Ferulic acid attenuates brain microvascular endothelial cells damage caused by oxygen-glucose deprivation via punctate-mitochondria-dependent mitophagy

Unveiling the impact of aging on BBB and Alzheimer's disease: Factors and therapeutic implications

Alzheimer's disease (AD) is a highly prevalent neurodegenerative condition that has devastating effects on individuals, often resulting in dementia. AD is primarily defined by the presence of extracellular plaques containing insoluble β-amyloid peptide (Aβ) and neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein (P-tau). In addition, individuals afflicted by these age-related illnesses experience a diminished state of health, which places significant financial strain on their loved ones. Several risk factors play a significant role in the development of AD. These factors include genetics, diet, smoking, certain diseases (such as cerebrovascular diseases, obesity, hypertension, and dyslipidemia), age, and alcohol consumption. Age-related factors are key contributors to the development of vascular-based neurodegenerative diseases such as AD. In general, the process of aging can lead to changes in the immune system's responses and can also initiate inflammation in the brain. The chronic inflammation and the inflammatory mediators found in the brain play a crucial role in the dysfunction of the blood-brain barrier (BBB). Furthermore, maintaining BBB integrity is of utmost importance in preventing a wide range of neurological disorders. Therefore, in this review, we discussed the role of age and its related factors in the breakdown of the blood-brain barrier and the development of AD. We also discussed the importance of different compounds, such as those with anti-aging properties, and other compounds that can help maintain the integrity of the blood-brain barrier in the prevention of AD. This review builds a strong correlation between age-related factors, degradation of the BBB, and its impact on AD.

Role of pyroptosis in the pathogenesis of various neurological diseases

Pyroptosis, an inflammatory programmed cell death process, has recently garnered significant attention due to its pivotal role in various neurological diseases. This review delves into the intricate molecular signaling pathways governing pyroptosis, encompassing both caspase-1 dependent and caspase-1 independent routes, while emphasizing the critical role played by the inflammasome machinery in initiating cell death. Notably, we explore the Nucleotide-binding domain leucine-rich repeat (NLR) containing protein family, the Absent in melanoma 2-like receptor family, and the Pyrin receptor family as essential activators of pyroptosis. Additionally, we comprehensively examine the Gasdermin family, renowned for their role as executioner proteins in pyroptosis. Central to our review is the interplay between pyroptosis and various central nervous system (CNS) cell types, including astrocytes, microglia, neurons, and the blood-brain barrier (BBB). Pyroptosis emerges as a significant factor in the pathophysiology of each cell type, highlighting its far-reaching impact on neurological diseases. This review also thoroughly addresses the involvement of pyroptosis in specific neurological conditions, such as HIV infection, drug abuse-mediated pathologies, Alzheimer's disease, and Parkinson's disease. These discussions illuminate the intricate connections between pyroptosis, chronic inflammation, and cell death in the development of these disorders. We also conducted a comparative analysis, contrasting pyroptosis with other cell death mechanisms, thereby shedding light on their unique aspects. This approach helps clarify the distinct contributions of pyroptosis to neuroinflammatory processes. In conclusion, this review offers a comprehensive exploration of the role of pyroptosis in various neurological diseases, emphasizing its multifaceted molecular mechanisms within various CNS cell types. By elucidating the link between pyroptosis and chronic inflammation in the context of neurodegenerative disorders and infections, it provides valuable insights into potential therapeutic targets for mitigating these conditions.

Mitochondria in hypoxic pulmonary hypertension, roles and the potential targets

Mitochondria are the centrol hub for cellular energy metabolisms. They regulate fuel metabolism by oxygen levels, participate in physiological signaling pathways, and act as oxygen sensors. Once oxygen deprived, the fuel utilizations can be switched from mitochondrial oxidative phosphorylation to glycolysis for ATP production. Notably, mitochondria can also adapt to hypoxia by making various functional and phenotypes changes to meet the demanding of oxygen levels. Hypoxic pulmonary hypertension is a life-threatening disease, but its exact pathgenesis mechanism is still unclear and there is no effective treatment available until now. Ample of evidence indicated that mitochondria play key factor in the development of hypoxic pulmonary hypertension. By hypoxia-inducible factors, multiple cells sense and transmit hypoxia signals, which then control the expression of various metabolic genes. This activation of hypoxia-inducible factors considered associations with crosstalk between hypoxia and altered mitochondrial metabolism, which plays an important role in the development of hypoxic pulmonary hypertension. Here, we review the molecular mechanisms of how hypoxia affects mitochondrial function, including mitochondrial biosynthesis, reactive oxygen homeostasis, and mitochondrial dynamics, to explore the potential of improving mitochondrial function as a strategy for treating hypoxic pulmonary hypertension.

Targeting pyroptosis as a preventive and therapeutic approach for stroke

Stroke has caused tremendous social stress worldwide, yet despite decades of research and development of new stroke drugs, most have failed and rt-PA (Recombinant tissue plasminogen activator) is still the accepted treatment for ischemic stroke. the complexity of the stroke mechanism has led to unsatisfactory efficacy of most drugs in clinical trials, indicating that there are still many gaps in our understanding of stroke. Pyroptosis is a programmed cell death (PCD) with inflammatory properties and are thought to be closely associated with stroke. Pyroptosis is regulated by the GSDMD of the gasdermin family, which when cleaved by Caspase-1/Caspase-11 into N-GSDMD with pore-forming activity can bind to the plasma membrane to form small 10-20 nm pores, which would allow the release of inflammatory factors IL-18 and IL-1β before cell rupture, greatly exacerbating the inflammatory response. The pyroptosis occurs mainly in the border zone of cerebral infarction, and glial cells, neuronal cells and brain microvascular endothelial cells (BMECs) all undergo pyroptosis after stroke, which largely exacerbates the breakdown of the blood-brain barrier (BBB) and thus aggravates brain injury. Therefore, pyroptosis may be a good direction for the treatment of stroke. In this review, we focus on the latest mechanisms of action of pyroptosis and the process by which pyroptosis regulates stroke development. We also suggest potential therapeutic stroke drugs that target the pyroptosis pathway, providing additional therapeutic strategies for the clinical management of stroke. The role of pyroptosis after stroke. After stroke, microglia first rush to the damaged area and polarize into M1 and M2 types. Under the influence of various stimuli, microglia undergo pyroptosis, release pro-inflammatory factors, and are converted to the M1 type; astrocytes and neuronal cells also undergo pyroptosis under the stimulation of various pro-inflammatory factors, leading to astrocyte death due to increased osmotic pressure in the membrane, resulting in water absorption and swelling until rupture. BMECs, the main structural component of the BBB, also undergo pyroptosis when stimulated by pro-inflammatory factors released from microglia and astrocytes, leading to the destruction of the structural integrity of the BBB, ultimately causing more severe brain damage. In addition, GSDMD in neutrophils mainly mediate the release of NETs rather than pyroptosis, which also aggravates brain injury. IL-10=interleukin-10; TGF-β = transforming growth factor-β; IL-18=interleukin-18; IL-1β = interleukin-1β; TNF-α = tumor necrosis factor-α; iNOS=induced nitrogen monoxide synthase; MMPs=Matrix metalloproteinases; GSDMD = gasdermin D; BMECs=brain microvascular endothelial cells; BBB = blood-brain barrier.

Mitochondrial oxidative stress in brain microvascular endothelial cells: Triggering blood-brain barrier disruption

Blood-brain barrier disruption plays an important role in central nervous system diseases. This review provides information on the role of mitochondrial oxidative stress in brain microvascular endothelial cells in cellular dysfunction, the disruption of intercellular junctions, transporter dysfunction, abnormal angiogenesis, neurovascular decoupling, and the involvement and aggravation of vascular inflammation and illustrates related molecular mechanisms. In addition, recent drug and nondrug therapies targeting cerebral vascular endothelial cell mitochondria to repair the blood-brain barrier are discussed. This review shows that mitochondrial oxidative stress disorder in brain microvascular endothelial cells plays a key role in the occurrence and development of blood-brain barrier damage and may be critical in various pathological mechanisms of blood-brain barrier damage. These new findings suggest a potential new strategy for the treatment of central nervous system diseases through mitochondrial modulation of cerebral vascular endothelial cells.

Insights of Chinese herbal medicine for mitochondrial dysfunction in chronic cerebral hypoperfusion induced cognitive impairment: Existed evidences and potential directions

Chronic cerebral hypoperfusion (CCH) is one of the main pathophysiological markers of cognitive impairment in central nervous system diseases. Mitochondria are cores of energy generation and information process. Mitochondrial dysfunction is the key upstream factors of CCH induced neurovascular pathology. Increasing studies explored the molecular mechanisms of mitochondrial dysfunction and self-repair for effective targets to improve CCH-related cognitive impairment. The clinical efficacy of Chinese herbal medicine in the treatment of CCH induced cognitive impairment is definite. Existed evidences from pharmacological studies have further proved that, Chinese herbal medicine could improve mitochondrial dysfunction and neurovascular pathology after CCH by preventing calcium overload, reducing oxidative stress damage, enhancing antioxidant capacity, inhibiting mitochondria-related apoptosis pathway, promoting mitochondrial biogenesis and preventing excessive activation of mitophagy. Besides, CCH mediated mitochondrial dysfunction is one of the fundamental causes for neurodegeneration pathology aggravation. Chinese herbal medicine also has great potential therapeutic value in combating neurodegenerative diseases by targeting mitochondrial dysfunction.

Effects of Human Milk Oligosaccharides in Infant Health Based on Gut Microbiota Alteration

The primary active components of breast milk are human milk oligosaccharides (HMOs). HMOs provide many benefits to infants, including regulating their metabolism, immune system, and brain development. Recent studies have emphasized that HMOs act as prebiotics by the metabolism of intestinal microorganisms to produce short-chain fatty acids, which are crucial for infant development. In addition, HMOs with different structural characteristics can form different microbial compositions. HMOs-induced predominant microbes, including Bifidobacterium infantis, B. bifidum, B. breve, and B. longum, and their metabolites demonstrated pertinent health-promoting properties. Meanwhile, HMOs could also directly reduce the occurrence of diseases through the effects of preventing pathogen infection. In this review, we address the probable function of HMOs inside the HMOs-gut microbiota-infant network, by describing the physiological functions of HMOs and the implications of diet on the HMOs-gut microbiota-infant network.

Unraveling Pathophysiological Link Between Mitophagy Pathway and Vascular Dementia

Context: Vascular dementia (VaD) is the second most common type of dementia after Alzheimer’s disease worldwide. Vascular dementia is a neurodegenerative disorder characterized by gradual cognitive impairment. Ischemic and hemorrhagic strokes result in VaD, markedly distributing cerebral blood flow and decreasing patients’ cognitive and memory performance. Due to their high energy demands, neurons are more sensitive to cellular architecture changes and exposed to mitochondrial stress than other cell types. Mitochondrial dysfunction and selective autophagy of mitochondria, known as mitophagy, are associated with VaD. This review aims to elucidate the association between mitophagy and VaD. Evidence Acquisition: This review was conducted independently by at least two researchers dominant in various VaD studies. We searched databases including Elsevier, Google Scholar, and PubMed using the terms ‘vascular dementia’, ‘vascular cognitive impairment’, and ‘mitophagy’. We evaluated 70 articles on the relationship between VaD and mitophagy and interpreted the results. Adobe Photoshop 2022 was used for drawing figures by researchers. Results: The autophagy process plays a protective role in experimental VaD models via preserving vascular integrity and the structure of the blood-brain barrier, upregulating occludin and claudin protein expressions, reducing oxidative stress, and decreasing cognitive dysfunction. Some studies claim that autophagy could have adverse effects in a time-dependent manner against neuronal injury. Prolonged autophagy and overexpressed autophagic proteins induce ischemic injury and cause neuronal cells to undergo apoptotic cell death. Conclusions: Although there are limited studies on the activation of mitophagy-related pathways in VaD, and the definitive role of mitophagy in neuronal healing is unclear, further research is needed to elucidate mitophagy pathways in neurons.

Synthesis of mitochondria-targeted ferulic acid amide derivatives with antioxidant, anti-inflammatory activities and inducing mitophagy

The seventeen ferulic acid amide derivatives were synthesized by coupling mitochondrial carrier coumarin-3-carboxamide with acrylic acids. The results of cellular antioxidant activity and inhibitory effects on NO production against LPS-stimulated RAW264.7 macrophages indicated four compounds (8c, 8d, 9c, 9d) showed the higher dual-activities of antioxidant and anti-inflammatory. The structure-activity relationship was deduced. In regard to mechanism research, the most potent compound 8d which mainly distributed in mitochondria suppressed the secretion of inflammatory cytokines IL-6 and TNF-α, enhancing mitophagy to alleviate inflammatory response. Besides, the dual-activities were diminished by removal of coumarin carrier in 8d, suggesting the enrichment in mitochondria might be important for activities. This study showed that development of mitochondria-targeted antioxidants could be a feasible strategy to resist inflammation.

Polyphenols for the Treatment of Ischemic Stroke: New Applications and Insights

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Currently, the main therapeutic strategy involves the use of intravenous thrombolysis to restore cerebral blood flow to prevent the transition of the penumbra to the infarct core. However, due to various limitations and complications, including the narrow time window in which this approach is effective, less than 10% of patients benefit from such therapy. Thus, there is an urgent need for alternative therapeutic strategies, with neuroprotection against the ischemic cascade response after IS being one of the most promising options. In the past few decades, polyphenolic compounds have shown great potential in animal models of IS because of their high biocompatibility and ability to target multiple ischemic cascade signaling pathways, although low bioavailability is an issue that limits the applications of several polyphenols. Here, we review the pathophysiological changes following cerebral ischemia and summarize the research progress regarding the applications of polyphenolic compounds in the treatment of IS over the past 5 years. Furthermore, we discuss several potential strategies for improving the bioavailability of polyphenolic compounds as well as some essential issues that remain to be addressed for the translation of the related therapies to the clinic.

Ferulic acid exhibits anti-inflammatory effects by inducing autophagy and blocking NLRP3 inflammasome activation

Background

Inflammation is involved in the healing process; however, when inflammation is overactivated, multiple diseases can occur. The continued discovery of new anti-inflammatory drugs is crucial in the treatment of inflammation-linked diseases.

Objectives

Ferulic acid (FA), a precursor necessary for lignan synthesis, is widely distributed in plant-based whole foods and is a strong antioxidant. However, the effect of FA on the expression level of inflammatory factors in macrophages has not been fully clarified. The current study aimed to explore the anti-inflammatory effect and mechanism of ferulic acid.

Results

The results showed that THP-1 cells were induced to differentiate into macrophages by Phorbol-12-myristate-13-acetate (PMA), and THP-1-derived macrophages were stimulated by LPS to establish an inflammatory cell model. Compared with the control group, low (5 μmol·mL⁻¹), medium (10 μmol·mL⁻¹), and high (20 μmol·mL⁻¹) concentration ferulic acid groups have decreased cell viability and increased apoptosis rate in a dose-dependent manner. FA reduced the transcriptional levels of Interleukin-1β (IL-1β), Interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α). Importantly, FA-induced autophagy and inhibited NLRP3 inflammasome activation. 3-MA (a widely used autophagy inhibitor) enhanced the secretion of TNF-α, IL-6 and IL-1β. Moreover, autophagy inhibition by 3-MA resulted in increased proteins expression associated with NLRP3 inflammasome signaling pathway. Besides, the inhibition of inflammasome activation by MCC950 reduced the expression of TNF-α, IL-6 and IL-1β.

Conclusion

It is concluded that FA enhanced autophagy, inhibited the activation of NLRP3 inflammasome and reduced the expression and release of inflammatory factors.

Endothelial arginase 2 mediates retinal ischemia/reperfusion injury by inducing mitochondrial dysfunction

Objective

Retinal ischemic disease is a major cause of vision loss. Current treatment options are limited to late-stage diseases, and the molecular mechanisms of the initial insult are not fully understood. We have previously shown that the deletion of the mitochondrial arginase isoform, arginase 2 (A2), limits neurovascular injury in models of ischemic retinopathy. Here, we investigated the involvement of A2-mediated alterations in mitochondrial dynamics and function in the pathology.

Methods

We used wild-type (WT), global A2 knockout (A2KO-) mice, cell-specific A2 knockout mice subjected to retinal ischemia/reperfusion (I/R), and bovine retinal endothelial cells (BRECs) subjected to an oxygen-glucose deprivation/reperfusion (OGD/R) insult. We used western blotting to measure levels of cell stress and death markers and the mitochondrial fragmentation protein, dynamin related protein 1 (Drp1). We also used live cell mitochondrial labeling and Seahorse XF analysis to evaluate mitochondrial fragmentation and function, respectively.

Results

We found that the global deletion of A2 limited the I/R-induced disruption of retinal layers, fundus abnormalities, and albumin extravasation. The specific deletion of A2 in endothelial cells was protective against I/R-induced neurodegeneration. The OGD/R insult in BRECs increased A2 expression and induced cell stress and cell death, along with decreased mitochondrial respiration, increased Drp1 expression, and mitochondrial fragmentation. The overexpression of A2 in BREC also decreased mitochondrial respiration, promoted increases in the expression of Drp1, mitochondrial fragmentation, and cell stress and resulted in decreased cell survival. In contrast, the overexpression of the cytosolic isoform, arginase 1 (A1), did not affect these parameters.

Conclusions

This study is the first to show that A2 in endothelial cells mediates retinal ischemic injury through a mechanism involving alterations in mitochondrial dynamics and function.

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Ischemic retinopathy is a common feature of blinding eye disease.

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Arginase 2 overexpression in endothelial cells induces mitochondrial dysfunction.

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Endothelial-specific arginase 2 deletion improves neuronal survival after ischemia.

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Endothelial cell arginase 2 plays a crucial role in ischemic retinal injury.

Beyond Antioxidant Effects: Nature-Based Templates Unveil New Strategies for Neurodegenerative Diseases

The complex network of malfunctioning pathways occurring in the pathogenesis of neurodegenerative diseases (NDDs) represents a huge hurdle in the development of new effective drugs to be used in therapy. In this context, redox reactions act as crucial regulators in the maintenance of neuronal microenvironment homeostasis. Particularly, their imbalance results in the severe compromising of organism’s natural defense systems and subsequently, in the instauration of deleterious OS, that plays a fundamental role in the insurgence and progress of NDDs. Despite the huge efforts in drug discovery programs, the identification process of new therapeutic agents able to counteract the relentless progress of neurodegenerative processes has produced low or no effective therapies. Consequently, a paradigm-shift in the drug discovery approach for these diseases is gradually occurring, paving the way for innovative therapeutical approaches, such as polypharmacology. The aim of this review is to provide an overview of the main pharmacological features of most promising nature-based scaffolds for a possible application in drug discovery, especially for NDDs, highlighting their multifaceted effects against OS and neuronal disorders.

Ferulic acid alleviates lipotoxicity-induced hepatocellular death through the SIRT1-regulated autophagy pathway and independently of AMPK and Akt in AML-12 hepatocytes

Background

Lipotoxicity-induced cell death plays a detrimental role in the pathogenesis of metabolic diseases. Ferulic acid, widespread in plant-based food, is a radical scavenger with multiple bioactivities. However, the benefits of ferulic acid against hepatic lipotoxicity are largely unclear. Here, we investigated the protective effect of ferulic acid against palmitate-induced lipotoxicity and clarified its potential mechanisms in AML-12 hepatocytes.

Methods

AML-12 mouse hepatocytes were exposed to palmitate to mimic lipotoxicity. Different doses (25, 50, and 100 μM) of ferulic acid were added 2 h before palmitate treatment. Cell viability was detected by measuring lactate dehydrogenase release, nuclear staining, and the expression of cleaved-caspase-3. Intracellular reactive oxygen species content and mitochondrial membrane potential were analysed by fluorescent probes. The potential mechanisms were explored by molecular biological methods, including Western blotting and quantitative real-time PCR, and were further verified by siRNA interference.

Results

Our data showed that ferulic acid significantly inhibited palmitate-induced cell death, rescued mitochondrial membrane potential, reduced reactive oxygen species accumulation, and decreased inflammatory factor activation, including IL-6 and IL-1beta. Ferulic acid significantly stimulated autophagy in hepatocytes, whereas autophagy suppression blocked the protective effect of ferulic acid against lipotoxicity. Ferulic acid-activated autophagy, which was triggered by SIRT1 upregulation, was mechanistically involved in its anti-lipotoxicity effects. SIRT1 silencing blocked most beneficial changes induced by ferulic acid.

Conclusions

We demonstrated that the phytochemical ferulic acid, which is found in plant-based food, protected against hepatic lipotoxicity, through the SIRT1/autophagy pathway. Increased intake of ferulic acid-enriched food is a potential strategy to prevent and/or improve metabolic diseases with lipotoxicity as a typical pathological feature.

Biocompatibility of ferulic/succinic acid-grafted chitosan hydrogels for implantation after brain injury: A preliminary study

Nowadays it is known that neural cells are capable of regenerating after brain injury, but their success highly depends on the local environment, including the presence of a biological structure to support cell proliferation and restore the lost tissue. Different chitosan-based biomaterials have been employed in response to this necessity. We hypothesized that hydrogels made of antioxidant compounds functionalizing chitosan could provide a suitable environment to home new cells and offer a way to achieve brain repair. In this work, the implantation of functionalized chitosan biomaterials in a brain injury animal model was evaluated. The injury consisted of mechanical damage applied to the cerebral cortex of Wistar rats followed by the implantation of four different chitosan-based biomaterials. After 15 and 30 days, animals underwent magnetic resonance imaging, then they were sacrificed, and the brain tissue was analyzed by immunohistochemistry. The proliferation of microglia and astrocytes increased at the lesion zone, showing differences between the evaluated biomaterials. Also, cell nuclei were seen inside the biomaterials, indicating cell migration and biodegradation. Chitosan-based hydrogels are able to fill in the tissue cavity and bare cells for the endogenous restoration process. The addition of ferulic and succinic acid to the chitosan structure increases this capacity and decreases the inflammatory reaction to the implant.

Pharmacological targeting of MCL-1 promotes mitophagy and improves disease pathologies in an Alzheimer's disease mouse model

There is increasing evidence that inducing neuronal mitophagy can be used as a therapeutic intervention for Alzheimer's disease. Here, we screen a library of 2024 FDA-approved drugs or drug candidates, revealing UMI-77 as an unexpected mitophagy activator. UMI-77 is an established BH3-mimetic for MCL-1 and was developed to induce apoptosis in cancer cells. We found that at sub-lethal doses, UMI-77 potently induces mitophagy, independent of apoptosis. Our mechanistic studies discovered that MCL-1 is a mitophagy receptor and directly binds to LC3A. Finally, we found that UMI-77 can induce mitophagy in vivo and that it effectively reverses molecular and behavioral phenotypes in the APP/PS1 mouse model of Alzheimer's disease. Our findings shed light on the mechanisms of mitophagy, reveal that MCL-1 is a mitophagy receptor that can be targeted to induce mitophagy, and identify MCL-1 as a drug target for therapeutic intervention in Alzheimer's disease.

Ferulic acid delayed amyloid β-induced pathological symptoms by autophagy pathway via a fasting-like effect in Caenorhabditis elegans

The amyloid β (Aβ) generation or aggregation plays a crucial role in Alzheimer's disease (AD). Autophagy agonists, which function as the clearance of Aβ, could be the potential drug candidates against AD. In staple food crops, ferulic acid (FA) is an enormously copious and almost ubiquitous phenolic antioxidant. In the present study, FA significantly inhibited Aβ-induced pathological symptoms of paralysis and hypersensitivity to exogenous serotonin, meanwhile restrained Aβ monomers, oligomers, and deposits in AD C. elegans. FA increased the expression of autophagy reporter LGG-1 and enhanced autophagy flux. However, the autophagy inhibitors abolished the restrictive action of FA on the worm paralysis phenotype. According to these results, FA triggered autophagy and ameliorated Aβ-induced pathological symptoms by the autophagy pathway. Moreover, FA activated the HLH-30 transcription factor to nuclear localization, which acts upstream of autophagy in fasted animals, reduced the level of lipids, but affected nor the growth of E. coli OP50, neither animal food intake behavior. These suggest that FA induced a fasting-like effect to activate the autophagy pathway. Additionally, FA ameliorated poly Q aggregations in Huntington's disease worm. Thus, FA could not only affect AD, broadly but also neurodegenerative diseases characterized by misfolded or aggregated proteins.

Hypoxic Regulation of Mitochondrial Metabolism and Mitophagy in Nucleus Pulposus Cells Is Dependent on HIF-1α-BNIP3 Axis

Nucleus pulposus (NP) cells reside in an avascular and hypoxic microenvironment of the intervertebral disc and are predominantly glycolytic due to robust HIF-1 activity. It is generally thought that NP cells contain few functional mitochondria compared with cells that rely on oxidative metabolism. Consequently, the contribution of mitochondria to NP cell metabolism and the role of hypoxia and HIF-1 in mitochondrial homeostasis is poorly understood. Using mitoQC reporter mice, we show for the first time to our knowledge that NP cell mitochondria undergo age-dependent mitophagy in vivo. Mechanistically, in vitro studies suggest that, under hypoxic conditions, mitochondria in primary NP cells undergo HIF-1α-dependent fragmentation, controlled by modulating the levels of key proteins DRP1 and OPA1 that are involved in mitochondrial fission and fusion, respectively. Seahorse assays and steady state metabolic profiling coupled with [1-2-¹³ C]-glucose flux analysis revealed that in hypoxia, HIF-1α regulated metabolic flux through coordinating glycolysis and the mitochondrial TCA cycle interactions, thereby controlling the overall biosynthetic capacity of NP cells. We further show that hypoxia and HIF-1α trigger mitophagy in NP cells through the mitochondrial translocation of BNIP3, an inducer of receptor-mediated mitophagy. Surprisingly, however, loss of HIF-1α in vitro and analysis of NP-specific HIF-1α null mice do not show a decrease in mitophagic flux in NP cells but a compensatory increase in NIX and PINK1-Parkin pathways with higher mitochondrial number. Taken together, our studies provide novel mechanistic insights into the complex interplay between hypoxia and HIF-1α signaling on the mitochondrial metabolism and quality control in NP cells. © 2020 American Society for Bone and Mineral Research.

Ferulic acid protects cardiomyocytes from TNF-α/cycloheximide-induced apoptosis by regulating autophagy

Acute myocardial infarction (AMI) results in irreversible cardiac cell damage or death because of decreased blood flow to the heart. Apoptosis plays an important role in the process of tissue damage after myocardial infarction (MI), which has pathological and therapeutic implications. Ferulic acid (FA) is a phenolic acid endowed with strong antioxidative and cytoprotective activities. The present study aimed to investigate whether FA protects cardiomyocytes from apoptosis by regulating autophagy, which is a cellular self-digestion process, and one of the first lines of defense against oxidative stress. Apoptosis was induced by TNF-α (10 ng/mL) and cycloheximide (CHX, 5 μg/mL) in rat H9c2 cardiomyocytes. FA-inhibited TNF-α/CHX-induced apoptosis was determined by the quantification of TUNEL-positive cells, and the effect was associated with decreased ROS production and inhibited caspase3 activation. FA treatment enhanced autophagy and increased autophagy-associated protein expression, leading to an inhibition of mTOR signaling. When co-treated with 3-methyladenine (3-MA), an autophagy inhibitor, the anti-apoptotic effect of FA was attenuated. In an in vivo mouse MI model, FA treatment decreased the apoptotic cell number, reduced infarct size, and improved cardiac performance, as determined by histological and echocardiographic assessments. Taken collectively, these results suggest that FA could protect cardiomyocytes from apoptosis by enhancing autophagy.

Protective role of three differently processed corn bran on glucose and lipid concentrations in d-galactose-induced mice model

In this research, the effects of three differently processed corn bran (corn bran soluble hemicellulose (HEM), hemicellulose hydrolyzed by oxalic acid (HOA), Amberlite XAD-2 eluate (XE)) on the changes of glucose and lipid concentrations of d-galactose (d-gal)-induced mice were investigated. The mice were divided into five groups and intragastric administration HEM, HOA, and XE at 200 mg/kg Body Weight (BW) for continuously 6 weeks. Mice were submitted under oral glucose tolerance test (OGTT).Then, the serum insulin, glucagon-like peptide-1(GLP-1), serum C-peptide, hepatic glycogen (HG), muscle glycogen (MG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) of all the mice were detected. As we can see, by inducing with d-gal, the glucose and lipid concentrations of aging mice could be effectively regulated by HEM, HOA, and XE. High degree of esterification feruloylated oligosaccharides has the most obvious effect of regulating glucose and lipid concentrations. PRACTICAL APPLICATIONS: Corn bran has not been fully paid attention owing to the rough taste and the poor water solubility. Actually, corn bran, a renewable resource available in a large quantity, could be a goods source of valuable consumer products. The results of this study indicated that three differently processed corn brans could regulate glucose and lipid concentrations and XE had the most obvious effect of regulating glucose and lipid concentrations. Corn bran could advantage as a new type of environmentally and inexpensive food supplements on reducing blood glucose and lipid concentrations.

Reasonably activating Nrf2: A long-term, effective and controllable strategy for neurodegenerative diseases

Neurodegenerative diseases are a variety of debilitating and fatal disorder in central nervous system (CNS). Besides targeting neuronal activity by influencing neurotransmitters or their corresponding receptors, modulating the underlying processes that lead to cell death, such as oxidative stress and mitochondrial dysfunction, should also be emphasized as an assistant strategy for neurodegeneration therapy. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) has been closely verified to be related to anti-inflammation and oxidative stress, rationally regulating its belonging pathway and activating Nrf2 is emphasized to be a potential treatment approach. There have existed multiple Nrf2 activators with different mechanisms and diverse structures, but those applied for neuro-disorders are still limited. On the basis of research arrangement and compound summary, we put forward the limitations of existing Nrf2 activators for neurodegenerative diseases and their future developing directions in enhancing the blood-brain barrier permeability to make Nrf2 activators function in CNS and designing Nrf2-based multi-target-directed ligands to affect multiple nodes in pathology of neurodegenerative diseases.

The impact of endothelial cell death in the brain and its role after stroke: A systematic review

The supply of oxygen and nutrients to the brain is vital for its function and requires a complex vascular network that, when disturbed, results in profound neurological dysfunction. As part of the pathology in stroke, endothelial cells die. As endothelial cell death affects the surrounding cellular environment and is a potential target for the treatment and prevention of neurological disorders, we have systematically reviewed important aspects of endothelial cell death with a particular focus on stroke. After screening 2876 publications published between January 1, 2010 and August 7, 2019, we identified 154 records to be included. We found that endothelial cell death occurs rapidly as well as later after the onset of stroke conditions. Among the different cell death mechanisms, apoptosis was the most widely investigated (92 records), followed by autophagy (20 records), while other, more recently defined mechanisms received less attention, such as lysosome-dependent cell death (2 records) and necroptosis (2 records). We also discuss the differential vulnerability of brain cells to injury after stroke and the role of endothelial cell death in the no-reflow phenomenon with a special focus on the microvasculature. Further investigation of the different cell death mechanisms using novel tools and biomarkers will greatly enhance our understanding of endothelial cell death. For this task, at least two markers/criteria are desirable to determine cell death subroutines according to the recommendations of the Nomenclature Committee on Cell Death.

Berberine Alleviates Tau Hyperphosphorylation and Axonopathy-Associated with Diabetic Encephalopathy via Restoring PI3K/Akt/GSK3β Pathway

BACKGROUND

Axonopathy is closely linked to the development of diabetic encephalopathy induced by type II diabetes (T2D). Berberine has been shown to cross the blood-brain barrier and holds promising effect for neuronal damage in diabetes.

OBJECTIVE

The present study investigated the protective effect and the underlying mechanism of berberine on neuronal axonopathy in both in vitro and in vivo models.

METHODS

High glucose/high fat diet and streptozotocin injection-induced T2D rat model was used. Berberine was administered p.o. to T2D rat model for 10 weeks. Morris water maze test, in vivo neuronal tracing, immunohistochemistry, and western blot analysis were performed to evaluate the protective effects of berberine in T2D-induced diabetic encephalopathy rats. Primary cultured neurons were used to further explore the underlying mechanisms in vitro.

RESULTS

Berberine dramatically reduced blood glucose and serum insulin levels and alleviated insulin resistance. Berberine significantly attenuated memory impairment, axonopathy, and tau hyperphosphorylation, and also restored PI3K/Akt/GSK3β signaling pathway in T2D rats. In vitro, berberine induced an increase in the phosphorylation of PI3K/Akt as well as GSK3β in high glucose-treated primary neurons. Furthermore, berberine-induced PI3K/Akt activation also resulted in the dephosphorylation of tau protein, which could improve axonal transport impairment in high glucose-treated primary neurons. Pretreated neurons with LY294002, an inhibitor of PI3K, partially blocked berberine-inhibited tau phosphorylation and berberine-activated PI3K/Akt signaling pathway.

CONCLUSIONS

Berberine exerts the protective effect against cognitive deficits by improving tau hyperphosphorylation and the axonal damage through restoring PI3K/Akt/GSK3β signaling pathway.

Increased mitochondrial fission is critical for hypoxia-induced pancreatic beta cell death

Hypoxia-mediated pancreatic beta cell death is one of the main causes of pancreatic beta celldeath, which leads to the loss of functional pancreatic beta cell mass and type 1 diabetes andtype 2 diabetes.However, the molecular mechanisms that control life and death of pancreatic beta cells remain poorly understood. Here we showed that mitochondrial fission was strongly induced in pancreatic beta cellsmainly due to an elevation of DRP1^S616 phosphorylation through HIF-1αactivation and subsequent DRP1 mitochondrial translocation. Hypoxia-induced pancreatic beta cell death can be reversed by the inhibition of mitochondrial fission viaDRP1 knockdown. We further demonstrated that hypoxia-induced mitochondrial fission untightened the cristae formation, which subsequently triggers mitochondrial cytochrome c release and consequent caspase activation. Moreover, treatment with mitochondrial division inhibitor-1 (Mdivi-1), a specific inhibitor of DRP1-mediated mitochondrial fission, significantly suppressedbeta cell death in vitro, indicating a promising therapeutic strategy for treatment of diabetes.Taken together, our results reveal a crucial role for the DRP1-mediated mitochondrial fission in hypoxia-induced beta cell death, which provides a strong evidence for thisprocess as drug target indiabetestreatment.

Hydroxysafflor yellow a protects brain microvascular endothelial cells against oxygen glucose deprivation/reoxygenation injury: Involvement of inhibiting autophagy via class I PI3K/Akt/mTOR signaling pathway

The present study aimed to test whether Hydroxysafflor yellow A (HSYA) protects the brain microvascular endothelial cells (BMECs) injury induced by oxygen glucose deprivation/reoxygenation (OGD/R) via the PI3K/Akt/mTOR autophagy signaling pathway. Primary rat BMECs were cultured and identified by the expression of factor VIII-related antigen before being exposed to OGD/R to imitate ischemia/reperfusion (I/R) damage in vitro. The protective effect of HSYA was evaluated by assessing (1) cellular morphologic and ultrastructural changes; (2) cell viability and cytotoxicity; (3) transendothelial electrical resistance (TEER) of monolayer BMECs; (4) cell apoptosis; (5) fluorescence intensity of LC3B; (6) LC3 mRNA expression; (7) protein expressions of LC3, Beclin-1, Zonula occludens-1 (ZO-1), phospho-Akt (p-Akt), Akt, phospho-mTOR (p-mTOR) and mTOR. It was found that HSYA (20, 40, and 80 μM) and 3-MA effectively reversed the cellular morphological and ultrastructural changes, increased cell survival, normalized the permeability of BMECs, and suppressed apoptosis induced by OGD/R (2 h OGD followed by 24 h reoxygenation). Concurrently, HSYA and 3-MA also inhibited OGD/R-induced autophagy evidenced by the decreased number of autophagosomes and down-regulated levels of LC3 and Beclin-1 proteins and mRNAs. HSYA (80 μM), in combination with 3-MA showed a synergistic effect. Mechanistic studies revealed that HSYA (80 μM) markedly increased the levels of p-Akt and p-mTOR proteins. Blockade of PI3K activity by ZSTK474 abolished its anti-autophagic and pro-survival effect and lowered both Akt and mTOR phosphorylation levels. Taken together, these results suggest that HSYA protects BMECs against OGD/R-induced injury by inhibiting autophagy via the Class I PI3K/Akt/mTOR signaling pathway.