Adenosine protects cardiomyocytes against acrolein-induced cardiotoxicity by enhancing mitochondrial homeostasis, antioxidant defense, and autophagic flux via ERK-activated FoxO1 upregulation.

Acrolein is a ubiquitous gaseous air pollutant and endogenous toxicant, which poses strong risk for oxidative stress-related diseases such as cardiovascular disease. Adenosine has been identified as potential therapeutic agent for age-related cardiovascular disease, while the molecular mechanisms underlying its cardioprotection remain elusive. In the present study, we investigated the myocardial protective effects and the mechanism of adenosine on acrolein-induced toxicity in H9c2 cells and primary neonatal rat cardiomyocytes. We found that acrolein caused apoptosis of cardiomyocytes resulting from oxidative damage, autophagy defect, and mitochondrial dysfunction, as evidenced by loss of mitochondrial membrane potential, impairment of mitochondrial biogenesis, dynamics, and oxidative phosphorylation, decrease of mitochondrial deoxyribonucleic acid (mtDNA) copy number and adenosine 5'-triphosphate (ATP) production. Adenosine pretreatment protected against acrolein-induced cardiotoxicity by maintaining mitochondrial homeostasis, activating the phase II detoxifying enzyme system, promoting autophagic flux, and alleviating mitochondrial-dependent apoptosis. We further demonstrated that the up-regulation of forkhead box protein O1 (FoxO1) mediated by extracellular regulated protein kinases (ERK) activation contributes to the cardioprotection of adenosine. These results expand the application of adenosine in cardioprotection to preventing myocardial damages induced by environmental pollutant acrolein exposure, and uncover the adenosine-ERK-FoxO1 axis as the underlying mechanism mediating the protection of mitochondrial homeostasis, Nrf2-mediated antioxidant defense and autophagic flux, shedding light on the better understanding about the pathological mechanism of cardiovascular disease caused by environmental pollutants and applications of adenosine in cardioprotection.

2-(3,4-dihydroxyphenyl)ethyl 3-hydroxybutanoate (HTHB) ameliorates cognitive dysfunction via modulating gut microbiota in aged senescence-accelerated mouse prone 8 (SAMP8) mice.

Numerous studies have indicated a close association between gut microbiota dysbiosis, inflammation, and cognitive impairment, highlighting their crucial role in the aging process. 2-(3,4-Dihydroxyphenyl)ethyl 3-hydroxybutanoate (HTHB), a novel derivative of hydroxytryrosol (HT), known for its metabolic and anti-inflammatory properties, was investigated for its effects on memory, inflammation, and gut microbiota in senescence-accelerated mouse prone 8 (SAMP8) mice. The study employed behavioral testing, biochemical detection and 16S RNA analysis. Results revealed that HTHB mitigated memory decline and lymphocyte aberrance, reduced inflammation in the brain cortex, intestine and peripheral system, and modulated gut microbiota dysbiosis. Interestingly, the cognitive function and serum inflammation of mice significantly correlated with differences in gut microbiota in SAMP8 mice. Furthermore, HTHB treatment exhibited an enhancement of gut barrier integrity in colon tissue in SAMP8 mice. In vitro experiments using HCT116 and DLD1 cells further evidenced that HTHB rescued the tight junction protein levels impaired by lipopolysaccharide (LPS). These finding demonstrate that HTHB effectively ameliorates cognitive dysfunction in aged mice, might by modulating gut microbiota, suppressing inflammation and promoting intestinal barrier integrity. This highlights the potential of HTHB as a therapeutic agent for age-related cognitive loss.

Sleep Deprivation Triggers Mitochondrial DNA Release in Microglia to Induce Neural Inflammation: Preventative Effect of Hydroxytyrosol Butyrate.

Sleep deprivation (SD) triggers mitochondrial dysfunction and neural inflammation, leading to cognitive impairment and mental issues. However, the mechanism involving mitochondrial dysfunction and neural inflammation still remains unclear. Here, we report that SD rats exhibited multiple behavioral disorders, brain oxidative stress, and robust brain mitochondrial DNA (mtDNA) oxidation. In particular, SD activated microglia and microglial mtDNA efflux to the cytosol and provoked brain pro-inflammatory cytokines. We observed that the mtDNA efflux and pro-inflammatory cytokines significantly reduced with the suppression of the mtDNA oxidation. With the treatment of a novel mitochondrial nutrient, hydroxytyrosol butyrate (HTHB), the SD-induced behavioral disorders were significantly ameliorated while mtDNA oxidation, mtDNA release, and NF-κB activation were remarkably alleviated in both the rat brain and the N9 microglial cell line. Together, these results indicate that microglial mtDNA oxidation and the resultant release induced by SD mediate neural inflammation and HTHB prevents mtDNA oxidation and efflux, providing a potential treatment for SD-induced mental issues.

Twin Strep-Tag Modified CPT1A Mitochondrial Membrane Chromatography in Screening Lipid Metabolism Regulators.

Mitochondrial Membrane Chromatography (MMC) is a bioaffinity chromatography technique developed to study the interaction between target proteins embedded in the mitochondrial membrane and their ligand compounds. However, the MMC stationary phases (MMSP) prepared by chemical immobilization are prone to nonspecific binding in candidate agent screening inevitably. To address these challenges, Twin Strep-Tag/Strep Tactin was employed to establish a specific affinity system in the present study. We prepared a carnitine palmitoyltransferase 1A (CPT1A) MMSP by specifically linking Strep-tactin-modified silica gel with the Twin Strep-Tag on the CPT1A-oriented mitochondrial membrane. This Twin Strep-Tag/Strep Tactin modified CPT1A/MMC method exhibited remarkably better retention behavior, longer stationary phase lifespan, and higher screening specificity compared with previous MMC systems with glutaraldehyde immobilization. We adopted the CPT1A-specific MMC system in screening CPT1A ligands from traditional Chinese medicines, and successfully identified novel candidate ligands: ononin, isoliquiritigenin, and aloe-emodin, from Glycyrrhiza uralensis Fisch and Senna tora (L.) Roxb extracts. Biological assessments illustrated that the compounds screened promote CPT1A enzyme activity without affecting CPT1A protein expression, as well as effectively reduce the lipid droplets and triglyceride levels in the high fat induction HepG2 cells. The results suggest that we have developed an MMC system, which is promising for studying the bioaffinity of mitochondrial membrane proteins to candidate compounds. This system provides a platform for a key step in mitochondrial medicine discovery, especially for bioactive molecule screening from complex herbal extracts.

α-Ketoglutarate prevents hyperlipidemia-induced fatty liver mitochondrial dysfunction and oxidative stress by activating the AMPK-pgc-1α/Nrf2 pathway.

α-Ketoglutarate (AKG), a crucial intermediate in the tricarboxylic acid cycle, has been demonstrated to mitigate hyperlipidemia-induced dyslipidemia and endothelial damage. While hyperlipidemia stands as a major trigger for non-alcoholic fatty liver disease, the protection of AKG on hyperlipidemia-induced hepatic metabolic disorders remains underexplored. This study aims to investigate the potential protective effects and mechanisms of AKG against hepatic lipid metabolic disorders caused by acute hyperlipidemia. Our observations indicate that AKG effectively alleviates hepatic lipid accumulation, mitochondrial dysfunction, and loss of redox homeostasis in P407-induced hyperlipidemia mice, as well as in palmitate-injured HepG2 cells and primary hepatocytes. Mechanistic insights reveal that the preventive effects are mediated by activating the AMPK-PGC-1α/Nrf2 pathway. In conclusion, our findings shed light on the role and mechanism of AKG in ameliorating abnormal lipid metabolic disorders in hyperlipidemia-induced fatty liver, suggesting that AKG, an endogenous mitochondrial nutrient, holds promising potential for addressing hyperlipidemia-induced fatty liver conditions.

Ginsenoside Rh4 prevents endothelial dysfunction as a novel AMPK activator.

BACKGROUND AND PURPOSE: The AMP-activated protein kinase (AMPK) signalling pathway is a desirable target for various cardiovascular diseases (CVD), while the involvement of AMPK-mediated specific downstream pathways and effective interventions in hyperlipidaemia-induced endothelial dysfunction remain largely unknown. Herein, we aim to identify an effective AMPK activator and to explore its efficacy and mechanism against endothelial dysfunction. EXPERIMENTAL APPROACH: Molecular docking technique was adopted to screen for the potent AMPK activator among 11 most common rare ginsenosides. In vivo, poloxamer 407 (P407) was used to induce acute hyperlipidaemia in C57BL/6J mice. In vitro, palmitic acid (PA) was used to induce lipid toxicity in HAEC cells. KEY RESULTS: We discovered the strongest binding of ginsenoside Rh4 to AMPKα1 and confirmed the action of Rh4 on AMPK activation. Rh4 effectively attenuated hyperlipidaemia-related endothelial injury and oxidative stress both in vivo and in vitro and restored cell viability, mitochondrial membrane potential and mitochondrial oxygen consumption rate in HAEC cells. Mechanistically, Rh4 bound to AMPKα1 and simultaneously up-regulated AKT/eNOS-mediated NO release, promoted PGC-1α-mediated mitochondrial biogenesis and inhibited P38 MAPK/NFκB-mediated inflammatory responses in both P407-treated mice and PA-treated HAEC cells. The AMPK inhibitor Compound C treatment completely abrogated the regulation of Rh4 on the above pathways and weakened the lowering effect of Rh4 on endothelial impairment markers, suggesting that the beneficial effects of Rh4 are AMPK dependent. CONCLUSION AND IMPLICATIONS: Rh4 may serve as a novel AMPK activator to protect against hyperlipidaemia-induced endothelial dysfunction, providing new insights into the prevention and treatment of endothelial injury-associated CVD.

Auricularia auricula-judae Attenuates the Progression of Metabolic Syndrome in High-Fat Diet-Induced Obese Rats: Enzymatic Pre-Digestion Technology Is Superior to Superfine Grinding Method.

Auricularia auricula-judae (AAJ) has been cultivated for food in China for centuries, and is also used as a folk medicine for the regulation of glucose and lipid metabolism. However, there are few studies on the effects of different processing technologies on the therapeutic efficacy of AAJ to date. This study investigated the effectiveness of the AAJ made by using superfine grinding and enzymatic pre-digestion technologies, respectively, in a high-fat diet obese rat model. It was found that oral administrations of two AAJ products significantly alleviated dyslipidemia by decreasing serum lipid levels and restoring liver functions. AAJ products made by using pre-digestion technology have appreciable potential to ameliorate lipid metabolic disorders over other products, possibly due to the higher levels of dietary fiber, crude polysaccharides, and total flavonoids released from AAJ during processing. By analysis of transcriptome sequencing and protein expression, it was clear that starch and sucrose metabolism and glycerolipid metabolism-related factors involved in fatty acid synthesis and metabolism in the liver of obese rats were significantly improved. This study gives further evidence that AAJ significantly ameliorates the progression of glucose and lipid metabolism in obese rats. Moreover, this study demonstrated for the first time that the pre-digestion method may be a better and more efficient processing approach for the improvement of AAJ bioavailability.

The Role of Nicotinamide Mononucleotide Supplementation in Psoriasis Treatment.

Psoriasis is one of several chronic inflammatory skin diseases with a high rate of recurrence, and its pathogenesis remains unclear. Nicotinamide mononucleotide (NMN), as an important precursor of nicotinamide adenine dinucleotide (NAD+), has been reported to be a promising agent in treating various diseases, its positive effects including those induced via its anti-inflammatory and antioxidant properties. For this reason, we have aimed to explore the possible role of NMN in the treatment of psoriasis. Psoriasis models were constructed with imiquimod (IMQ) stimulation for 5 days in vivo and with M5 treatment in keratinocyte cell lines in vitro. NMN treatment during the IMQ application period markedly attenuated excess epidermal proliferation, splenomegaly, and inflammatory responses. According to GEO databases, Sirtuin1 (SIRT1) levels significantly decreased in psoriasis patients' lesion tissues; this was also the case in the IMQ-treated mice, while NMN treatment reversed the SIRT1 decline in the mouse model. Moreover, NMN supplementation also improved the prognoses of the mice after IMQ stimulation, compared to the untreated group with elevated SIRT1 levels. In HEKa and HaCaT cells, the co-culturing of NMN and M5 significantly decreased the expression levels of proinflammation factors, the phosphorylation of NF-κB, stimulator of interferon genes (STING) levels, and reactive oxygen species levels. NMN treatment also recovered the decrease in mitochondrial membrane potential and respiration ability and reduced mtDNA in the cytoplasm, leading to the inhibition of autoimmune inflammation. The knockdown of SIRT1 in vitro eliminated the protective and therapeutic effects of NMN against M5. To conclude, our results indicate that NMN protects against IMQ-induced psoriatic inflammation, oxidative stress, and mitochondrial dysfunction by activating the SIRT1 pathway.

High-sensitivity C-reactive protein in heart failure with preserved ejection fraction: Findings from TOPCAT.

BACKGROUND: Inflammation plays a central role in the genesis and progression of heart failure with preserved ejection fraction (HFpEF). C-reactive protein (CRP) is widely used as means to assess systemic inflammation, and elevated levels of CRP have been associated with poor HF prognosis. Identification of chronic low-grade inflammation in outpatients can be performed measuring high-sensitivity CRP (hsCRP). The clinical characteristics and outcome associations of a pro-inflammatory state among outpatients with HFpEF requires further study. AIMS: Using a biomarker subset of TOPCAT-Americas (NCT00094302), we aim to characterize HFpEF patients according to hsCRP levels and study the prognostic associations of hsCRP. METHODS: hsCRP was available in a subset of 232 participants. Comparisons were performed between patients with hsCRP <2 mg/L and ≥ 2 mg/L. Cox regression models were used to study the association between hsCRP and the study outcomes. RESULTS: Compared to patients with hsCRP <2 mg/L (n = 89, 38%), those with hsCRP ≥2 mg/L (n = 143, 62%) had more frequent HF hospitalizations prior to randomization, chronic obstructive pulmonary disease, orthopnea, higher body mass index, and worse health-related quality-of-life. A hsCRP level ≥ 2 mg/L was associated with an increased risk of cardiovascular death and HF hospitalizations: hsCRP ≥2 mg/L vs <2 mg/L adjusted HR 2.36, 95%CI 1.27-4.38, P = 0.006. Spironolactone did not influence hsCRP levels from baseline to month 12: gMean ratio = 1.11, 95%CI 0.87-1.42, P = 0.39. CONCLUSIONS: A hsCRP ≥2 mg/L identified HFpEF patients with a high risk of HF events and cardiovascular mortality. Spironolactone did not influence hsCRP levels at 12 months.

Screening of CPT1A-Targeting Lipid Metabolism Modulators Using Mitochondrial Membrane Chromatography.

Carnitine palmitoyltransferase 1A (CPT1A), which resides on the mitochondrial outer membrane, serves as the rate-limiting enzyme of fatty acid ß-oxidation. Identifying the compounds targeting CPT1A warrants a promising candidate for modulating lipid metabolism. In this study, we developed a CPT1A-overexpressed mitochondrial membrane chromatography (MMC) to screen the compounds with affinity for CPT1A. Cells overexpressing CPT1A were cultured, and subsequently, their mitochondrial membrane was isolated and immobilized on amino-silica gel cross-linked by glutaraldehyde. After packing the mitochondrial membrane column, retention components of MMC were performed with LC/MS, whose analytic peaks provided structural information on compounds that might interact with mitochondrial membrane proteins. With the newly developed MMC-LC/MS approach, several Chinese traditional medicine extracts, such as Scutellariae Radix and Polygoni Cuspidati Rhizoma et Radix (PCRR), were analyzed. Five noteworthy compounds, baicalin, baicalein, wogonoside, wogonin, and resveratrol, were identified as enhancers of CPT1A enzyme activity, with resveratrol being a new agonist for CPT1A. The study suggests that MMC serves as a reliable screening system for efficiently identifying modulators targeting CPT1A from complex extracts.

Long-term simulated microgravity fosters carotid aging-like changes via Piezo1.

AIMS: Elucidating the impacts of long-term spaceflight on cardiovascular health is urgently needed in face of the rapid development of human space exploration. Recent reports including the NASA Twins Study on vascular deconditioning and aging of astronauts in spaceflight are controversial. The aims of this study were to elucidate whether long-term microgravity promotes vascular aging and the underlying mechanisms. METHODS AND RESULTS: Hindlimb unloading (HU) by tail suspension was used to simulate microgravity in rats and mice. The dynamic changes of carotid stiffness in rats during 8 weeks of HU were determined. Simulated microgravity led to carotid artery aging-like changes as evidenced by increased stiffness, thickness, fibrosis, and elevated senescence biomarkers in the HU rats. Specific deletion of the mechanotransducer Piezo1 in vascular smooth muscles significantly blunted these aging-like changes in mice. Mechanistically, mechanical stretch-induced activation of Piezo1 elevated microRNA-582-5p in vascular smooth muscle cells, with resultant enhanced synthetic cell phenotype and increased collagen deposition via PTEN/PI3K/Akt signalling. Importantly, inhibition of miRNA-582-5p alleviated carotid fibrosis and stiffness not only in HU rats but also in aged rats. CONCLUSIONS: Long-term simulated microgravity induces carotid aging-like changes via the mechanotransducer Piezo1-initiated and miRNA-mediated mechanism.

Nuclear Factor Erythroid 2 Related Factor 2 and Mitochondria Form a Mutually Regulating Circuit in the Prevention and Treatment of Metabolic Syndrome.

Significance: Metabolic syndrome (MetS) has become a major global public health problem and there is an urgent need to elucidate its pathogenesis and find more effective targets and modalities for intervention. Recent Advances: Oxidative stress and inflammation are two of the major causes of MetS-related symptoms such as insulin resistance and obesity. Nuclear factor erythroid 2 related factor 2 (Nrf2) is one of the important systems responding to oxidative stress and inflammation. As cells undergo stress, cysteines within Kelch-like ECH-associated protein 1 (Keap1) are oxidized or electrophilically modified, allowing Nrf2 to escape ubiquitination and be translocated from the cytoplasm to the nucleus, facilitating the initiation of the antioxidant transcriptional program. Meanwhile, a growing body of evidence points out a specific modulation of mitochondrial homeostasis by Nrf2. After nuclear translocation, Nrf2 activates downstream genes involved in various aspects of mitochondrial homeostasis, including mitochondrial biogenesis and dynamics, mitophagy, aerobic respiration, and energy metabolism. In turn, mitochondria reciprocally activate Nrf2 by releasing reactive oxygen species and regulating antioxidant enzymes. Critical Issues: In this review, we first summarize the interactions between Nrf2 and mitochondria in the modulation of oxidative stress and inflammation to ameliorate MetS, then propose that Nrf2 and mitochondria form a mutually regulating circuit critical to maintaining homeostasis during MetS. Future Directions: Targeting the Nrf2-mitochondrial circuit may be a promising strategy to ameliorate MetS, such as obesity, diabetes, and cardiovascular diseases.

Mitochondria as a sensor, a central hub and a biological clock in psychological stress-accelerated aging.

The theory that oxidative damage caused by mitochondrial free radicals leads to aging has brought mitochondria into the forefront of aging research. Psychological stress that encompasses many different experiences and exposures across the lifespan has been identified as a catalyst for accelerated aging. Mitochondria, known for their dynamic nature and adaptability, function as a highly sensitive stress sensor and central hub in the process of accelerated aging. In this review, we explore how mitochondria as sensors respond to psychological stress and contribute to the molecular processes in accelerated aging by viewing mitochondria as hormonal, mechanosensitive and immune suborganelles. This understanding of the key role played by mitochondria and their close association with accelerated aging helps us to distinguish normal aging from accelerated aging, correct misconceptions in aging studies, and develop strategies such as exercise and mitochondria-targeted nutrients and drugs for slowing down accelerated aging, and also hold promise for prevention and treatment of age-related diseases.

Exercise Attenuates Myocardial Ischemia-Reperfusion Injury by Regulating Endoplasmic Reticulum Stress and Mitophagy Through M2 Acetylcholine Receptor.

Aims: Adaptive changes in the heart by exercise have been shown to reduce the risk of cardiovascular disease, and M2 Acetylcholine receptor (M2AChR), a receptor abundantly present on cardiac parasympathetic nerves, is closely associated with the development of cardiovascular disease. The present study intends to investigate whether exercise can regulate endoplasmic reticulum stress (ERS) and mitophagy through M2AChR to resist myocardial ischemia-reperfusion (I/R) injury and to elucidate its mechanism of action. Results: Exercise enhanced parasympathetic nerve function and increased myocardial M2AChR protein expression in I/R rats. In addition, it promoted the protein expression of MFN2 and inhibited the expression of Drp1, Chop, PINK1/Parkin, and PERK/eIF2α/ATF4 signaling pathways, effectively reducing mitophagy, ERS, and apoptosis. At the cellular level, 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR) reduced hypoxia/reoxygenation (H/R)-induced ERS through the downregulated expression of PERK/eIF2α/ATF4 pathway proteins in H9C2 cardiomyocytes. When intervened with M2AChR inhibitors, the levels of ERS and phosphorylation levels of the PERK/eIF2α/ATF4 pathway were increased in H/R cells. Innovation and Conclusion: Exercise intervention activated the parasympathetic state in rats. It inhibited myocardial mitophagy and ERS levels, and reduced myocardial apoptosis through M2AChR, thereby resisting I/R-induced myocardial injury and improving cardiac function. Antioxid. Redox Signal. 40, 209-221.

SOX10 deficiency-mediated LAMB3 upregulation determines the invasiveness of MAPKi-resistant melanoma.

Melanoma that develops adaptive resistance to MAPK inhibitors (MAPKi) through transcriptional reprograming-mediated phenotype switching is associated with enhanced metastatic potential, yet the underlying mechanism of this improved invasiveness has not been fully elucidated. In this study, we show that MAPKi-resistant melanoma cells are more motile and invasive than the parental cells. We further show that LAMB3, a ß subunit of the extracellular matrix protein laminin-332 is upregulated in MAPKi-resistant melanoma cells and that the LAMB3-Integrin α3/α6 signaling mediates the motile and invasive phenotype of resistant cells. In addition, we demonstrate that SOX10 deficiency in MAPKi-resistant melanoma cells drives LAMB3 upregulation through TGF-ß signaling. Transcriptome profiling and functional studies further reveal a FAK/MMPs axis mediates the pro-invasiveness effect of LAMB3. Using a mouse lung metastasis model, we demonstrate LAMB3 depletion inhibits the metastatic potential of MAPKi-resistant cells in vivo. In summary, this study identifies a SOX10low/TGF-ß/LAMB3/FAK/MMPs signaling pathway that determines the migration and invasion properties of MAPKi-resistant melanoma cells and provide rationales for co-targeting LAMB3 to curb the metastasis of melanoma cells in targeted therapy.

Hydrogen: A Rising Star in Gas Medicine as a Mitochondria-Targeting Nutrient via Activating Keap1-Nrf2 Antioxidant System.

The gas molecules O2, NO, H2S, CO, and CH4, have been increasingly used for medical purposes. Other than these gas molecules, H2 is the smallest diatomic molecule in nature and has become a rising star in gas medicine in the past few decades. As a non-toxic and easily accessible gas, H2 has shown preventive and therapeutic effects on various diseases of the respiratory, cardiovascular, central nervous system, and other systems, but the mechanisms are still unclear and even controversial, especially the mechanism of H2 as a selective radical scavenger. Mitochondria are the main organelles regulating energy metabolism in living organisms as well as the main organelle of reactive oxygen species' generation and targeting. We propose that the protective role of H2 may be mainly dependent on its unique ability to penetrate every aspect of cells to regulate mitochondrial homeostasis by activating the Keap1-Nrf2 phase II antioxidant system rather than its direct free radical scavenging activity. In this review, we summarize the protective effects and focus on the mechanism of H2 as a mitochondria-targeting nutrient by activating the Keap1-Nrf2 system in different disease models. In addition, we wish to provide a more rational theoretical support for the medical applications of hydrogen.

Comparative Study of Hydroxytyrosol Acetate and Hydroxytyrosol in Activating Phase II Enzymes.

Nuclear factor E2-related factor 2 (Nrf2) is fundamental to the maintenance of redox homeostasis within cells via the regulation of a series of phase II antioxidant enzymes. The unique olive-derived phenolic compound hydroxytyrosol (HT) is recognized as an Nrf2 activator, but knowledge of the HT derivative hydroxytyrosol acetate (HTac) on Nrf2 activation remains limited. In this study, we observed that an HT pretreatment could protect the cell viability, mitochondrial membrane potential, and redox homeostasis of ARPE-19 cells against a t-butyl hydroperoxide challenge at 50 µM. HTac exhibited similar benefits at 10 µM, indicating a more effective antioxidative capacity compared with HT. HTac consistently and more efficiently activated the expression of Nrf2-regulated phase II enzymes than HT. PI3K/Akt was the key pathway accounting for the beneficial effects of HTac in ARPE-19 cells. A further RNA-Seq analysis revealed that in addition to the consistent upregulation of phase II enzymes, the cells presented distinct expression profiles after HTac and HT treatments. This indicated that HTac could trigger a diverse cellular response despite its similar molecular structure to HT. The evidence in this study suggests that Nrf2 activation is the major cellular activity shared by HTac and HT, and HTac is more efficient at activating the Nrf2 system. This supports its potential future employment in various disease management strategies.

Facile hermetic TEM grid preparation for molecular imaging of hydrated biological samples at room temperature.

Although structures of vitrified supramolecular complexes have been determined at near-atomic resolution, elucidating in situ molecular structure in living cells remains a challenge. Here, we report a straightforward liquid cell technique, originally developed for real-time visualization of dynamics at a liquid-gas interface using transmission electron microscopy, to image wet biological samples. Due to the scattering effects from the liquid phase, the micrographs display an amplitude contrast comparable to that observed in negatively stained samples. We succeed in resolving subunits within the protein complex GroEL imaged in a buffer solution at room temperature. Additionally, we capture various stages of virus cell entry, a process for which only sparse structural data exists due to their transient nature. To scrutinize the morphological details further, we used individual particle electron tomography for 3D reconstruction of each virus. These findings showcase this approach potential as an efficient, cost-effective complement to other microscopy technique in addressing biological questions at the molecular level.

Melatonin Restores Autophagic Flux by Activating the Sirt3/TFEB Signaling Pathway to Attenuate Doxorubicin-Induced Cardiomyopathy.

Doxorubicin (DOX) chemotherapy in cancer patients increases the risk of the occurrence of cardiac dysfunction and even results in congestive heart failure. Despite the great progress of pathology in DOX-induced cardiomyopathy, the underlying molecular mechanisms remain elusive. Here, we investigate the protective effects and the underlying mechanisms of melatonin in DOX-induced cardiomyopathy. Our results clearly show that oral administration of melatonin prevented the deterioration of cardiac function caused by DOX treatment, which was evaluated by left ventricular ejection fraction and fractional shortening as well as cardiac fibrosis. The ejection fraction and fractional shortening in the DOX group were 49.48% and 25.5%, respectively, while melatonin treatment increased the ejection fraction and fractional shortening to 60.33 and 31.39 in wild-type mice. Cardiac fibrosis in the DOX group was 3.97%, while melatonin reduced cardiac fibrosis to 1.95% in wild-type mice. Sirt3 is a mitochondrial deacetylase and shows protective effects in diverse cardiovascular diseases. Therefore, to test whether Sirt3 is a key factor in protection, Sirt3 knockout mice were used, and it was found that the protective effects of melatonin in DOX-induced cardiomyopathy were partly abolished. Further analysis revealed that Sirt3 and its downstream molecule TFEB were downregulated in response to DOX treatment, while melatonin administration was able to significantly enhance the expressions of Sirt3 and TFEB. Our in vitro study demonstrated that melatonin enhanced lysosomal function by increasing the Sirt3-mediated increase at the TFEB level, and the accumulation of autolysosomes induced by DOX treatment was attenuated. Thus, autophagic flux disrupted by DOX treatment was restored by melatonin supplementation. In summary, our results demonstrate that melatonin protects the heart against DOX injury by the restoration of autophagic flux via the activation of the Sirt3/TFEB signaling pathway.