PACS2 is required for ox-LDL-induced endothelial cell apoptosis by regulating mitochondria-associated ER membrane formation and mitochondrial Ca2+ elevation

The correlation between mitochondria-associated endoplasmic reticulum membranes (MAMs) and Ca2+ transport in the pathogenesis of diseases

Mitochondria and the endoplasmic reticulum (ER) are vital organelles that influence various cellular physiological and pathological processes. Recent evidence shows that about 5%-20% of the mitochondrial outer membrane is capable of forming a highly dynamic physical connection with the ER, maintained at a distance of 10-30 nm. These interconnections, known as MAMs, represent a relatively conserved structure in eukaryotic cells, acting as a critical platform for material exchange between mitochondria and the ER to maintain various aspects of cellular homeostasis. Particularly, ER-mediated Ca2+ release and recycling are intricately associated with the structure and functionality of MAMs. Thus, MAMs are integral in intracellular Ca2+ transport and the maintenance of Ca2+ homeostasis, playing an essential role in various cellular activities including metabolic regulation, signal transduction, autophagy, and apoptosis. The disruption of MAMs observed in certain pathologies such as cardiovascular and neurodegenerative diseases as well as cancers leads to a disturbance in Ca2+ homeostasis. This imbalance potentially aggravates pathological alterations and disease progression. Consequently, a thorough understanding of the link between MAM-mediated Ca2+ transport and these diseases could unveil new perspectives and therapeutic strategies. This review focuses on the changes in MAMs function during disease progression and their implications in relation to MAM-associated Ca2+ transport.

Understanding PACS2 syndrome's pathomechanism by studying E209K and E211K mutations

Phosphofurin acidic cluster sorting protein 2 (PACS2) plays a vital role in maintaining cellular homeostasis by regulating protein trafficking between cellular membranes. This function impacts crucial processes like apoptosis, mitochondria-endoplasmic reticulum interaction, and subsequently Ca2+ flux, lipid biosynthesis, and autophagy. Missense mutations, particularly E209K and E211K, are linked to developmental and epileptic encephalopathy-66 (DEE66), known as PACS2 syndrome. Individuals with this syndrome exhibit neurodevelopmental delay, seizures, facial dysmorphism, hypotonia, and delayed motor skills.Understanding the impact of these missense mutations on molecular processes is crucial. Studies suggest that E209K mutation decreases phosphorylation, increases the survival time of protein, and modifies protein-protein interaction, consequently leading to disruption of calcium flux and lower resistance to apoptosis induction. Unfortunately, to date, only a limited number of research groups have investigated the effects of mutations in the PACS2 gene. Current research on PACS2 syndrome is hampered by the lack of suitable models. While in vitro models using transfected cell lines offer insights, they cannot fully capture the disease's complexity.To address this, utilizing cells from individuals with PACS2 syndrome, specifically induced pluripotent stem cells (iPSCs), holds promise for understanding phenotypic diversity and developing personalized therapies. However, iPSC models may not fully capture tissue-specific effects of the E209K/E211K mutation. In vivo studies using animal models, particularly mice, could overcome these limitations.This review summarizes current knowledge about PACS2 structure and functions, explores the cellular consequences of E209K and E211K mutations, and highlights the potential of iPSC and mouse models in advancing our understanding of PACS2 syndrome.

A new perspective on liver diseases: Focusing on the mitochondria-associated endoplasmic reticulum membranes

The pathogenesis of liver diseases is multifaceted and intricate, posing a persistent global public health challenge with limited therapeutic options. Therefore, further research into liver diseases is imperative for better comprehension and advancement in treatment strategies. Numerous studies have confirmed the endoplasmic reticulum (ER) and mitochondria as key organelles driving liver diseases. Notably, the mitochondrial-associated ER membranes (MAMs) establish a physical and functional connection between the ER and mitochondria, highlighting the importance of inter-organelle communication in maintaining their functional homeostasis. This review delves into the intricate architecture and regulative mechanism of the integrated MAM that facilitate the physiological transfer of signals and substances between organelles. Additionally, we also provide a detailed overview regarding the varied pathogenic roles of malfunctioning MAM in liver diseases, focusing on its involvement in the progression of ER stress and mitochondrial dysfunction, the regulation of mitochondrial dynamics and Ca2+ transfer, as well as the disruption of lipid and glucose homeostasis. Furthermore, the current challenges and prospects associated with MAM in liver disease research are thoroughly discussed. In conclusion, elucidating the specific structure and function of MAM in different liver diseases may pave the way for novel therapeutic strategies.

Mzb1 Attenuates Atherosclerotic Plaque Vulnerability in ApoE-/- Mice by Alleviating Apoptosis and Modulating Mitochondrial Function

In this study, we investigated the protective role of Mzb1 in atherosclerotic plaque vulnerability. To explore the impact of Mzb1, we analyzed Mzb1 expression, assessed apoptosis, and evaluated mitochondrial function in atherosclerosis (AS) mouse models and human vascular smooth muscle cells (HVSMCs). We observed a significant decrease in Mzb1 expression in AS mouse models and ox-LDL-treated HVSMCs. Downregulation of Mzb1 increased ox-LDL-induced apoptosis and cholesterol levels of HVSMCs, while Mzb1 overexpression alleviated these effect. Mzb1 was found to enhance mitochondrial function, as evidenced by restored ATP synthesis, mitochondrial membrane potential, and reduced mtROS production. Moreover, Mzb1 overexpression attenuated atherosclerotic plaque vulnerability in ApoE-/- mice. Our findings suggest that Mzb1 overexpression regulates the AMPK/SIRT1 signaling pathway, leading to the attenuation of atherosclerotic plaque vulnerability. This study provides compelling evidence for the protective effect of Mzb1 on atherosclerotic plaques by alleviating apoptosis and modulating mitochondrial function in ApoE-/- mice.

Calcium signaling crosstalk between the endoplasmic reticulum and mitochondria, a new drug development strategies of kidney diseases

Calcium (Ca2+) acts as a second messenger and constitutes a complex and large information exchange system between the endoplasmic reticulum (ER) and mitochondria; this process is involved in various life activities, such as energy metabolism, cell proliferation and apoptosis. Increasing evidence has suggested that alterations in Ca2+ crosstalk between the ER and mitochondria, including alterations in ER and mitochondrial Ca2+ channels and related Ca2+ regulatory proteins, such as sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), inositol 1,4,5-trisphosphate receptor (IP3R), and calnexin (CNX), are closely associated with the development of kidney disease. Therapies targeting intracellular Ca2+ signaling have emerged as an emerging field in the treatment of renal diseases. In this review, we focused on recent advances in Ca2+ signaling, ER and mitochondrial Ca2+ monitoring methods and Ca2+ homeostasis in the development of renal diseases and sought to identify new targets and insights for the treatment of renal diseases by targeting Ca2+ channels or related Ca2+ regulatory proteins.

Dialogue between mitochondria and endoplasmic reticulum-potential therapeutic targets for age-related cardiovascular diseases

Mitochondria-associated endoplasmic reticulum membranes (MAMs) act as physical membrane contact sites facilitating material exchange and signal transmission between mitochondria and endoplasmic reticulum (ER), thereby regulating processes such as Ca2+/lipid transport, mitochondrial dynamics, autophagy, ER stress, inflammation, and apoptosis, among other pathological mechanisms. Emerging evidence underscores the pivotal role of MAMs in cardiovascular diseases (CVDs), particularly in aging-related pathologies. Aging significantly influences the structure and function of the heart and the arterial system, possibly due to the accumulation of reactive oxygen species (ROS) resulting from reduced antioxidant capacity and the age-related decline in organelle function, including mitochondria. Therefore, this paper begins by describing the composition, structure, and function of MAMs, followed by an exploration of the degenerative changes in MAMs and the cardiovascular system during aging. Subsequently, it discusses the regulatory pathways and approaches targeting MAMs in aging-related CVDs, to provide novel treatment strategies for managing CVDs in aging populations.

Noncoding RNAs in atherosclerosis: regulation and therapeutic potential

Atherosclerosis, a chronic disease of arteries, results in high mortality worldwide as the leading cause of cardiovascular disease. The development of clinically relevant atherosclerosis involves the dysfunction of endothelial cells and vascular smooth muscle cells. A large amount of evidence indicates that noncoding RNAs, such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), are involved in various physiological and pathological processes. Recently, noncoding RNAs were identified as key regulators in the development of atherosclerosis, including the dysfunction of endothelial cells, and vascular smooth muscle cells and it is pertinent to understand the potential function of noncoding RNAs in atherosclerosis development. In this review, the latest available research relates to the regulatory role of noncoding RNAs in the progression of atherosclerosis and the therapeutic potential for atherosclerosis is summarized. This review aims to provide a comprehensive overview of the regulatory and interventional roles of ncRNAs in atherosclerosis and to inspire new insights for the prevention and treatment of this disease.

Mitochondria-associated endoplasmic reticulum membrane as a mediator of vanadium-induced endoplasmic reticulum quality control in duck brains

Vanadium (V) plays a crucial role in normal cells, but excess V causes multi-organ toxicity, including neurotoxicity. Mitochondria-associated endoplasmic reticulum membrane (MAM) is a dynamic structure between endoplasmic reticulum (ER) and mitochondria that mediates ER quality control (ERQC). To explore the effects of excess V on MAM and ERQC in the brain, 72 ducks were randomly divided into two groups: the control group (basal diet) and the V group (30 mg V/kg basal diet). On days 22 and 44, brain tissues were collected for histomorphological observation and determination of trace element contents. In addition, the mRNA and protein levels of MAM and ERQC-related factors in the brain were analyzed. Results show that excessive V causes the imbalance of trace elements, the integrity disruption of MAM, rupture of ER and autophagosomes formation. Moreover, it inhibits IP3R and VDAC1 co-localization, down-regulates the expression levels of MAM-related factors, but up-regulates the expression levels of ERQC and autophagy related factors. Together, results indicate that V exposure causes disruption of MAM and activates ERQC, which is further causing autophagy.

Target and Cell Therapy for Atherosclerosis and CVD

Cardiovascular diseases (CVD) and, in particular, atherosclerosis, remain the main cause of death in the world today. Unfortunately, in most cases, CVD therapy begins after the onset of clinical symptoms and is aimed at eliminating them. In this regard, early pathogenetic therapy for CVD remains an urgent problem in modern science and healthcare. Cell therapy, aimed at eliminating tissue damage underlying the pathogenesis of some pathologies, including CVD, by replacing it with various cells, is of the greatest interest. Currently, cell therapy is the most actively developed and potentially the most effective treatment strategy for CVD associated with atherosclerosis. However, this type of therapy has some limitations. In this review, we have tried to summarize the main targets of cell therapy for CVD and atherosclerosis in particular based on the analysis using the PubMed and Scopus databases up to May 2023.

Zearalenone induces mitochondria-associated endoplasmic reticulum membranes dysfunction in piglet Sertoli cells based on endoplasmic reticulum stress

Zearalenone (ZEA) is an estrogen-like mycotoxin, which mainly led to reproductive toxicity. The study aimed to investigate the molecular mechanism of ZEA-induced dysfunction of mitochondria-associated endoplasmic reticulum membranes (MAM) in piglet Sertoli cells (SCs) via the endoplasmic reticulum stress (ERS) pathway. In this study, SCs were used as a research object that was exposed to ZEA, and ERS inhibitor 4-Phenylbutyrate acid (4-PBA) was used as a reference. The results showed that ZEA damaged cell viability and increased Ca²⁺ levels; damaged the structure of MAM; up-regulated the relative mRNA and protein expression of glucose-regulated protein 75 (Grp75) and mitochondrial Rho-GTPase 1 (Miro1), while inositol 1,4,5-trisphosphate receptor (IP3R), voltage-dependent anion channel 1 (VDAC1), mitofusin2 (Mfn2) and phosphofurin acidic cluster protein 2 (PACS2) were down-regulated. After a 3 h 4-PBA-pretreatment, ZEA was added for mixed culture. The results of 4-PBA pretreatment showed that inhibition of ERS reduced the cytotoxicity of ZEA against piglet SCs. Compared with the ZEA group, inhibition of ERS increased cell viability and decreased Ca²⁺ levels; restored the structural damage of MAM; down-regulated the relative mRNA and protein expression of Grp75 and Miro1; and up-regulated the relative mRNA and protein expression of IP3R, VDAC1, Mfn2, and PACS2. In conclusion, ZEA can induce MAM dysfunction in piglet SCs via the ERS pathway, whereas ER can regulate mitochondria through MAM.

Inhibition of Mitochondrial Fission Alleviates Zearalenone-Induced Mitochondria-Associated Endoplasmic Reticulum Membrane Dysfunction in Piglet Sertoli Cells

This study aimed to investigate the effects of zearalenone (ZEA) on piglet Sertoli cell (SC)-mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs) based on mitochondrial fission, and to explore the molecular mechanism of ZEA-induced cell damage. After the SCs were exposed to the ZEA, the cell viability decreased, the Ca2+ levels increased, and the MAM showed structural damage. Moreover, glucose-regulated protein 75 (Grp75) and mitochondrial Rho-GTPase 1 (Miro1) were upregulated at the mRNA and protein levels. However, phosphofurin acidic cluster protein 2 (PACS2), mitofusin2 (Mfn2), voltage-dependent anion channel 1 (VDAC1), and inositol 1,4,5-trisphosphate receptor (IP3R) were downregulated at the mRNA and protein levels. A pretreatment with mitochondrial division inhibitor 1 (Mdivi-1) decreased the ZEA-induced cytotoxicity toward the SCs. In the ZEA + Mdivi-1 group, the cell viability increased, the Ca2+ levels decreased, the MAM damage was repaired, and the expression levels of Grp75 and Miro1 decreased, while those of PACS2, Mfn2, VDAC1, and IP3R increased compared with those in the ZEA-only group. Thus, ZEA causes MAM dysfunction in piglet SCs through mitochondrial fission, and mitochondria can regulate the ER via MAM.

Using mass spectrometry imaging to visualize age-related subcellular disruption

Metabolic homeostasis balances the production and consumption of energetic molecules to maintain active, healthy cells. Cellular stress, which disrupts metabolism and leads to the loss of cellular homeostasis, is important in age-related diseases. We focus here on the role of organelle dysfunction in age-related diseases, including the roles of energy deficiencies, mitochondrial dysfunction, endoplasmic reticulum (ER) stress, changes in metabolic flux in aging (e.g., Ca2+ and nicotinamide adenine dinucleotide), and alterations in the endoplasmic reticulum-mitochondria contact sites that regulate the trafficking of metabolites. Tools for single-cell resolution of metabolite pools and metabolic flux in animal models of aging and age-related diseases are urgently needed. High-resolution mass spectrometry imaging (MSI) provides a revolutionary approach for capturing the metabolic states of individual cells and cellular interactions without the dissociation of tissues. mass spectrometry imaging can be a powerful tool to elucidate the role of stress-induced cellular dysfunction in aging.

Mitochondria-associated endoplasmic reticulum membranes: A promising toxicity regulation target

Mitochondria-associated endoplasmic reticulum membranes (MAMs) are dynamic suborganelle membranes that physically couple endoplasmic reticulum (ER) and mitochondria to provide a platform for exchange of intracellular molecules and crosstalk between the two organelles. Dysfunctions of mitochondria and ER and imbalance of intracellular homeostasis have been discovered in the research of toxics. Cellular activities such as oxidative stress, ER stress, Ca²⁺ transport, autophagy, mitochondrial fusion and fission, and apoptosis mediated by MAMs are closely related to the toxicological effects of various toxicants. These cellular activities mediated by MAMs crosstalk with each other. Regulating the structure and function of MAMs can alleviate the damage caused by toxicants to some extent. In this review, we discuss the relationships between MAMs and the mechanisms of toxicological effects, and highlight MAMs as a potential target for protection against toxicants.

Relationship between Brain Metabolic Disorders and Cognitive Impairment: LDL Receptor Defect

The low-density-lipoprotein receptor (LDLr) removes low-density lipoprotein (LDL), an endovascular transporter that carries cholesterol from the bloodstream to peripheral tissues. The maintenance of cholesterol content in the brain, which is important to protect brain function, is affected by LDLr. LDLr co-localizes with the insulin receptor and complements the internalization of LDL. In LDLr deficiency, LDL blood levels and insulin resistance increase, leading to abnormal cholesterol control and cognitive deficits in atherosclerosis. Defects in brain cholesterol metabolism lead to neuroinflammation and blood–brain-barrier (BBB) degradation. Moreover, interactions between endoplasmic reticulum stress (ER stress) and mitochondria are induced by ox-LDL accumulation, apolipoprotein E (ApoE) regulates the levels of amyloid beta (Aβ) in the brain, and hypoxia is induced by apoptosis induced by the LDLr defect. This review summarizes the association between neurodegenerative brain disease and typical cognitive deficits.

Induction of apoptosis in SGC-7901 cells by iridium(III) complexes via endoplasmic reticulum stress-mitochondrial dysfunction pathway

This study was intended to evaluate the anticancer activity of three newly synthesized iridium(III) complexes [Ir(ppy)₂(PEIP)](PF₆) (1) (ppy = 2-phenylpyridine, PEIP = 2-phenethyl-1H-imidazo[4,5-f][1,10]phenanthroline), [Ir(ppy)₂(SIP)](PF₆) (2) (SIP = (E)-2-styryl-1H-imidazo[4,5-f][1,10]phenanthroline) and [Ir(ppy)₂(PEYIP)](PF₆) (3) (PEYIP = 2-phenethynyl-1H-imidazo[4,5-f][1,10]phenanthroline). The cytotoxic activity in vitro against A549, SGC-7901, HepG2, HeLa and normal NIH3T3 cells was investigated by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. We found that the complexes 1, 2 and 3 significantly inhibited cell proliferation, in particular, complexes 2 and 3 show high cytotoxic effect on SGC-7901 cells with an IC₅₀ value of 5.8 ± 0.7 and 4.4 ± 0.1 μM. Moreover, cell cycle assay revealed that the complexes could block G2/M phase of the cell cycle. Apoptotic evaluation by Annexin V/PI staining indicated that complexes 1-3 can induce apoptosis in SGC-7901 cells. In addition, microscopy detection suggested that disruption of mitochondrial functions, characterized by increased generation of intracellular ROS and Ca²⁺ as well as decrease of mitochondrial membrane potential. Western blot analysis shows that the complexes upregulate the expression of pro-apoptotic Bax and downregulate the expression of anti-apoptotic Bcl-2, which further activates caspase-3 and prompts the cleavage of PARP. Taken together, these results demonstrated that complexes 1-3 exert a potent anticancer effect on SGC-7901 cells via ROS-mediated endoplasmic reticulum stress-mitochondrial apoptotic pathway and have a potential to be developed as novel chemotherapeutic agents for human gastric cancer. Three new iridium(III) complexes [Ir(ppy)₂(PEIP)](PF₆) (1) (ppy = 2-phenylpyridine, PEIP = 2-phenethyl-1H-imidazo[4,5-f][1,10]phenanthroline), [Ir(ppy)₂(SIP)](PF₆) (2) (SIP = 2-styryl-1H-imidazo[4,5-f][1,10]phenanthroline) and [Ir(ppy)₂(PEYIP)](PF₆) (3) (PEYIP = 2-phenethynyl-1H-imidazo[4,5-f][1,10]phenanthroline) were synthesized and characterized. The anticancer activity in vitro was investigated by 3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) method. The results show that the complexes induce apoptosis via ROS-mediated endoplasmic reticulum stress-mitochondrial dysfunction pathway.

Agonist-induced Piezo1 activation promote mitochondrial-dependent apoptosis in vascular smooth muscle cells

OBJECTIVE

Mechanical damage plays an essential role in the progression of atherosclerosis. Piezo1 is a new mechanically sensitive ion channel. The present study investigated the vascular smooth muscle cells (VSMCs) apoptosis induced by Piezo1 activation and explored its underlying mechanism.

METHODS

We evaluated cell viability and apoptosis rate with cell counting kit-8 (CCK-8) and Annexin V-FITC/PI flow cytometry assay, respectively. And then Western blot was performed to measure the relative protein. Reactive oxygen species (ROS) and intracellular Ca²⁺ were assessed via fluorescence microscope, and the mitochondrial transmembrane potential was monitored by JC-10 staining.

RESULTS

Our in vitro study revealed that mice in the ApoE-/- group compared with control mice showed higher Piezo1 expression(P < 0.05). Besides, Yoda1, a Piezo1 agonist, triggered Ca²⁺ overload, mitochondrial damage, accumulation of ROS, and VSMCs apoptosis in a dose-depend manner. Furthermore, BAPT-AM (an intracellular Ca²⁺ chelator) and NAC (an antioxidant) suppressed the mitochondrial damage and attenuated the VSMCs apoptosis.

CONCLUSION

Our study suggested that Piezo1 induced VSMCs apoptosis because of Ca²⁺ overload, excessive ROS generation, and mitochondrial dysfunction, which indicated that Piezo1 has potential value in treating vascular diseases.

S1PR2/RhoA/ROCK1 pathway promotes inflammatory bowel disease by inducing intestinal vascular endothelial barrier damage and M1 macrophage polarization

Vascular and immune dysfunctions are thought to be related to the pathogenesis of inflammatory bowel disease (IBD), but behind this, the exact mechanism of mucosal vascular endothelial barrier dysfunction and macrophage phenotypic transition is not fully understood. Here, we explored the mechanistic role of sphingosine 1-phosphate receptor 2 (S1PR2) and its downstream G protein RhoA/Rho kinase 1 (ROCK1) signaling pathway in the intestinal endothelial barrier damage and M1 macrophage polarization in IBD. We found that the expression of S1PR2 in intestinal mucosal vascular endothelial cells and macrophages of IBD patients and DSS-induced colitis mice as well as vascular endothelial cells and macrophages treated with LPS in vitro was significantly increased. Knocking down or pharmacologically inhibiting S1PR2 significantly downregulated the expression of RhoA and ROCK1 in vascular endothelial cells and macrophages. Furthermore, inhibition of S1PR2 and ROCK1 reversed the impaired vascular barrier function and M1 macrophage polarization in vivo and in vitro, while reducing ER stress in vascular endothelial cells and glycolysis in macrophages. In addition, inhibition of ER stress or glycolysis reversed LPS-induced impairment of vascular endothelial cell barrier function and M1 macrophage polarization. Collectively, our results indicate that the S1PR2/RhoA/ROCK1 signaling pathway may participate in the pathogenesis of IBD by regulating vascular endothelial barrier function and M1 macrophage polarization.

Circular RNA_0033596 aggravates endothelial cell injury induced by oxidized low-density lipoprotein via microRNA-217-5p /chloride intracellular channel 4 axis

In recent years, the modulatory functions of some circular RNAs (circRNAs) in the pathogenesis of atherosclerosis (AS) have been reported. Nonetheless, the role of circular RNA_0033596 (circ_0033596) in AS and its mechanism remains unclarified. In this study, oxidized low-density lipoprotein (ox-LDL) was applied to treat human umbilical vein endothelial cells (HUVECs) to establish a cell model of endothelial cell injury. Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) were employed to detect the expression of circ_0033596, microRNA-217-5p (miR-217-5p), and chloride intracellular channel 4 (CLIC4) in HUVECs. The binding sites between circ_0033596 and miR-217-5p, as well as between miR-217-5p and CLIC4 mRNA 3ʹUTR were determined through a dual-luciferase reporter gene assay. It was found that circ_0033596 expression was increased in ox-LDL-induced HUVECs. After ox-LDL stimulation, HUVEC viability and cell cycle progression were inhibited, and the apoptosis was promoted, while circ_0033596 overexpression aggravated these effects. MiR-217-5p was identified as a downstream target of circ_0033596, and circ_0033596 negatively regulated miR-217-5p expression. CLIC4 was identified as miR-217-5p’s downstream target gene and could be positively modulated by circ_0033596. All in all circ_0033596 aggravates ox-LDL-induced HUVEC apoptosis by regulating the miR-217-5p/CLIC4 axis, by which circ_0033596 participates in the pathogenesis of AS.

Endoplasmic Reticulum-Mitochondria Contacts: A Potential Therapy Target for Cardiovascular Remodeling-Associated Diseases

Cardiovascular remodeling occurs in cardiomyocytes, collagen meshes, and vascular beds in the progress of cardiac insufficiency caused by a variety of cardiac diseases such as chronic ischemic heart disease, chronic overload heart disease, myocarditis, and myocardial infarction. The morphological changes that occur as a result of remodeling are the critical pathological basis for the occurrence and development of serious diseases and also determine morbidity and mortality. Therefore, the inhibition of remodeling is an important approach to prevent and treat heart failure and other related diseases. The endoplasmic reticulum (ER) and mitochondria are tightly linked by ER-mitochondria contacts (ERMCs). ERMCs play a vital role in different signaling pathways and provide a satisfactory structural platform for the ER and mitochondria to interact and maintain the normal function of cells, mainly by involving various cellular life processes such as lipid metabolism, calcium homeostasis, mitochondrial function, ER stress, and autophagy. Studies have shown that abnormal ERMCs may promote the occurrence and development of remodeling and participate in the formation of a variety of cardiovascular remodeling-associated diseases. This review focuses on the structure and function of the ERMCs, and the potential mechanism of ERMCs involved in cardiovascular remodeling, indicating that ERMCs may be a potential target for new therapeutic strategies against cardiovascular remodeling-induced diseases.

PACS-2 attenuates diabetic kidney disease via the enhancement of mitochondria-associated endoplasmic reticulum membrane formation

The altered homeostasis of mitochondria-associated endoplasmic reticulum (ER) membranes (MAM) was closely associated with the pathological process of nervous system diseases and insulin resistance. Here, the exact implication of phosphofurin acidic cluster sorting protein 2 (PCAS-2), an anchor protein in the MAM interface, in diabetic kidney disease was investigated. In the kidneys of type 1 and type 2 diabetes mice and HG-induced HK-2 cells, a notable disruption of ER-mitochondria interactions, accompanied by a decreased PACS-2 expression in all subcellular fractions. Furthermore, PACS-2 knockout mice with diabetes displayed accelerated development of proteinuria, deterioration of kidney function, and aggravated disruption of MAM area, ER stress, mitochondrial dysfunction, renal apoptosis, and fibrosis. However, overexpression of PACS-2 effectively protected diabetic kidneys and HG-treated HK-2 cells from renal tubular impairments. Importantly, experimental uncoupling of ER-mitochondria contacts reversed the protective effects of PACS-2 restoration on HK-2 cells under HG conditions. In summary, our data indicate a pivotal role of PACS-2 in the development of diabetic renal tubular injury via the stabilization of MAM.

Cellular senescence links mitochondria-ER contacts and aging

Membrane contact sites emerged in the last decade as key players in the integration, regulation and transmission of many signals within cells, with critical impact in multiple pathophysiological contexts. Numerous studies accordingly point to a role for mitochondria-endoplasmic reticulum contacts (MERCs) in modulating aging. Nonetheless, the driving cellular mechanisms behind this role remain unclear. Recent evidence unravelled that MERCs regulate cellular senescence, a state of permanent proliferation arrest associated with a pro-inflammatory secretome, which could mediate MERC impact on aging. Here we discuss this idea in light of recent advances supporting an interplay between MERCs, cellular senescence and aging.

Subclinical Vascular Damage: Current Insights and Future Potential

The cardiovascular risk assessment must be carried out during all the different phases of life because the cardiovascular risk and the related prevention actions are dynamic and constantly evolving. As patients age, they change their exposure to various risk factors and accumulate comorbidities by changing their subjective cardiovascular risk, so it is necessary to undertake personalized early and preventive diagnostic actions. The main approach to asymptomatic vascular disease is based on primary prevention with the adoption of a healthy lifestyle. Indeed, lifestyle influences most of the traditional risk factors. In recent years, important differences between the sexes regarding cardiovascular risk factors have emerged and in particular, risk factors specific for female sex have been identified. Women are more likely to be categorized into lower risk categories for cardiovascular disease and, as a result, receive less lifestyle counseling than men, as well as less intensive prevention. This narrative review aims to analyze CVD risk prevention in asymptomatic atherosclerosis with a look at new emerging factors. In the end, we quickly analyzed the effects of the recent pandemic on lifestyle and cardiovascular risk and the potential negative effects in the long term.

Targeting senescent cells for vascular aging and related diseases

Cardiovascular diseases are a serious threat to human health, especially in the elderly. Vascular aging makes people more susceptible to cardiovascular diseases due to significant dysfunction or senescence of vascular cells and maladaptation of vascular structure and function; moreover, vascular aging is currently viewed as a modifiable cardiovascular risk factor. To emphasize the relationship between senescent cells and vascular aging, we first summarize the roles of senescent vascular cells (endothelial cells, smooth muscle cells and immune cells) in the vascular aging process and inducers that contribute to cellular senescence. Then, we present potential strategies for directly targeting senescent cells (senotherapy) or preventively targeting senescence inducers (senoprevention) to delay vascular aging and the development of age-related vascular diseases. Finally, based on recent research, we note some important questions that still need to be addressed in the future.

Molecular Dysfunctions of Mitochondria-Associated Endoplasmic Reticulum Contacts in Atherosclerosis

Atherosclerosis is a chronic lipid-driven inflammatory disease that results in the formation of lipid-rich and immune cell-rich plaques in the arterial wall, which has high morbidity and mortality in the world. The mechanism of atherosclerosis is still unclear now. Potential hypotheses involved in atherosclerosis are chronic inflammation theory, lipid percolation theory, mononuclear-macrophage theory, endothelial cell (EC) injury theory, and smooth muscle cell (SMC) mutation theory. Changes of phospholipids, glucose, critical proteins, etc. on mitochondria-associated endoplasmic reticulum membrane (MAM) can cause the progress of atherosclerosis. This review describes the structural and functional interaction between mitochondria and endoplasmic reticulum (ER) and explains the role of critical molecules in the structure of MAM during atherosclerosis.

Novel Insights and Current Evidence for Mechanisms of Atherosclerosis: Mitochondrial Dynamics as a Potential Therapeutic Target

Cardiovascular disease (CVD) is the main cause of death worldwide. Atherosclerosis is the underlying pathological basis of CVD. Mitochondrial homeostasis is maintained through the dynamic processes of fusion and fission. Mitochondria are involved in many cellular processes, such as steroid biosynthesis, calcium homeostasis, immune cell activation, redox signaling, apoptosis, and inflammation, among others. Under stress conditions, mitochondrial dynamics, mitochondrial cristae remodeling, and mitochondrial ROS (mitoROS) production increase, mitochondrial membrane potential (MMP) decreases, calcium homeostasis is imbalanced, and mitochondrial permeability transition pore open (mPTP) and release of mitochondrial DNA (mtDNA) are activated. mtDNA recognized by TLR9 can lead to NF-κB pathway activation and pro-inflammatory factor expression. At the same time, TLR9 can also activate NLRP3 inflammasomes and release interleukin, an event that eventually leads to tissue damage and inflammatory responses. In addition, mitochondrial dysfunction may amplify the activation of NLRP3 through the production of mitochondrial ROS, which together aggravate accumulating mitochondrial damage. In addition, mtDNA defects or gene mutation can lead to mitochondrial oxidative stress. Finally, obesity, diabetes, hypertension and aging are risk factors for the progression of CVD, which are closely related to mitochondrial dynamics. Mitochondrial dynamics may represent a new target in the treatment of atherosclerosis. Antioxidants, mitochondrial inhibitors, and various new therapies to correct mitochondrial dysfunction represent a few directions for future research on therapeutic intervention and amelioration of atherosclerosis.

Miro proteins connect mitochondrial function and intercellular transport

Mitochondria are organelles present in most eukaryotic cells, where they play major and multifaceted roles. The classical notion of the main mitochondrial function as the powerhouse of the cell per se has been complemented by recent discoveries pointing to mitochondria as organelles affecting a number of other auxiliary processes. They go beyond the classical energy provision via acting as a relay point of many catabolic and anabolic processes, to signaling pathways critically affecting cell growth by their implication in de novo pyrimidine synthesis. These additional roles further underscore the importance of mitochondrial homeostasis in various tissues, where its deregulation promotes a number of pathologies. While it has long been known that mitochondria can move within a cell to sites where they are needed, recent research has uncovered that mitochondria can also move between cells. While this intriguing field of research is only emerging, it is clear that mobilization of mitochondria requires a complex apparatus that critically involves mitochondrial proteins of the Miro family, whose role goes beyond the mitochondrial transfer, as will be covered in this review.

Endolysosomal Ca2+ signaling in cardiovascular health and disease

An increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) regulates a plethora of functions in the cardiovascular (CV) system, including contraction in cardiomyocytes and vascular smooth muscle cells (VSMCs), and angiogenesis in vascular endothelial cells and endothelial colony forming cells. The sarco/endoplasmic reticulum (SR/ER) represents the largest endogenous Ca²⁺ store, which releases Ca²⁺ through ryanodine receptors (RyRs) and/or inositol-1,4,5-trisphosphate receptors (InsP₃Rs) upon extracellular stimulation. The acidic vesicles of the endolysosomal (EL) compartment represent an additional endogenous Ca²⁺ store, which is targeted by several second messengers, including nicotinic acid adenine dinucleotide phosphate (NAADP) and phosphatidylinositol 3,5-bisphosphate [PI(3,5)P₂], and may release intraluminal Ca²⁺ through multiple Ca²⁺ permeable channels, including two-pore channels 1 and 2 (TPC1-2) and Transient Receptor Potential Mucolipin 1 (TRPML1). Herein, we discuss the emerging, pathophysiological role of EL Ca²⁺ signaling in the CV system. We describe the role of cardiac TPCs in β-adrenoceptor stimulation, arrhythmia, hypertrophy, and ischemia-reperfusion injury. We then illustrate the role of EL Ca²⁺ signaling in VSMCs, where TPCs promote vasoconstriction and contribute to pulmonary artery hypertension and atherosclerosis, whereas TRPML1 sustains vasodilation and is also involved in atherosclerosis. Subsequently, we describe the mechanisms whereby endothelial TPCs promote vasodilation, contribute to neurovascular coupling in the brain and stimulate angiogenesis and vasculogenesis. Finally, we discuss about the possibility to target TPCs, which are likely to mediate CV cell infection by the Severe Acute Respiratory Disease-Coronavirus-2, with Food and Drug Administration-approved drugs to alleviate the detrimental effects of Coronavirus Disease-19 on the CV system.

Mitochondria-associated membrane-modulated Ca2+ transfer: A potential treatment target in cardiac ischemia reperfusion injury and heart failure

Effective Ca²⁺ dependent mitochondrial energy supply is imperative for proper cardiac contractile activity, while disruption of Ca²⁺ homeostasis participates in the pathogenesis of multiple human diseases. This phenomenon is particularly prominent in cardiac ischemia and reperfusion (I/R) and heart failure, both of which require strict clinical intervention. The interface between endoplasmic reticula (ER) and mitochondria, designated the mitochondria-associated membrane (MAM), is now regarded as a crucial mediator of Ca²⁺ transportation. Thus, interventions targeting this physical and functional coupling between mitochondria and the ER are highly desirable. Increasing evidence supports the notion that restoration, and maintenance, of the physiological contact between these two organelles can improve mitochondrial function, while inhibiting cell death, thereby sufficiently ameliorating I/R injury and heart failure development. A better understanding regarding the underlying mechanism of MAM-mediated transport will pave the way for identification of novel treatment approaches for heart disease. Therefore, in this review, we summarize the crucial functions and potential mechanisms of MAMs in the pathogenesis of I/R and heart failure.

The Mitochondrial-associated ER membrane (MAM) compartment and its dysregulation in Amyotrophic Lateral Sclerosis (ALS)

The endoplasmic reticulum (ER) and mitochondria connect at multiple contact sites to form a unique cellular compartment, termed the 'mitochondria-associated ER membranes' (MAMs). MAMs are hubs for signalling pathways that regulate cellular homeostasis and survival, metabolism, and sensitivity to apoptosis. MAMs are therefore involved in vital cellular functions, but they are dysregulated in several human diseases. Whilst MAM dysfunction is increasingly implicated in the pathogenesis of neurodegenerative diseases, its role in amyotrophic lateral sclerosis (ALS) is poorly understood. However, in ALS both ER and mitochondrial dysfunction are well documented pathophysiological events. Moreover, alterations to lipid metabolism in neurons regulate processes linked to neurodegenerative diseases, and a link between dysfunction of lipid metabolism and ALS has also been proposed. In this review we discuss the structural and functional relevance of MAMs in ALS and how targeting MAM could be therapeutically beneficial in this disorder.

Role of sphingosine-1-phosphate receptors in vascular injury of inflammatory bowel disease

Sphingosine‐1‐phosphate receptors (S1PRs) have an impact on the intestinal inflammation of inflammatory bowel disease (IBD) by regulating lymphocyte migration and differentiation. S1PR modulators as an emerging therapeutic approach are being investigated for the treatment of IBD. However, the role of S1PRs in intestinal vessels has not drawn much attention. Intestinal vascular damage is one of the major pathophysiological features of IBD, characterized by increased vascular density and impaired barrier function. S1PRs have pleiotropic effects on vascular endothelial cells, including proliferation, migration, angiogenesis and barrier homeostasis. Mounting evidence shows that S1PRs are abnormally expressed on intestinal vascular endothelial cells in IBD. Unexpectedly, S1PR modulators may damage intestinal vasculature, for example increase intestinal bleeding; therefore, S1PRs are thought to be involved in the regulation of intestinal vascular function in IBD. However, little is understood about how S1PRs regulate intestinal vascular function and participate in the initiation and progression of IBD. In this review, we summarize the pathogenic role of S1PRs in and the underlying mechanisms behind the intestinal vascular injury in IBD in order for improving IBD practice including S1PR‐targeted therapies.

Central role of TRAP1 in the ameliorative effect of oleanolic acid on the mitochondrial-mediated and endoplasmic reticulum stress-excitated apoptosis induced by ochratoxin A

Ochratoxin A (OTA) is a nephrotoxic mycotoxin that is widely distributed in foodstuffs and feeds, meanwhile oleanolic acid (OA) is ubiquitous in various fruit skins, food materials, and medicinal herbs. Due to that OA has a nephroprotective effect, it has the poteintial to counteract OTA-induced nephrotoxicity by nutritional intervention of OA. Furthermore, tumor necrosis factor receptor-associated protein 1 (TRAP1) acts as the core of endoplasmic reticulum (ER)-mitochondria crosstalk, becoming our focus in the mechanism investigation. In this study, the cell viability, apoptosis rate, and protein expressions of human proximal tubule epithelial-originated kidney-2 (HK-2) cells in response to OTA and/or OA were determined. Results indicated that a 24 h-treatment of 1-5 μM OTA could notably induce mitochondrial-mediated and ER stress (ERS)-excitated apoptosis via inhibiting TRAP1, thereby activating CypD, Bax, Cyt-C, Cleaved Caspase-9, Cleaved Caspase-3, GRP78, p-PERK, p-eIF2α, ATF4, and CHOP and inhibiting Bcl-2 (P < 0.05). Results of the RNA interference of TRAP1 further ascertained its anti-apoptotic function via inhibiting CypD, Bax, GRP78, and CHOP and enhancing Bcl-2 (P < 0.05). The pre-treatment of 2 μM OA for 2 h could remarkably relieve OTA-induced suppression of TRAP1 (P < 0.05). In conclusion, TRAP1 played a central role in the ameliorative effect of OA on the mitochondrial-mediated and ERS-excitated apoptosis induced by OTA.

MAMs Protect Against Ectopic Fat Deposition and Lipid-Related Kidney Damage in DN Patients

Ectopic fat deposition (EFD) in the kidney plays a key role in the development of diabetic nephropathy (DN). Mitochondria-associated ER membranes (MAMs) are structures that connect to the endoplasmic reticulum (ER) and are involved in lipid metabolism. However, there are few studies on MAMs in the field of kidney disease, and the relationship between EFD and MAMs in DN is still unclear. In this study, increased EFD in the kidneys of DN patients was observed, and analysis showed that the degree of EFD was positively correlated with renal damage. Then, the MAMs were quantified by an in situ proximity ligation assay (PLA). The MAMs in the kidneys were found to gradually decrease through the different stages of DN, while the expression of ADRP (a marker of lipid droplets) and tubulointerstitial damage increased. Moreover, correlation analysis showed that the MAMs were negatively correlated with serum lipid levels, the EFD in the kidney and renal damage. Finally, we observed decreased expression of MAM-control proteins (DsbA-L, PACS-2, and MFN-2) in different stages of DN and they were associated with lipid deposition and renal damage. These data showed that the destruction of MAMs in DN might be the cause of EFD and interstitial damage in the kidney.

ER-Mitochondria Contacts and Insulin Resistance Modulation through Exercise Intervention

The endoplasmic reticulum (ER) makes physical contacts with mitochondria at specific sites, and the hubs between the two organelles are called mitochondria-associated ER membranes (MAMs). MAMs are known to play key roles in biological processes, such as intracellular Ca²⁺ regulation, lipid trafficking, and metabolism, as well as cell death, etc. Studies demonstrated that dysregulation of MAMs significantly contributed to insulin resistance. Alterations of MAMs’ juxtaposition and integrity, impaired expressions of insulin signaling molecules, disruption of Ca²⁺ homeostasis, and compromised metabolic flexibility are all actively involved in the above processes. In addition, exercise training is considered as an effective stimulus to ameliorate insulin resistance. Although the underlying mechanisms for exercise-induced improvement in insulin resistance are not fully understood, MAMs may be critical for the beneficial effects of exercise.

Mitochondria-Associated Endoplasmic Reticulum Membranes in Cardiovascular Diseases

The endoplasmic reticulum (ER) and mitochondria are physically connected to form dedicated structural domains known as mitochondria-associated ER membranes (MAMs), which participate in fundamental biological processes, including lipid and calcium (Ca²⁺) homeostasis, mitochondrial dynamics and other related cellular behaviors such as autophagy, ER stress, inflammation and apoptosis. Many studies have proved the importance of MAMs in maintaining the normal function of both organelles, and the abnormal amount, structure or function of MAMs is related to the occurrence of cardiovascular diseases. Here, we review the knowledge regarding the components of MAMs according to their different functions and the specific roles of MAMs in cardiovascular physiology and pathophysiology, focusing on some highly prevalent cardiovascular diseases, including ischemia-reperfusion, diabetic cardiomyopathy, heart failure, pulmonary arterial hypertension and systemic vascular diseases. Finally, we summarize the possible mechanisms of MAM in cardiovascular diseases and put forward some obstacles in the understanding of MAM function we may encounter.

The Molecular Determinants of Mitochondrial Membrane Contact With ER, Lysosomes and Peroxisomes in Neuronal Physiology and Pathology

Membrane tethering is an important communication method for membrane-packaged organelles. Mitochondria are organelles with a bilayer membrane, and the membrane contact between mitochondria and other organelles is indispensable for maintaining cellular homeostasis. Increased levels of molecular determinants that mediate the membrane contact between mitochondria and other organelles, and their functions, have been revealed in recent years. In this review article, we aim to summarize the findings on the tethering between mitochondria and other organelles in physiological or pathological conditions, and discuss their roles in cellular homeostasis, neural activity, and neurodegenerative diseases.

Photodynamic therapy regulates fate of cancer stem cells through reactive oxygen species

Photodynamic therapy (PDT) is an effective and promising cancer treatment. PDT directly generates reactive oxygen species (ROS) through photochemical reactions. This oxygen-dependent exogenous ROS has anti-cancer stem cell (CSC) effect. In addition, PDT may also increase ROS production by altering metabolism, endoplasmic reticulum stress, or potential of mitochondrial membrane. It is known that the half-life of ROS in PDT is short, with high reactivity and limited diffusion distance. Therefore, the main targeting position of PDT is often the subcellular localization of photosensitizers, which is helpful for us to explain how PDT affects CSC characteristics, including differentiation, self-renewal, apoptosis, autophagy, and immunogenicity. Broadly speaking, excess ROS will damage the redox system and cause oxidative damage to molecules such as DNA, change mitochondrial permeability, activate unfolded protein response, autophagy, and CSC resting state. Therefore, understanding the molecular mechanism by which ROS affect CSCs is beneficial to improve the efficiency of PDT and prevent tumor recurrence and metastasis. In this article, we review the effects of two types of photochemical reactions on PDT, the metabolic processes, and the biological effects of ROS in different subcellular locations on CSCs.

Nicotinic acid adenine dinucleotide phosphate activates two-pore channel TPC1 to mediate lysosomal Ca2+ release in endothelial colony-forming cells

Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most recently discovered Ca²⁺ -releasing messenger that increases the intracellular Ca²⁺ concentration by mobilizing the lysosomal Ca²⁺ store through two-pore channels 1 (TPC1) and 2 (TPC2). NAADP-induced lysosomal Ca²⁺ release regulates multiple endothelial functions, including nitric oxide release and proliferation. A sizeable acidic Ca²⁺ pool endowed with TPC1 is also present in human endothelial colony-forming cells (ECFCs), which represent the only known truly endothelial precursors. Herein, we sought to explore the role of the lysosomal Ca²⁺ store and TPC1 in circulating ECFCs by harnessing Ca²⁺ imaging and molecular biology techniques. The lysosomotropic agent, Gly-Phe β-naphthylamide, and nigericin, which dissipates the proton gradient which drives Ca²⁺ sequestration by acidic organelles, caused endogenous Ca²⁺ release in the presence of a replete inositol-1,4,5-trisphosphate (InsP₃ )-sensitive endoplasmic reticulum (ER) Ca²⁺ pool. Likewise, the amount of ER releasable Ca²⁺ was reduced by disrupting lysosomal Ca²⁺ content. Liposomal delivery of NAADP induced a transient Ca²⁺ signal that was abolished by disrupting the lysosomal Ca²⁺ store and by pharmacological and genetic blockade of TPC1. Pharmacological manipulation revealed that NAADP-induced Ca²⁺ release also required ER-embedded InsP₃ receptors. Finally, NAADP-induced lysosomal Ca²⁺ release was found to trigger vascular endothelial growth factor-induced intracellular Ca²⁺ oscillations and proliferation, while it did not contribute to adenosine-5'-trisphosphate-induced Ca²⁺ signaling. These findings demonstrated that NAADP-induced TPC1-mediated Ca²⁺ release can selectively be recruited to induce the Ca²⁺ response to specific cues in circulating ECFCs.

Mitochondrial Dysfunction and DNA Damage in the Context of Pathogenesis of Atherosclerosis

Atherosclerosis is a multifactorial disease of the cardiovascular system associated with aging, inflammation, and oxidative stress. An important role in the development of atherosclerosis play elevated plasma lipoproteins. A number of external factors (smoking, diabetes, infections) can also contribute to the development of the disease. For a long time, atherosclerosis remains asymptomatic, therefore, the search for early markers of the disease is critical for the timely management and better outcomes for patients. Mitochondrial dysfunction and mitochondrial DNA (mtDNA) damage appear to connect different aspects of atherosclerosis pathogenesis. To date, multiple lines of research have demonstrated the strong association of mitochondrial dysfunction with the development of various human diseases. Therapies aimed at restoring the mitochondrial function are being actively developed, and are expected to broaden the therapeutic possibilities for several chronic human diseases. The development of such therapies depends on our understanding of the functional roles of different mtDNA variants associated with one or another disorder, and the molecular mechanisms linking mitochondrial dysfunction with a given pathological feature. These questions are, however, challenging and require future intensive research. This review summarizes the recent studies and describes the central processes of the development of atherosclerosis, and shows their relationship with mitochondrial dysfunction. One of the promising therapeutic approaches for future atherosclerosis treatments is the use of mitochondria-targeted antioxidants. Future studies should focus on characterizing the mechanisms of mitochondrial involvement in cardiovascular pathologies to better direct the search for novel therapies.

Roles of VMP1 in Autophagy and ER-Membrane Contact: Potential Implications in Neurodegenerative Disorders

Cellular communication processes are highly dynamic and mediated, at least in part, by contacts between various membrane structures. The endoplasmic reticulum (ER), the major biosynthetic organelle of the cell, establishes an extensive network with other membrane structures to regulate the transport of intracellular molecules. Vacuole membrane protein 1 (VMP1), an ER-localized metazoan-specific protein, plays important roles in the formation of autophagosomes and communication between the ER and other organelles, including mitochondria, autophagosome precursor membranes, Golgi, lipid droplets, and endosomes. Increasing evidence has indicated that autophagy and ER–membrane communication at membrane contact sites are closely related to neurodegenerative disorders, such as Parkinson’s disease, Alzheimer’s disease, and amyotrophic lateral sclerosis. In this review, we summarize the roles of VMP1 in autophagy and ER–membrane contacts and discuss their potential implications in neurodegenerative disorders.

The role of mitochondria-associated membranes in cellular homeostasis and diseases

Mitochondria and endoplasmic reticulum (ER) are fundamental in the control of cell physiology regulating several signal transduction pathways. They continuously communicate exchanging messages in their contact sites called MAMs (mitochondria-associated membranes). MAMs are specific microdomains acting as a platform for the sorting of vital and dangerous signals. In recent years increasing evidence reported that multiple scaffold proteins and regulatory factors localize to this subcellular fraction suggesting MAMs as hotspot signaling domains. In this review we describe the current knowledge about MAMs' dynamics and processes, which provided new correlations between MAMs' dysfunctions and human diseases. In fact, MAMs machinery is strictly connected with several pathologies, like neurodegeneration, diabetes and mainly cancer. These pathological events are characterized by alterations in the normal communication between ER and mitochondria, leading to deep metabolic defects that contribute to the progression of the diseases.

Astragaloside IV inhibits oxidized low‑density lipoprotein‑induced endothelial damage via upregulation of miR‑140‑3p

Oxidized low‑density lipoprotein (ox‑LDL)‑mediated endothelial cell injury has an important role in the vascular complications of type 2 diabetes. Astragaloside IV (ASV) is an active component of Radix Astragali, which has been demonstrated to exert protective effects against endothelial damage. The present study explored whether microRNAs (miRNAs) are involved in mediating the protective effects of ASV on ox‑LDL‑induced damage in human umbilical vein endothelial cells (HUVECs). RNA sequencing and reverse transcription‑quantitative PCR analyses revealed that ox‑LDL treatment significantly downregulated miR‑140‑3p expression in HUVECs. miR‑140‑3p overexpression promoted cell proliferation and inhibited apoptosis in ox‑LDL‑induced HUVECs. However, inhibition of miR‑140‑3p expression could reverse the effects of ASV on ox‑LDL‑induced HUVECs and reactivate ASV‑inhibited PI3K/Akt signaling in ox‑LDL‑induced HUVECs. In addition, Krüppel‑like factor 4 (KLF4) was identified as a target of miR‑140‑3p in ox‑LDL‑treated HUVECs. Subsequent experiments revealed that KLF4 overexpression partially counteracted the protective effects of miR‑140‑3p or ASV treatment in ox‑LDL‑induced HUVECs. Taken together, the current findings demonstrated that the protective effects of ASV on HUVECs were dependent on miR‑140‑3p upregulation and subsequent inhibition of KLF4 expression, which in turn suppressed the PI3K/Akt signaling pathway. The present results shed light to the molecular mechanism by which ASV alleviated ox‑LDL‑induced endothelial cell damage.

Design, Synthesis, and Anticancer Effect Studies of Iridium(III) Polypyridyl Complexes against SGC-7901 Cells

Three iridium(III) complexes ([Ir(Hppy)₂(L)](PF₆) (Hppy = 2-phenylpyridine, L = 5-nitrophenanthroline, NP), 1; 5-nitro-6-amino-phenanthroline (NAP), 2; and 5,6-diamino-phenanthroline (DAP) 3 were synthesized and characterized. The cytotoxicities of Ir(III) complexes 1–3 against cancer cell lines SGC-7901, A549, HeLa, Eca-109, HepG2, BEL-7402, and normal NIH 3T3 cells were investigated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT) method. The results showed that the three iridium(III) complexes had moderate in vitro anti-tumor activity toward SGC-7901 cells with IC₅₀ values of 3.6 ± 0.1 µM for 1, 14.1 ± 0.5 µM for 2, and 11.1 ± 1.3 µM for 3. Further studies showed that 1–3 induce cell apoptosis/death through DNA damage, cell cycle arrest at the S or G0/G1 phase, ROS elevation, increased levels of Ca²⁺, high mitochondrial membrane depolarization, and cellular ATP depletion. Transwell and Colony-Forming assays revealed that complexes 1–3 can also effectively inhibit the metastasis and proliferation of tumor cells. These results demonstrate that 1–3 induce apoptosis in SGC-7901 cells through ROS-mediated mitochondrial damage and DNA damage pathways, as well as by inhibiting cell invasion, thereby exerting anti-tumor cell proliferation activity in vitro.