AMPK As A Target in Rare Diseases

Does β-Hydroxy-β-Methylbutyrate Have Any Potential to Support the Treatment of Duchenne Muscular Dystrophy in Humans and Animals?

Skeletal muscle is the protein reservoir of our body and an important regulator of glucose and lipid homeostasis. The dystrophin gene is the largest gene and has a key role in skeletal muscle construction and function. Mutations in the dystrophin gene cause Duchenne and Becker muscular dystrophy in humans, mice, dogs, and cats. Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular condition causing progressive muscle weakness and premature death. β-hydroxy β-methylbutyrate (HMB) prevents deleterious muscle responses under pathological conditions, including tumor and chronic steroid therapy-related muscle losses. The use of HMB as a dietary supplement allows for increasing lean weight gain; has a positive immunostimulatory effect; is associated with decreased mortality; and attenuates sarcopenia in elderly animals and individuals. This study aimed to identify some genes, metabolic pathways, and biological processes which are common for DMD and HMB based on existing literature and then discuss the consequences of that interaction.

AMPK and its Activator Berberine in the Treatment of Neurodegenerative Diseases

Neurodegenerative disorders are heterogeneous diseases associated with either acute or progressive neurodegeneration, causing the loss of neurons and axons in the central nervous system (CNS), showing high morbidity and mortality, and there are only a few effective therapies. Here, we summarized that the energy sensor adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), and its agonist berberine can combat the common underlying pathological events of neurodegeneration, including oxidative stress, neuroinflammation, mitochondrial disorder, glutamate excitotoxicity, apoptosis, autophagy disorder, and disruption of neurovascular units. The abovementioned effects of berberine may primarily depend on activating AMPK and its downstream targets, such as the mammalian target of rapamycin (mTOR), sirtuin1 (SIRT1), nuclear factor erythroid-2 related factor-2 (Nrf2), nuclear factor-κB (NF-κB), phosphoinositide 3-kinase/protein kinase B (PI3K/Akt), nicotinamide adenine dinucleotide (NAD+), and p38 mitogen-activated protein kinase (p38 MAPK). It is hoped that this review will provide a strong basis for further scientific exploration and development of berberine's therapeutic potential against neurodegeneration.

dBMHCC: A comprehensive hepatocellular carcinoma (HCC) biomarker database provides a reliable prediction system for novel HCC phosphorylated biomarkers

Hepatocellular carcinoma (HCC), which is associated with an absence of obvious symptoms and poor prognosis, is the second leading cause of cancer death worldwide. Genome-wide molecular biology studies should provide biological insights into HCC development. Based on the importance of phosphorylation for signal transduction, several protein kinase inhibitors have been developed that improve the survival of cancer patients. However, a comprehensive database of HCC-related phosphorylated biomarkers (HCCPMs) and novel HCCPMs prediction platform has been lacking. We have thus constructed the dBMHCC databases to provide expression profiles, phosphorylation and drug information, and evidence type; gathered information on HCC-related pathways and their involved genes as candidate HCC biomarkers; and established a system for evaluating protein phosphorylation and HCC-related biomarkers to improve the reliability of biomarker prediction. The resulting dBMHCC contains 611 notable HCC-related genes, 234 HCC-related pathways, 17 phosphorylation-related motifs and their 255 corresponding protein kinases, 5955 HCC biomarkers, and 1077 predicted HCCPMs. Methionine adenosyltransferase 2B (MAT2B) and acireductone dioxygenase 1 (ADI1), which regulate HCC development and hepatitis C virus infection, respectively, were among the top 10 HCCPMs predicted by dBMHCC. Platelet-derived growth factor receptor alpha (PDGFRA), which had the highest evaluation score, was identified as the target of one HCC drug (Regorafenib), five cancer drugs, and four non-cancer drugs. dBMHCC is an open resource for HCC phosphorylated biomarkers, which supports researchers investigating the development of HCC and designing novel diagnosis methods and drug treatments. Database URL:http://predictor.nchu.edu.tw/dBMHCC.

Metabolic disturbance in Korean red ginseng-induced "Shanghuo" (excessive heat)

ETHNOPHARMACOLOGICAL RELEVANCE

Northeast China is one of the Korean Red Ginseng (KRG) producing areas. As a health care product, KRG is popular amongst Chinese people. However, few studies have reported the side effects of overusing KRG.

AIM OF THE STUDY

The main purpose of this study is to explore the mechanism of Korean Red Ginseng (KRG)-induced "Shanghuo" (excessive heat).

MATERIALS AND METHODS

After the baseline characteristics were evaluated, 30 healthy volunteers were administrated with 3g of KRG for 10-16 days and diagnosed with "Shanghuo". The volunteers prior to the administration of KRG were considered as the control group. The volunteers after being diagnosed with "Shanghuo" (excessive heat) were considered as "Shanghuo" group. The two groups were assessed by the tests of serum metabolic products, Succinate Dehydrogenase (SDH) activity, and mRNA expressions of adenosine monophosphate (AMP)-activated protein kinase (AMPK), PPARG Coactivator 1 Alpha (PGC-1α) and Nuclear Respiratory Factor 1 (NRF1).

RESULTS

Most of the serum metabolites in the "Shanghuo" group were increased compared with the control group, from high to low including serine, valine, heptacosane, xylose, glycerol 1-monostearate, d-glucose, 3-pyridinol, glyceryl palmitate, urea, phosphoric acid, glycerol, stearic acid, palmitic acid, cyclohexaneacetic acid. Only cholesterol was significantly reduced, The SDH activity and the mRNA expressions of AMPK, PGC-1α and NRF1 were significantly increased in the "Shanghuo" group.

CONCLUSIONS

Overconsumption of KRG could induce "Shanghuo", which has a close relationship with an accelerated TCA cycle and the increased AMPK activity.

Intracellular cholesterol accumulation and coenzyme Q10 deficiency in Familial Hypercholesterolemia

Familial Hypercholesterolemia (FH) is an autosomal co-dominant genetic disorder characterized by elevated low-density lipoprotein (LDL) cholesterol levels and increased risk for premature cardiovascular disease. Here, we examined FH pathophysiology in skin fibroblasts derived from FH patients harboring heterozygous mutations in the LDL-receptor. Fibroblasts from FH patients showed a reduced LDL-uptake associated with increased intracellular cholesterol levels and coenzyme Q₁₀ (CoQ₁₀) deficiency, suggesting dysregulation of the mevalonate pathway. Secondary CoQ₁₀ deficiency was associated with mitochondrial depolarization and mitophagy activation in FH fibroblasts. Persistent mitophagy altered autophagy flux and induced inflammasome activation accompanied by increased production of cytokines by mutant cells. All the pathological alterations in FH fibroblasts were also reproduced in a human endothelial cell line by LDL-receptor gene silencing. Both increased intracellular cholesterol and mitochondrial dysfunction in FH fibroblasts were partially restored by CoQ₁₀ supplementation. Dysregulated mevalonate pathway in FH, including increased expression of cholesterogenic enzymes and decreased expression of CoQ₁₀ biosynthetic enzymes, was also corrected by CoQ₁₀ treatment. Reduced CoQ₁₀ content and mitochondrial dysfunction may play an important role in the pathophysiology of early atherosclerosis in FH. The diagnosis of CoQ₁₀ deficiency and mitochondrial impairment in FH patients may also be important to establish early treatment with CoQ₁₀.

Skeletal Muscle Metabolism in Duchenne and Becker Muscular Dystrophy-Implications for Therapies

The interactions between nutrition and metabolism and skeletal muscle have long been known. Muscle is the major metabolic organ—it consumes more calories than other organs—and therefore, there is a clear need to discuss these interactions and provide some direction for future research areas regarding muscle pathologies. In addition, new experiments and manuscripts continually reveal additional highly intricate, reciprocal interactions between metabolism and muscle. These reciprocal interactions include exercise, age, sex, diet, and pathologies including atrophy, hypoxia, obesity, diabetes, and muscle myopathies. Central to this review are the metabolic changes that occur in the skeletal muscle cells of muscular dystrophy patients and mouse models. Many of these metabolic changes are pathogenic (inappropriate body mass changes, mitochondrial dysfunction, reduced adenosine triphosphate (ATP) levels, and increased Ca²⁺) and others are compensatory (increased phosphorylated AMP activated protein kinase (pAMPK), increased slow fiber numbers, and increased utrophin). Therefore, reversing or enhancing these changes with therapies will aid the patients. The multiple therapeutic targets to reverse or enhance the metabolic pathways will be discussed. Among the therapeutic targets are increasing pAMPK, utrophin, mitochondrial number and slow fiber characteristics, and inhibiting reactive oxygen species. Because new data reveals many additional intricate levels of interactions, new questions are rapidly arising. How does muscular dystrophy alter metabolism, and are the changes compensatory or pathogenic? How does metabolism affect muscular dystrophy? Of course, the most profound question is whether clinicians can therapeutically target nutrition and metabolism for muscular dystrophy patient benefit? Obtaining the answers to these questions will greatly aid patients with muscular dystrophy.

Potential roles of AMP-activated protein kinase in liver regeneration in mice with acute liver injury

Liver regeneration post severe liver injury is crucial for the recovery of hepatic structure and function. The energy sensor AMP‑activated protein kinase (AMPK) has a crucial role in the regulation of nutrition metabolism in addition to other energy‑intensive physiological and pathophysiological processes. Cellular proliferation requires intensive energy and nutrition support, therefore the present study investigated whether AMPK is involved in liver regeneration post carbon tetrachloride (CCl4)‑induced acute hepatic injury. The experimental data indicated that phosphorylation level of AMPK increased 48 h post‑CCl4 exposure, which was accompanied with upregulation of proliferating cell nuclear antigen (PCNA) and recovery of alanine aminotransferase (ALT) level. Pretreatment with the AMPK inhibitor compound C had no obvious effects on ALT elevation in plasma and histological abnormalities in liver 24 h post CCl4 exposure. However, treatment with compound C 24 h post CCl4 exposure significantly suppressed CCl4‑induced AMPK phosphorylation, PCNA expression and ALT recovery. These data suggest that endogenous AMPK was primarily activated at the regeneration stage in mice with CCl4‑induced acute liver injury and may function as a positive regulator in liver regeneration.

CAF cellular glycolysis: linking cancer cells with the microenvironment

Cancers have long being hallmarked as cells relying heavily on their glycolysis for energy generation in spite of having functional mitochondria. The metabolic status of the cancer cells have been revisited time and again to get better insight into the overall carcinogenesis process which revealed the apparent crosstalks between the cancer cells with the fibroblasts present in the tumour microenvironment. This review focuses on the mechanisms of transformations of normal fibroblasts to cancer-associated fibroblasts (CAF), the participation of the CAF in tumour progression with special interest to the role of CAF cellular glycolysis in the overall tumorigenesis. The fibroblasts, when undergoes the transformation process, distinctly switches to a more glycolytic phenotype in order to provide the metabolic intermediates necessary for carrying out the mitochondrial pathways of ATP generation in cancer cells. This review will also discuss the molecular mechanisms responsible for this metabolic make over promoting glycolysis in CAF cells. A thorough investigation of the pathways and molecules involved will not only help in understanding the process of activation and metabolic reprogramming in CAF cells but also might open up new targets for cancer therapy.