induced mitochondrial dysfunction and apoptosis have not yet been elucidated. Herein, we investigated underlying mechanisms of UA in the development of mitochondrial dysfunction and apoptosis. We analyzed blood samples of individuals with normal UA levels and patients with hyperuricemia. Results showed that patients with hyperuricemia had significantly elevated levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, which may indicate liver or mitochondrial damage in patients with hyperuricemia. Subsequently, lipidomic analysis of mouse liver tissue mitochondria and human liver L02 cell mitochondria was performed. Compared with control group levels, high UA increased mitochondrial phosphatidylserine (PS) and decreased mitochondrial phosphatidylethanolamine (PE) levels, whereas the expression of mitochondrial phosphatidylserine decarboxylase (PISD) that mediates PS and PE conversion was downregulated. High UA levels also inhibited signal transducer and activator of transcription 3 （STAT3） phosphorylation as well as mitochondrial respiration, while inducing apoptosis both in vivo and in vitro. Treatment with allopurinol, overexpression of PISD, and lyso-PE (LPE) administration significantly attenuated the three above-described effects in vitro. In conclusion, UA may induce mitochondrial dysfunction and apoptosis through mitochondrial PISD downregulation. This study provides a new perspective on liver damage caused by hyperuricemia.

Insights into the Role of Plasmatic and Exosomal microRNAs in Oxidative Stress-Related Metabolic Diseases

A common denominator of metabolic diseases, including type 2 diabetes Mellitus, dyslipidemia, and atherosclerosis, are elevated oxidative stress and chronic inflammation. These complex, multi-factorial diseases are caused by the detrimental interaction between the individual genetic background and multiple environmental stimuli. The cells, including the endothelial ones, acquire a preactivated phenotype and metabolic memory, exhibiting increased oxidative stress, inflammatory gene expression, endothelial vascular activation, and prothrombotic events, leading to vascular complications. There are different pathways involved in the pathogenesis of metabolic diseases, and increased knowledge suggests a role of the activation of the NF-kB pathway and NLRP3 inflammasome as key mediators of metabolic inflammation. Epigenetic-wide associated studies provide new insight into the role of microRNAs in the phenomenon of metabolic memory and the development consequences of vessel damage. In this review, we will focus on the microRNAs related to the control of anti-oxidative enzymes, as well as microRNAs related to the control of mitochondrial functions and inflammation. The objective is the search for new therapeutic targets to improve the functioning of mitochondria and reduce oxidative stress and inflammation, despite the acquired metabolic memory.

Mitochondria: It is all about energy

Mitochondria play a key role in both health and disease. Their function is not limited to energy production but serves multiple mechanisms varying from iron and calcium homeostasis to the production of hormones and neurotransmitters, such as melatonin. They enable and influence communication at all physical levels through interaction with other organelles, the nucleus, and the outside environment. The literature suggests crosstalk mechanisms between mitochondria and circadian clocks, the gut microbiota, and the immune system. They might even be the hub supporting and integrating activity across all these domains. Hence, they might be the (missing) link in both health and disease. Mitochondrial dysfunction is related to metabolic syndrome, neuronal diseases, cancer, cardiovascular and infectious diseases, and inflammatory disorders. In this regard, diseases such as cancer, Alzheimer's, Parkinson's, amyotrophic lateral sclerosis (ALS), chronic fatigue syndrome (CFS), and chronic pain are discussed. This review focuses on understanding the mitochondrial mechanisms of action that allow for the maintenance of mitochondrial health and the pathways toward dysregulated mechanisms. Although mitochondria have allowed us to adapt to changes over the course of evolution, in turn, evolution has shaped mitochondria. Each evolution-based intervention influences mitochondria in its own way. The use of physiological stress triggers tolerance to the stressor, achieving adaptability and resistance. This review describes strategies that could recover mitochondrial functioning in multiple diseases, providing a comprehensive, root-cause-focused, integrative approach to recovering health and treating people suffering from chronic diseases.

Mitochondrial respiratory chain activity is associated with severity, corticosteroid response and prognosis of alcoholic hepatitis

BACKGROUND AND AIMS

Little is known about the extent of mitochondrial respiratory chain (MRC) activity dysfunction in patients with alcoholic hepatitis (AH). We aimed to assess the hepatic MRC activity in AH patients and its potential impact on the severity and prognosis of this life-threatening liver disease.

METHODS

MRC complexes were measured in liver biopsies of 98 AH patients (non-severe, 17; severe, 81) and in 12 histologically normal livers (NL). Severity was assessed according to Maddrey's Index and MELD score. Corticosteroid response rate and cumulative mortality were also evaluated.

RESULTS

The activity of the five MRC complexes was markedly decreased in the liver of AH patients compared with that of NL subjects, being significantly lower in patients with severe AH than in those with non-severe AH. There was a negative correlation between the activity of all MRC complexes and the severity of AH. Interestingly, only complex I and III activities showed a significant positive correlation with the corticosteroid response rate and a significant negative correlation with the mortality rate at all-time points studied. In a multivariate regression analysis, besides the MELD score and the corticosteroid response rate, complex I activity was significantly associated with 3-month mortality (OR = 6.03; p = 0.034) and complex III activity with 6-month mortality (OR = 4.70; p = 0.041) in AH patients.

CONCLUSION

Our results indicate that MRC activity is markedly decreased in the liver of AH patients, and, particularly, the impairment of MRC complexes I and III activity appears to have a significant impact on the clinical outcomes of patients with AH.

Psoralea corylifolia L.: a comprehensive review of its botany, traditional uses, phytochemistry, pharmacology, toxicology, quality control and pharmacokinetics

Psoralea corylifolia L. (PCL), referred to as "Bu-gu-zhi" in Chinese, has great medicinal values since ancient times. PCL is the dried ripe fruit of Psoralea corylifolia L., which has been widely used in traditional Chinese medicine (TCM) for the treatment of kidney-yang deficiency, enuresis and urinary frequency, chills and pain of the waist and knees, dawn diarrhea and vitiligo. In this paper, a systematic of the botany, traditional uses, phytochemistry, pharmacology, toxicology, quality control and pharmacokinetics of PCL was presented, along with future research directions. According to the results, PCL contains approximately 163 chemical components, including coumarins, flavonoids, monoterpene phenols, benzofurans, glycosides, lipids, fatty acids, and volatile oils. PCL and its active ingredients have a variety of pharmacological activities, such as anti-inflammatory, antibacterial, antiviral, antioxidant, antitumor, antiosteoporosis, cardioprotective, neuroprotective, and immunomodulatory. Further study of quality control standards and potential mechanisms of PCL is also needed. In addition, more toxicological studies will also contribute to the progress of clinical trials.

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 PARK7 Improves Acetaminophen-Induced Acute Liver Injury by Orchestrating Mitochondrial Quality Control and Metabolic Reprogramming

Mitochondrial dysfunction and oxidative stress are considered to be key events in acetaminophen (APAP)-induced acute liver injury. Mitochondrial quality control, including mitophagy and mitochondrial synthesis, can restore mitochondrial homeostasis and thus protect the liver. The role of PARK7, a mitochondrial stress protein, in regulating mitochondrial quality control in APAP-induced hepatotoxicity is unclear. In this study, L02 cells, AML12 cells and C57/BL6 mice were each used to establish models of APAP-induced acute liver injury. PARK7 was silenced in vitro by lentiviral transfection and knocked down in vivo by AAV adeno-associated virus. Changes in cell viability, apoptosis, reactive oxygen species (ROS) level, serum enzyme activity and pathological features were evaluated after APAP treatment. Western blotting, real-time PCR, immunofluorescence, electron microscopy and Seahorse assays were used to detect changes in key indicators of mitochondrial quality control. The results showed that APAP treatment decreased cell viability and increased the apoptosis rate, ROS levels, serum enzyme activity, pathological damage and PARK7 expression. PARK7 silencing or knockdown ameliorated APAP-induced damage to the cells and liver. Furthermore, PARK7 silencing enhanced mitophagy, increased mitochondrial synthesis, and led to a switch from oxidative phosphorylation to glycolysis. Taken together, these results suggest that PARK7 is involved in APAP-induced acute liver injury by regulating mitochondrial quality control and metabolic reprogramming. Therefore, PARK7 may be a promising therapeutic target for APAP-induced liver injury.

Epigallocatechin-3-gallate Mo nanoparticles (EGM NPs) efficiently treat liver injury by strongly reducing oxidative stress, inflammation and endoplasmic reticulum stress

Drug-induced liver injury (DILI) is a serious clinical disease associated with reactive oxygen species (ROS) burst and subsequent inflammatory responses. However, traditional treatments were limited by low efficacy and serious side effects due to the special liver structure. Here, we developed a molybdenum (Mo)-based nanoparticles, EGM NPs, after overall consideration of the pathophysiology of DILI and the advantages of nanodrugs. It demonstrated that EGM NPs treated acetaminophen (APAP)-induced DILI by scavenging ROS and inhibiting inflammation. EGM NPs effectively scavenged various ROS and reduced cell apoptosis at the cellular level. More importantly, EGM NPs can treat APAP-induced DILI in vivo, reducing the levels of liver function indicators in mice with liver injury, scaling down the area of hepatocyte necrosis and successfully inhibiting endoplasmic reticulum (ER) stress in the liver. EGM NPs also showed a certain anti-inflammatory effect by reducing infiltration of macrophages, decreasing pro-inflammatory factors and inhibiting the expression levels of inducible nitric oxide synthase (NOS2) and myeloperoxidase (MPO). Collectively, our findings suggest that EGM NPs-based nanotherapeutic is a novel strategy for the treatment of DILI.

Anticancer activity of oleanolic acid and its derivatives modified at A-ring and C-28 position

Oleanolic acid (OA) is a five-ring triterpenoid compound, which is widely present in plants. Due to a wide range of pharmacological activities, oleanolic acid has attracted more and more attention. However, oleanolic acid is insoluble in water and has low bioavailability, which limits its clinical application. In this review, we focus on summarizing the anti-cancer activity and mechanism of the A ring or C-28 carboxyl modified derivatives of OA since 2015, to determine the strength of its anti-cancer effectiveness and evaluate whether it could be used as a clinical anti-cancer drug.

Mitochondria Matter: Systemic Aspects of Nonalcoholic Fatty Liver Disease (NAFLD) and Diagnostic Assessment of Liver Function by Stable Isotope Dynamic Breath Tests

The liver plays a key role in systemic metabolic processes, which include detoxification, synthesis, storage, and export of carbohydrates, lipids, and proteins. The raising trends of obesity and metabolic disorders worldwide is often associated with the nonalcoholic fatty liver disease (NAFLD), which has become the most frequent type of chronic liver disorder with risk of progression to cirrhosis and hepatocellular carcinoma. Liver mitochondria play a key role in degrading the pathways of carbohydrates, proteins, lipids, and xenobiotics, and to provide energy for the body cells. The morphological and functional integrity of mitochondria guarantee the proper functioning of β-oxidation of free fatty acids and of the tricarboxylic acid cycle. Evaluation of the liver in clinical medicine needs to be accurate in NAFLD patients and includes history, physical exam, imaging, and laboratory assays. Evaluation of mitochondrial function in chronic liver disease and NAFLD is now possible by novel diagnostic tools. "Dynamic" liver function tests include the breath test (BT) based on the use of substrates marked with the non-radioactive, naturally occurring stable isotope 13C. Hepatocellular metabolization of the substrate will generate 13CO2, which is excreted in breath and measured by mass spectrometry or infrared spectroscopy. Breath levels of 13CO2 are biomarkers of specific metabolic processes occurring in the hepatocyte cytosol, microsomes, and mitochondria. 13C-BTs explore distinct chronic liver diseases including simple liver steatosis, non-alcoholic steatohepatitis, liver fibrosis, cirrhosis, hepatocellular carcinoma, drug, and alcohol effects. In NAFLD, 13C-BT use substrates such as α-ketoisocaproic acid, methionine, and octanoic acid to assess mitochondrial oxidation capacity which can be impaired at an early stage of disease. 13C-BTs represent an indirect, cost-effective, and easy method to evaluate dynamic liver function. Further applications are expected in clinical medicine. In this review, we discuss the involvement of liver mitochondria in the progression of NAFLD, together with the role of 13C-BT in assessing mitochondrial function and its potential use in the prevention and management of NAFLD.