Taurine prevents ethanol-induced apoptosis mediated by mitochondrial or death receptor pathways in liver cells

A functional chicken-liver hydrolysate-based supplement ameliorates alcohol liver disease via regulation of antioxidation, anti-inflammation, and antiapoptosis

Tons of broiler livers are produced yearly in Taiwan but always considered waste. Our team has successfully patented and characterized a chicken-liver hydrolysate (CLH) with several biofunctions. Chronic alcohol consumption causes hepatosteatosis or even hepatitis, cirrhosis, and cancers. This study was to investigate the hepatoprotection of CLH-based supplement (GBHP01™) against chronic alcohol consumption. Results showed that GBHP01™ could reduce (p < .05) enlarged liver size, lipid accumulation/steatosis scores, and higher serum AST, ALT, γ-GT, triglyceride, and cholesterol levels induced by an alcoholic liquid diet. GBHP01™ reduced liver inflammation and apoptosis in alcoholic liquid-diet-fed mice via decreasing TBARS, interleukin-6, interleukin-1β, and tumor necrosis factor-α levels, increasing reduced GSH/TEAC levels and activities of SOD, CAT and GPx, as well as downregulating CYP2E1, BAX/BCL2, Cleaved CASPASE-9/Total CASPASE-9 and Active CASPASE-3/Pro-CASPASE-3 (p < .05). Furthermore, GBHP01™ elevated hepatic alcohol metabolism (ADH and ALDH activities) (p < .05). In conclusion, this study prove the hepatoprotection of GBHP01™ against alcohol consumption.

Insights of mitochondrial involvement in alcoholic fatty liver disease

Alcoholic liver disease (ALD) is a global concern affecting most of the population and leading to the development of end-stage liver disease. Metabolic alterations due to increased alcohol consumption surge the hepatic accumulation of lipids and develop into a severe form of alcoholic steatohepatitis (ASH), depending on age and the consumption rate. The mitochondria in the hepatocyte actively regulate metabolic homeostasis and are disrupted in ALD pathogenesis. The increased NADH upon ethanol metabolism inhibits the mitochondrial oxidation of fatty acids, alters oxidative phosphorylation, and favors de novo lipogenesis. The higher mitochondrial respiration in early ALD increases free radical generation, whereas mitochondrial respiration is uncoupled in chronic ALD, affecting the cellular energy status. The defective glutathione importer due to excessive cholesterol loading and low adenosine triphosphate accounts for additional oxidative stress leading to hepatocyte apoptosis. The defective mitochondrial transcription machinery and sirtuins function in ALD affect mitochondrial function and biogenesis. The metabolites of ethanol metabolism epigenetically alter the gene expression profile of hepatic cell populations by modulating the promoters and sirtuins, aiding hepatic fibrosis and inflammation. The defect in mitophagy increases the accumulation of megamitochondria in hepatocytes and attracts immune cells by releasing mitochondrial damage-associated molecular patterns to initiate hepatic inflammation and ASH progression. Thus, maintaining mitochondrial lipid homeostasis and antioxidant capacity pharmacologically could provide a better outcome for ALD management.

Taurine Protects against the Fatty Liver Hemorrhagic Syndrome in Laying Hens through the Regulation of Mitochondrial Homeostasis

Metabolic-associated fatty liver disease (MAFLD) is a chronic liver disease caused by fat deposition in the liver of humans and mammals, while fatty liver hemorrhagic syndrome (FLHS) is a fatty liver disease in laying hens which can increase the mortality and cause severe economic losses to the laying industry. Increasing evidence has shown a close relationship between the occurrence of fatty liver disease and the disruption of mitochondrial homeostasis. Studies have proven that taurine can regulate hepatic fat metabolism, reduce hepatic fatty deposition, inhibit oxidative stress, and alleviate mitochondrial dysfunction. However, the mechanisms by which taurine regulates mitochondrial homeostasis in hepatocytes need to be further studied. In this study, we determined the effects and mechanisms of taurine on high-energy low-protein diet-induced FLHS in laying hens and in cultured hepatocytes in free fatty acid (FFA)-induced steatosis. The liver function, lipid metabolism, antioxidant capacity, mitochondrial function, mitochondrial dynamics, autophagy, and biosynthesis were detected. The results showed impaired liver structure and function, mitochondrial damage and dysfunction, lipid accumulation, and imbalance between mitochondrial fusion and fission, mitochondrial autophagy, and biosynthesis in both FLHS hens and steatosis hepatocytes. Taurine administration can significantly inhibit the occurrence of FLHS, protect mitochondria in hepatocytes from disease induced by lipid accumulation and FFA, up-regulate the expression levels of Mfn1, Mfn2, Opa1, LC3I, LC3II, PINK1, PGC-1α, Nrf1, Nrf2, and Tfam, and down-regulate the expression levels of Fis1, Drp1, and p62. In conclusion, taurine can protect laying hens from FLHS through the regulation of mitochondrial homeostasis, including the regulation of mitochondrial dynamics, autophagy, and biosynthesis.

Dietary taurine supplementation counteracts deoxynivalenol-induced liver injury via alleviating oxidative stress, mitochondrial dysfunction, apoptosis, and inflammation in piglets

Deoxynivalenol (DON), as a widespread Fusarium mycotoxin in cereals, food products, and animal feed, is detrimental to both human and animal health. The liver is not only the primary organ responsible for DON metabolism but also the principal organ affected by DON toxicity. Taurine is well known to display various physiological and pharmacological functions due to its antioxidant and anti-inflammatory properties. However, the information regarding taurine supplementation counteracting DON-induced liver injury in piglets is still unclear. In our work, twenty-four weaned piglets were subjected to four groups for a 24-day period, including the BD group (a basal diet), the DON group (3 mg/kg DON-contaminated diet), the DON+LT group (3 mg/kg DON-contaminated diet + 0.3% taurine), and the DON+HT group (3 mg/kg DON-contaminated diet + 0.6% taurine). Our findings indicated that taurine supplementation improved growth performance and alleviated DON-induced liver injury, as evidenced by the reduced pathological and serum biochemical changes (ALT, AST, ALP, and LDH), especially in the group with the 0.3% taurine. Taurine could counteract hepatic oxidative stress in piglets exposed to DON, as it reduced ROS, 8-OHdG, and MDA concentrations and improved the activity of antioxidant enzymes. Concurrently, taurine was observed to upregulate the expression of key factors involved in mitochondrial function and the Nrf2 signaling pathway. Furthermore, taurine treatment effectively attenuated DON-induced hepatocyte apoptosis, as verified through the decreased proportion of TUNEL-positive cells and regulation of the mitochondria-mediated apoptosis pathway. Finally, the administration of taurine was able to reduce liver inflammation due to DON, by inactivating the NF-κB signaling pathway and declining the production of pro-inflammatory cytokines. In summary, our results implied that taurine effectively improved DON-induced liver injury. The underlying mechanism should be that taurine restored mitochondrial normal function and antagonized oxidative stress, thereby reducing apoptosis and inflammatory responses in the liver of weaned piglets.

Hepatoprotective Effects of Taurine Against Cadmium-Induced Liver Injury in Female Mice

Cadmium (Cd), a heavy metal contaminant, seriously threatens human and animal health. Taurine (Tau) has been used against hepatotoxicity caused by different environmental toxins. However, it has not been elucidated whether Tau exerts its protective function against Cd-induced hepatotoxicity. The aim of this study was thus to evaluate the ameliorative function of Tau (500 mg/kg body weight intraperitoneally) on Cd-induced (2 mg/kg body weight intraperitoneally) liver toxicity in mice for 14 days. The histopathologic and ultrastructure changes as well as alterations in indexes related to liver function, antioxidant biomarkers, inflammatory, and apoptosis were evaluated. The results showed that Tau alleviated the vacuolar degeneration, nuclear condensation, mitochondria swelling, and cristae lysis of hepatocytes induced by Cd. In addition, Tau treatment significantly reduced the ALT, AST levels in serum, and inflammatory factor TNF-α and IL-1β in liver tissue. Furthermore, Tau treatment decreased the Bax/Bcl-2 ratio and cleaved caspase-3 protein expression levels. Taken together, these observations demonstrate that Tau has an important hepatic protective function against the inflammation and apoptosis induced by Cd.

Metabolic signature of HepaRG cells exposed to ethanol and tumor necrosis factor alpha to study alcoholic steatohepatitis by LC-MS-based untargeted metabolomics

Despite the high prevalence of alcoholic liver disease, its identification and characterization remain poor, especially in early stages such as alcoholic fatty liver disease and alcoholic steatohepatitis. This latter implies diagnostic difficulties, few therapeutic options and unclear mechanisms of action. To elucidate the metabolic alterations and pinpoint affected biochemical pathways, alcoholic steatohepatitis was simulated in vitro by exposing HepaRG cells to ethanol (IC₁₀, 368 mM) and tumor necrosis factor alpha (TNF-α, 50 ng/mL) for 24 h. This combined exposure was compared to solely ethanol-exposed as well as -nonexposed cells. Four different metabolomics platforms were used combining liquid chromatography, high-resolution mass spectrometry and drift tube ion mobility to elucidate both intracellular and extracellular metabolic alterations. Some of the key findings include the influence of TNF-α in the upregulation of hepatic triglycerides and the downregulation of hepatic phosphatidylethanolamines and phosphatidylcholines. S-Adenosylmethionine showed to play a central role in the progression of alcoholic steatohepatitis. In addition, fatty acyl esters of hydroxy fatty acid (FAHFA)-containing triglycerides were detected for the first time in human hepatocytes and their alterations showed a potentially important role during the progression of alcoholic steatohepatitis. Ethoxylated phosphorylcholine was identified as a potential new biomarker of ethanol exposure.

Taurine protects against perfluorooctanoic acid-induced hepatotoxicity via inhibition of oxidative stress, inflammatory, and apoptotic pathways

We are constantly encountering with low doses of chemicals in everyday life rather than toxic doses at a time. So, ongoing low-dose exposures of environmental chemicals commonly encountered are very likely to cause an adverse health effects. Perfluorooctanoic acid (PFOA) is frequently used for production of an array of consumer products and industrial processes. The present study evaluated the underlying mechanisms of PFOA-induced liver damage and also potential protection by taurine. Male Wistar rats were exposed to PFOA alone and in combination with taurine (25, 50, and 100 mg/kg/day) by gavage for 4 weeks. Liver function tests as well as histopathological examinations were studied. Also, oxidative stress markers, mitochondrial function, and nitric oxide (NO) production in liver tissues were measured. In addition, the expression of apoptosis-related genes (caspase-3, Bax, and Bcl-2), inflammation-associated genes (TNF-α, IL-6, NF-B), and c-Jun-N-terminal kinase (JNK) were evaluated. Taurine significantly reversed serum biochemical and histopathological alterations in the liver tissue following exposure to PFOA (10 mg/kg/day). Similarly, taurine alleviated mitochondrial oxidative damage-induced by PFOA in the liver tissue. An increased Bcl2: Bax ratio with decrees in the expression level of caspase-3, and decreased expression of inflammatory markers (TNF-α and IL-6), NF-B, and JNK were also observed following the administration of taurine. These findings suggest a protective role of taurine against PFOA-induced hepatotoxicity via the inhibition of oxidative stress, inflammation, and apoptosis.

A Key Metabolic Regulator of Bone and Cartilage Health

Taurine, a cysteine-derived zwitterionic sulfonic acid, is a common ingredient in energy drinks and is naturally found in fish and other seafood. In humans, taurine is produced mainly in the liver, and it can also be obtained from food. In target tissues, such as the retina, heart, and skeletal muscle, it functions as an essential antioxidant, osmolyte, and antiapoptotic agent. Taurine is also involved in energy metabolism and calcium homeostasis. Taurine plays a considerable role in bone growth and development, and high-profile reports have demonstrated the importance of its metabolism for bone health. However, these reports have not been collated for more than 10 years. Therefore, this review focuses on taurine-bone interactions and covers recently discovered aspects of taurine's effects on osteoblastogenesis, osteoclastogenesis, bone structure, and bone pathologies (e.g., osteoporosis and fracture healing), with due attention to the taurine-cartilage relationship.

Versatile Triad Alliance: Bile Acid, Taurine and Microbiota

Taurine is the most abundant free amino acid in the body, and is mainly derived from the diet, but can also be produced endogenously from cysteine. It plays multiple essential roles in the body, including development, energy production, osmoregulation, prevention of oxidative stress, and inflammation. Taurine is also crucial as a molecule used to conjugate bile acids (BAs). In the gastrointestinal tract, BAs deconjugation by enteric bacteria results in high levels of unconjugated BAs and free taurine. Depending on conjugation status and other bacterial modifications, BAs constitute a pool of related but highly diverse molecules, each with different properties concerning solubility and toxicity, capacity to activate or inhibit receptors of BAs, and direct and indirect impact on microbiota and the host, whereas free taurine has a largely protective impact on the host, serves as a source of energy for microbiota, regulates bacterial colonization and defends from pathogens. Several remarkable examples of the interaction between taurine and gut microbiota have recently been described. This review will introduce the necessary background information and lay out the latest discoveries in the interaction of the co-reliant triad of BAs, taurine, and microbiota.

Oyster broth concentrate and its major component taurine alleviate acute alcohol‐induced liver damage

Our previous study showed that oyster hydrolysate (OH) protected against the liver damage caused by a single instance of ethanol (EtOH) binge drinking. Oyster broth concentrate (OBC) was discovered in the process of searching for a different substance derived from oysters (Crassostrea gigas) with economic value. OBC is a by‐product of boiling oysters at 95°C for 3 min. In this study, we investigated the effects of OBC and its major component taurine on blood and liver tissues obtained from a single‐EtOH‐binge‐drinking mouse model. The preadministration of OBC enhanced EtOH metabolism by increasing the activities of alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), and catalase. In addition, the preadministration of OBC reduced cytochrome P450 2E1 (CYP2E1) activity, reactive oxygen species (ROS) generation, Ca²⁺ concentrations, apoptotic signals, and inflammatory mediators in liver tissues. The reduction of apoptotic and inflammatory signals by OBC resulted from the downregulation of endoplasmic reticulum (ER) stress molecules and NF‐κB activity. Taurine administration showed similar effects to OBC. These results show that OBC protected against acute EtOH‐induced liver damage through the action of taurine. Our findings suggest that OBC could be an economically valuable substance and a functional food with hepatoprotective effects.

Metabolic Signature of Ethanol-Induced Hepatotoxicity in HepaRG Cells by Liquid Chromatography-Mass Spectrometry-Based Untargeted Metabolomics

Alcoholic liver disease is highly prevalent but poorly identified and characterized, leading to knowledge gaps, which impairs early diagnosis. Excessive alcohol consumption is known to alter lipid metabolism, followed by progressive intracellular lipid accumulation, resulting in alcoholic fatty liver disease. In this study, HepaRG cells were exposed to ethanol at IC₁₀ and 1/10 IC₁₀ for 24 and 48 h. Metabolic alterations were investigated intra- and extracellularly with liquid chromatography-high-resolution mass spectrometry. Ion mobility was added as an extra separation dimension for untargeted lipidomics to improve annotation confidence. Distinctive patterns between exposed and control cells were consistently observed, with intracellular upregulation of di- and triglycerides, downregulation of phosphatidylcholines and phosphatidylethanolamines, sphingomyelins, and S-adenosylmethionine, among others. Several intracellular metabolic patterns could be related to changes in the extracellular environment, such as increased intracellular hydrolysis of sphingomyelins, leading to increased phosphorylcholine secretion. Carnitines showed alterations depending on the size of their carbon chain, which highlights the interplay between β-oxidation in mitochondria and peroxisomes. Potential new biomarkers of ethanol-induced hepatotoxicity have been observed, such as ceramides with a sphingadienine backbone, octanoylcarnitine, creatine, acetylcholine, and ethoxylated phosphorylcholine. The combination of the metabolic fingerprint and footprint enabled a comprehensive investigation of the pathophysiology behind ethanol-induced hepatotoxicity.

Urinary metabolomics study of vancomycin-associated nephrotoxicity based on ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry

Drug-induced nephrotoxicity is widespread and seriously affects human health. Vancomycin is a classical glycopeptide antibiotic. Vancomycin is widely used for severe infections caused by Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus but its obvious nephrotoxicity affects the safety of its clinical application. However, the etiology of vancomycin induced kidney injury is not well understood. This study aimed to explore the potential mechanism of vancomycin-induced nephrotoxicity in rats. Vancomycin (400 mgkg^-1) was used to establish kidney injury models in rats. A metabonomic approach was employed using ultra-performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) to delineate metabolic alterations. As a result, 15, 22, and 37 biomarkers were identified in urine samples from the treatment group compared to the control model on D2, D4, and D7, respectively. Changes in the levels of these metabolites indicated that amino acid metabolism and energy metabolism were disturbed in rats with vancomycin-associated nephrotoxicity. This study revealed the kidney effect of vancomycin, which may provide novel and promising research approaches to vancomycin-induced renal toxicity.

Suppression of endoplasmic reticulum stress-associated pathways and hepatocyte apoptosis participates in the attenuation of betulinic acid on alcohol-provoked liver injury in mice

BA protects against alcohol-induced liver damage through the alleviation of oxidative stress and suppression of ERS-induced apoptosis.

Determination of metabolic phenotype and potential biomarkers in the liver of heroin addicted mice with hepatotoxicity

BACKGROUND

Heroin is a semi-synthetic opioid that is commonly abused drugs in the world. It can cause hepatic injury and lead to multiple organs dysfunction to its addicts. Only a few reports exist on the metabolic changes and mechanisms in the liver of heroin-addicted mice with hepatic injury.

METHODS

Twelve adult male Kunming mice (30-40 g) were divided into two groups randomly. The mice in the heroin-addicted group were injected subcutaneously in the first ten days with an increased dosage of heroin from 10 mg/kg to 55 mg/kg. The dosage was then stabilized at 55 mg/kg for three days. The control group was injected with the same amount of saline in the same manner. The hepatic injury was confirmed through the combination of histopathological observation and aminotransferase (AST) and alanine aminotransferase (ALT) determination. The withdrawal symptoms were recorded and used for assessment of heroin addiction. Eventually, liver metabolic biomarkers of heroin-addicted mice with hepatotoxicity were measured using UHPLC-MS/MS.

RESULTS

Biochemical analysis and histopathological observation showed that heroin-addicted mice had a liver injury. The liver metabolites of heroin-addicted mice changed significantly. Metabonomics analysis revealed 41 metabolites in the liver of addicted heroin mice as biomarkers involving 34 metabolic pathways. Among them, glutathione metabolism, taurine and hypotaurine metabolism, vitamin B2 metabolism, riboflavin metabolism, and single-carbon metabolism pathways were markedly dispruted.

CONCLUSIONS

Heroin damages the liver and disrupts the liver's metabolic pathways. Glutathione, taurine, riboflavin, 4-pyridoxate, folic acid, and methionine are important metabolic biomarkers, which may be key targets of heroin-induced liver damage. Thus, this study provides an in-depth understanding of the mechanisms of heroin-induced hepatotoxicity and potential biomarkers of liver damage.

Taurine attenuates valproic acid-induced hepatotoxicity via modulation of RIPK1/RIPK3/MLKL-mediated necroptosis signaling in mice

Valproic acid (VPA) is known as a common drug in seizure and bipolar disorders treatment. Hepatotoxicity is the most important complication of VPA. Taurine (Tau), an amino acid, has antioxidant effects. The present research was conducted to evaluate the protective mechanisms of Tau on VPA-induced liver injury, especially focusing on the necroptosis signaling pathway. The sixty-four male NMRI mice were divided into eight groups with eight animals per each. The experiment groups pretreated with Tau (250, 500, 1000 mg/kg) and necrostatine-1 (Nec-1, 1.8 mg/kg) and then VPA (500 mg/kg) was administered for 14 consecutive days. The extent of VPA-induced hepatotoxicity was confirmed by elevated ALP (alkaline phosphatase), AST (aspartate aminotransferase), ALT (alanine aminotransferase) levels, and histological changes as steatosis, accumulation of erythrocytes, and inflammation. Additionally, VPA significantly induced oxidative stress in the hepatic tissue by increasing ROS (reactive oxygen species) production and lipid peroxidation level along with decreasing GSH (glutathione). Hepatic TNF-α (tumor necrosis factor) level, mRNA and protein expression of RIPK1 (receptor-interacting protein kinase 1), RIPK3, and MLKL (mixed lineage kinase domain-like pseudokinase) were upregulated. Also, the phosphorylation of MLKL and RIPK3 increased in the VPA group. Tau could effectively reverse these events. Our data suggest which necroptosis has a key role in the toxicity of VPA through TNF-α-mediated RIPK1/RIPK3/MLKL signaling and oxidative stress. Our findings suggest that Tau protects the liver tissue against VPA toxicity via inhibiting necroptosis signaling pathway mediated by RIPK1/RIPK3/MLKL and suppressing oxidative stress, and apoptosis.

The insect peptide CopA3 blocks programmed cell death by directly binding caspases and inhibiting their proteolytic activation

Caspases play essential roles in apoptotic processes, which is necessary for cellular homeostasis. However, over-activation of caspases and subsequent excessive apoptosis is considered a main cause of Parkinson's disease and liver diseases. Here, we found that the insect-derived peptide, CopA3, which has shown antiapoptotic effects in many apoptosis models, directly binds to caspases. The resulting complexes do not dissociate during denaturing polyacrylamide gel electrophoresis, as evidenced by a distinct shift in the migration of caspase reflecting an increase in their molecular weight. Surface plasmon resonance and experiment using cysteine-substituted mutants of CopA3 collectively revealed that binding of CopA3 to caspases is dependent on an internal cysteine residue. Notably, CopA3 binding significantly inhibited proteolytic activation of downstream caspases by upstream caspases. In summary, the demonstration that CopA3 directly binds to caspases and inhibits their activating cleavage suggests a possible therapeutic approach for treating human diseases resulting from uncontrolled apoptosis.

A comprehensive review of natural products to fight liver fibrosis: Alkaloids, terpenoids, glycosides, coumarins and other compounds

The discovery of drugs to treat liver fibrosis has long been a challenge over the past decades due to its complicated pathogenesis. As a primary approach for drug development, natural products account for 30% of clinical drugs used for disease treatment. Therefore, natural products are increasingly important for their medicinal value in liver fibrosis therapy. In this part of the review, special focus is placed on the effect and mechanism of natural compounds, including alkaloids, terpenoids, glycosides, coumarins and others. A total of 36 kinds of natural compounds demonstrate significant antifibrotic effects in various liver fibrosis models in vivo and in hepatic stellate cells (HSCs) in vitro. Revealing the mechanism will provide further basis for clinical conversion, as well as accelerate drug discovery. The mechanism was further summarized with the finding of network regulation by several natural products, such as oxymatrine, paeoniflorin, ginsenoside Rg1 and taurine. Moreover, there are still improvements needed in investigating clinical efficacy, determining mechanisms, and combining applications, as well as semisynthesis and modification. Therefore, natural products area promising resource for agents that protect against liver fibrosis.

Taurine attenuates gossypol-induced apoptosis of C2C12 mouse myoblasts via the GPR87-AMPK/AKT signaling

Gossypol, a toxic polyphenol extracted from cotton seeds, is hazardous to human and animal health. Taurine is considered as an essential or semi-essential amino acid and has diverse cytoprotective effects. This study was aimed to investigate the protective effect and molecular mechanism of taurine against apoptosis of C2C12 mouse myoblasts induced by gossypol. C2C12 mouse myoblasts were exposed to gossypol (0, 1 nM, 10 nM, 100 nM, 1 μM, and 10 μM). Cell numbers were rapidly decreased with increasing concentrations of gossypol. Gossypol significantly induced apoptosis, decreased Bcl2 expression, and increased the protein levels of Bax and the cleaved caspase 3. Taurine (0.24 mM) treatment largely rescued the cell number decreased by gossypol, attenuated gossypol-induced cell apoptosis. GPR87 knockdown abolished the inhibition by taurine of cell apoptosis. Furthermore, GPR87 overexpression attenuated cell apoptosis induced by gossypol. Both taurine treatment and GPR87 overexpression stimulated AKT phosphorylation but inhibited AMPK phosphorylation, whereas gossypol had the opposite effects. Taurine treatment promoted GPR87 expression and subcellular localization and partially rescued the inhibition of gossypol on this expression. In summary, these data reveal that taurine attenuates gossypol-induced apoptosis of C2C12 mouse myoblasts via the GPR87-AMPK/AKT signaling.

Taurine attenuates isoproterenol-induced H9c2 cardiomyocytes hypertrophy by improving antioxidative ability and inhibiting calpain-1-mediated apoptosis

Pathological cardiac hypertrophy is ultimately accompanied by cardiomyocyte apoptosis. Apoptosis mainly related to calpain-1-mediated apoptotic pathways. Studies had proved that taurine can maintain heart health through antioxidation and antiapoptotic functions, but the effect of taurine on cardiac hypertrophy is still unclear. This study aimed to determine whether taurine could inhibit calpain-1-mediated mitochondria-dependent apoptotic pathways in isoproterenol (ISO)-induced hypertrophic cardiomyocytes. We found that taurine could inhibit the increase in cell surface area and reduce the protein expression levels of the hypertrophic markers atrial natriuretic peptide, brain natriuretic polypeptide, and β-myosin heavy chain. Taurine also reduced ROS, intracellular Ca²⁺ overload and mitochondrial membrane potential. Moreover, taurine inhibited cardiomyocyte apoptosis by decreasing the protein expression of calpain-1, Bax, t-Bid, cytosolic cytochrome c, Apaf-1, cleaved caspase-9 and cleaved caspase-3 and by enhancing calpastatin and Bcl-2 protein expression. Calpain-1 small interfering RNA transfection results showed similar antiapoptotic effects as the taurine prevention group. However, compared with the two treatments, taurine inhibited the expression of cleaved caspase-9 more significantly. Therefore, we believe that taurine prevents ISO-induced H9c2 cardiomyocyte hypertrophy by inhibiting oxidative stress, intracellular Ca²⁺ overload, the calpain-1-mediated mitochondria-dependent apoptotic pathway and cleaved caspase-9 levels.

Taurine prevents cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers

The calpain-1-activated apoptotic pathway plays a key role in right ventricular hypertrophy (RVH). Taurine has been shown to attenuate apoptosis by inhibiting calpain activity. This experiment aimed to determine whether taurine could prevent RVH by inhibiting the calpain-1/cytochrome c apoptotic pathway. The broilers were given 1% taurine dissolved in drinking water and were raised at 10 °C ~ 12 °C from day 21 to day 42. At 21 d, 28 d, 35 d and 42 d, the right ventricular (RV) tissues were collected. Increased RVH index, angiotensin II, norepinephrine and atrial natriuretic peptide mRNA expression were reduced by taurine in the broiler RVs. Taurine obviously inhibited cardiomyocyte apoptosis via maintaining the mitochondrial membrane potential and decreased the activation of caspase-9 and caspase-3 in the broiler RVs. The antioxidant assay demonstrated that taurine enhanced the activities of superoxide dismutase, total antioxidant capacity and glutathione peroxidase and the glutathione/glutathione disulfide ratio. Western blot results revealed that taurine also downregulated the expression of calpain-1 and cytosolic cytochrome c while upregulating the expression of Bcl-2/Bax and mitochondrial cytochrome c in broiler cardiomyocytes during RVH. In summary, we found that taurine could enhance cardiomyocyte antioxidant ability and further prevented cardiomyocyte apoptosis by inhibiting the calpain-1/cytochrome c pathway during RVH in broilers.

The influence of taurine and L-carnitine on 6 β-hydroxycortisol/cortisol ratio in human urine of healthy volunteers

Background Cytochrome P450s (CYPs, EC 1.14.14.1) are the main enzymes of drug metabolism. The functional significance of CYPs also includes the metabolism of foreign chemicals and endogenic biologically active compounds. The CYP3A4 isoform contributes to the metabolism of about half of all marketed medicinal preparations. The aim of this study was to investigate the effects of two biologically active compounds: 2-aminoethane-sulfonic acid (taurine) and 3-hydroxy-4-trimethylaminobutyrate (L-carnitine) on urinary 6β-hydroxycortisol/cortisol (6β-OHC/cortisol) metabolic ratio as a biomarker of the CYP3A4 activity of healthy volunteers. Taurine is used for the treatment of chronic heart failure and liver disease. Cardiologists, nephrologists, neurologists, gerontologists in addition to the main etiopathogenetic therapies, use L-carnitine. The quantification of the 6β-OHC/cortisol metabolic ratio as a biomarker of CYP3A4 activity in human urine was used for the assessment of CYP3A4 catalytic activity as a non-invasive test. Methods The study included 18 healthy male volunteers (aged from 18 to 35 years old). The volunteers took taurine in a dose of 500 mg twice a day or L-carnitine in a dose of 2.5 mL 3 times a day for 14 consecutive days. The test drug was given 20 min before meals. The collection of urine samples was performed before and after 3, 7, 10, and 14 days after taurine intake. The metabolic ratio of 6β-OHC/cortisol in morning spot urine samples was studied by the liquid chromatography/mass spectroscopy (LC/MS) method. Results The ratio of 6-6β-OHC/cortisol was used as a biomarker to study the taurine and L-carnitine influence on CYP3A4 metabolism of cortisol. The ratio of urinary 6β-OCH/cortisol in the morning urine samples of volunteers before the beginning of taurine therapy (baseline ratio) was 2.71 ± 0.2. Seven days after the administration of taurine in a dose of 500 mg twice a day, the 6β-OCH/cortisol ratio was 3.3 ± 0.2, which indicated the increased catalytic activity of CYP3A4 towards cortisol. As for the L-carnitine supplementation, analysis of the 6β-OCH/cortisol ratio in the urine for 14 days did not show any significant changes in this baseline ratio, indicating the lack of L-carnitine influence on the catalytic activity of CYP3A4 to cortisol. Conclusions The results obtained demonstrated the influence of taurine on 6β-OCH/cortisol metabolic ratio as a biomarker of CYP3A4 catalytic activity to cortisol. L-carnitine did not affect the activity of CYP3A4. The lack of a clinically meaningful effect of L-carnitine was established.

A Hepatoprotective Effect of a Hot Water Extract from Loliolus beka Gray Meat Against H2O2-Induced Oxidative Damage in Hepatocytes

Here, we investigated the hepatoprotective effect of a hot water extract from Loliolus beka gray meat (LBMH) containing plentiful taurine in H₂O₂-induced oxidative stress in hepatocytes. LBMH potently scavenged the 2,2-azino-bis(3-ethylbenzthiazoline)-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and exhibited the good reducing power and the oxygen radical absorbance capacity (ORAC) value. Also, LBMH improved the cell viability against H₂O₂-induced hepatic damage in cultured hepatocytes by reducing intracellular reactive oxygen species (ROS) production. In addition, LBMH inhibited apoptosis via a reduction in sub-G₁ cell population, as well as inhibition of apoptotic body formation from H₂O₂-induced oxidative damage in hepatocytes. Moreover, LBMH regulated the expression levels of Bax, a pro-apoptotic molecule and Bcl-2, an anti-apoptotic molecule in H₂O₂-treated hepatocytes. Additionally, pre-treatment with LBMH increased the expression of heme oxygenase 1 (HO-1), which is a hepatoprotective enzyme, by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) in H₂O₂-treated hepatocytes. Taken together, LBMH may be useful as a food ingredient for treatment of liver disease by regulating the Nrf2/HO-1 signal pathway.

Tau-TCHF Inhibits Spleenic Apoptosis via PI3K-Akt Signaling Pathway in Chickens

Taurine plays an important role in improving immunity, regulating cell proliferation and differentiation, apoptosis and so on. Traditional Chinese herb formula (TCHF) is a wealth of medicine materials for diseases control. There are many studies on Chinese herb formula in inducing cell apoptosis, differentiation and improving animal immunity. The factors in phosphatidylinositol 3-kinase/Protein Kinase (PI3K-Akt) signaling pathway are central regulators of normal cells, which integrates extra-cellular signals into cells and activates affects cell activities including cell proliferation, differentiation and apoptosis. We find the key factors (PIK3CA, PDPK1, AKT1, MDM2, ITGA2B, ITGB1, FAK and p53) in PI3K-Akt signaling pathway by RNA-Seq analysis in our previous research. The overall goal of this study to investigate the influence of taurine TCHF (Tau-TCHF) on cell proliferation, differentiation and apoptosis by estimating the factors above. The layers were fed with normal diet plus 1% of Tau-TCHF and the control group with normal diet to 42 days old. The spleen tissue samples from individual layers were used to analyze the influence of Tau-TCHF on the factors PIK3CA, PDPK1, AKT1, MDM2, ITGA2B, ITGB1, FAK and p53 in PI3K-Akt signaling pathway. The levels of transcription and protein expression of various factors were assessed by quantitative PCR (qPCR) and Western Blot. The results showed that the transcription levels of itgb1, fak, pik3ca, akt1 and mdm2 on 42-day-old chicken spleen tissues were increased significantly in Tau-TCHF group comparing with control group (P < 0.01); the transcription levels of itga2b, pdpk1 and p53 were no significant difference (P > 0.05). The protein levels of PDPK1 and AKT (Ser437) were increased significantly (P < 0.05), but ITGA2B, ITGB1, FAK, PIK3CA, AKT1, MDM2 and p53 had no significant difference (P > 0.05). The results suggest that Tau-TCHF may influence proliferation and differentiation of chickens spleen via regulating PI3K-Akt signaling pathway. And Tau-TCHF may be provided as feed additives in improving the immunity of animals. AKT (Ser473) and PDPK1 may be considered as further targets to study mechanism of Tau-TCHF on anti-apoptosis via PI3K-Akt signaling pathway.