Mitochondrial Fusion Promoter Alleviates Brain Damage in Rats with Cardiac Ischemia/Reperfusion Injury

TMEM135 maintains the equilibrium of osteogenesis and adipogenesis by regulating mitochondrial dynamics

BACKGROUND

Disturbance in the differentiation process of bone marrow mesenchymal stem cells (BMSCs) leads to osteoporosis. Mitochondrial dynamics plays a pivotal role in the metabolism and differentiation of BMSCs. However, the mechanisms underlying mitochondrial dynamics and their impact on the differentiation equilibrium of BMSCs remain unclear.

METHODS

We investigated the mitochondrial morphology and markers related to mitochondrial dynamics during BMSCs osteogenic and adipogenic differentiation. Bioinformatics was used to screen potential genes regulating BMSCs differentiation through mitochondrial dynamics. Subsequently, we evaluated the impact of Transmembrane protein 135 (TMEM135) deficiency on bone homeostasis by comparing Tmem135 knockout mice with their littermates. The mechanism of TMEM135 in mitochondrial dynamics and BMSCs differentiation was also investigated in vivo and in vitro.

RESULTS

Distinct changes in mitochondrial morphology were observed between osteogenic and adipogenic differentiation of BMSCs, manifesting as fission in the late stage of osteogenesis and fusion in adipogenesis. Additionally, we revealed that TMEM135, a modulator of mitochondrial dynamics, played a functional role in regulating the equilibrium between adipogenesis and osteogenesis. The TMEM135 deficiency impaired mitochondrial fission and disrupted crucial mitochondrial energy metabolism during osteogenesis. Tmem135 knockout mice showed osteoporotic phenotype, characterized by reduced osteogenesis and increased adipogenesis. Mechanistically, TMEM135 maintained intracellular calcium ion homeostasis and facilitated the dephosphorylation of dynamic-related protein 1 at Serine 637 in BMSCs.

CONCLUSIONS

Our findings underscore the significant role of TMEM135 as a modulator in orchestrating the differentiation trajectory of BMSCs and promoting a shift in mitochondrial dynamics toward fission. This ultimately contributes to the osteogenesis process. This work has provided promising biological targets for the treatment of osteoporosis.

Communication Regarding the Myocardial Ischemia/Reperfusion and Cognitive Impairment: A Narrative Literature Review

Coronary artery disease is a prevalent ischemic disease that results in insufficient blood supply to the heart muscle due to narrowing or occlusion of the coronary arteries. Various reperfusion strategies, including pharmacological thrombolysis and percutaneous coronary intervention, have been developed to enhance blood flow restoration. However, these interventions can lead to myocardial ischemia/reperfusion injury (MI/RI), which can cause unpredictable complications. Recent research has highlighted a compelling association between MI/RI and cognitive function, revealing pathophysiological mechanisms that may explain altered brain cognition. Manifestations in the brain following MI/RI exhibit pathological features resembling those observed in Alzheimer's disease (AD), implying a potential link between MI/RI and the development of AD. The pro-inflammatory state following MI/RI may induce neuroinflammation via systemic inflammation, while impaired cardiac function can result in cerebral under-perfusion. This review delves into the role of extracellular vesicles in transporting deleterious substances from the heart to the brain during conditions of MI/RI, potentially contributing to impaired cognition. Addressing the cognitive consequence of MI/RI, the review also emphasizes potential neuroprotective interventions and pharmacological treatments within the MI/RI model. In conclusion, the review underscores the significant impact of MI/RI on cognitive function, summarizes potential mechanisms of cardio-cerebral communication in the context of MI/RI, and offers ideas and insights for the prevention and treatment of cognitive dysfunction following MI/RI.

Modulating Mitochondrial Dynamics Mitigates Cognitive Impairment in Rats with Myocardial Infarction

BACKGROUND

We have previously demonstrated that oxidative stress and brain mitochondrial dysfunction are key mediators of brain pathology during myocardial infarction (MI).

OBJECTIVE

To investigate the beneficial effects of mitochondrial dynamic modulators, including mitochondrial fission inhibitor (Mdivi-1) and mitochondrial fusion promotor (M1), on cognitive function and molecular signaling in the brain of MI rats in comparison with the effect of enalapril.

METHODS

Male rats were assigned to either sham or MI operation. In the MI group, rats with an ejection Fraction less than 50% were included, and then they received one of the following treatments for 5 weeks: vehicle, enalapril, Mdivi-1, or M1. Cognitive function was tested, and the brains were used for molecular study.

RESULTS

MI rats exhibited cardiac dysfunction with systemic oxidative stress. Cognitive impairment was found in MI rats, along with dendritic spine loss, blood-brain barrier (BBB) breakdown, brain mitochondrial dysfunction, and decreased mitochondrial and increased glycolysis metabolism, without the alteration of APP, BACE-1, Tau and p-Tau proteins. Treatment with Mdivi-1, M1, and enalapril equally improved cognitive function in MI rats. All treatments decreased dendritic spine loss, brain mitochondrial oxidative stress, and restored mitochondrial metabolism. Brain mitochondrial fusion was recovered only in the Mdivi-1-treated group.

CONCLUSION

Mitochondrial dynamics modulators improved cognitive function in MI rats through a reduction of systemic oxidative stress and brain mitochondrial dysfunction and the enhancement of mitochondrial metabolism. In addition, this mitochondrial fission inhibitor increased mitochondrial fusion in MI rats.

Mitochondrial Fusion Promoter Given During Ischemia Has Greater Neuroprotective Efficacy Than When Given at Onset of Reperfusion in Rats with Cardiac Ischemia/Reperfusion Injury

BACKGROUND

Cardiac ischemia/reperfusion (I/R) injury has been shown to impose deleterious effects not only on the heart but also on the brain. Our previous study demonstrated that pretreatment with a mitochondrial fusion promoter (M1) provided central neuroprotective effects following cardiac I/R injury.

OBJECTIVE

To investigate the effects of M1 given during the ischemic phase and M1 given at the beginning of reperfusion on brain pathologies following cardiac I/R.

METHODS

Male Wistar rats were randomly divided into either a sham operation (n = 6) or cardiac I/R injury (n = 18) group. Rats with cardiac I/R injury were then randomly divided into 3 subgroups: 1) Control, 2) M1 treatment during cardiac ischemia (2 mg/kg, intravenous (i.v.)), and 3) M1 treatment at the beginning of reperfusion (2 mg/kg, i.v.). After euthanasia, the brain of each rat was removed for further analysis.

RESULTS

Cardiac I/R injury caused brain mitochondrial dynamic imbalance, brain mitochondrial dysfunction, brain apoptosis, microglial dysmorphology, brain inflammation, tau hyperphosphorylation, and synaptic dysplasticity. M1 treatment at both time points effectively improved these parameters. M1 given during the ischemic phase had greater efficacy with regard to preventing brain mitochondrial dysfunction and suppressing brain inflammation, when compared to M1 given at the beginning of reperfusion.

CONCLUSIONS

Our findings suggest that treatment with this mitochondrial fusion promoter prevents mitochondrial dynamic imbalance in the brain of rats with cardiac I/R injury, thereby attenuating brain pathologies. Interestingly, giving the mitochondrial fusion promoter during the ischemic phase exerted greater neuroprotection than if given at the beginning of reperfusion.

Differential temporal therapies with pharmacologically targeted mitochondrial fission/fusion protect the brain against acute myocardial ischemia-reperfusion injury in prediabetic rats: The crosstalk between mitochondrial apoptosis and inflammation

An imbalance of brain mitochondrial dynamics, increases in brain inflammation and apoptosis, and increasing cognitive dysfunction, have been reported as being associated with prediabetes and myocardial ischemia-reperfusion (IR) injury. Since inhibiting mitochondrial fission with Mdivi-1 or promoting fusion with M1 had cardioprotective effects in myocardial IR injury and obesity, the neuroprotective roles of Mdivi-1 and M1 when administered at different time points of myocardial IR injury in obese prediabetes have never been determined. Ninety-six male Wistar rats were fed with either a normal (ND: n = 8) or a high-fat diet to induce prediabetes (HFD: n = 88) for 12 weeks. At week 13, all rats were subjected to left anterior descending coronary artery ligation for 30 min, followed by reperfusion for 120 min. HFD rats were randomly divided into 10 groups and assigned into either a pre-ischemic group treated with vehicle (HFV), pre-ischemic, during-ischemic, or onset of reperfusion groups treated with either Mdivi-1 (MDV), M1, or combined (COM). Heart function was examined invasively, with the heart being terminated to investigate myocardial infarction. Brains were collected to determine mitochondrial functions, inflammation, apoptosis, and pathological markers. Mdivi-1, M1, and COM treatment at different periods exerted cardioprotection against myocardial IR injury in HFD-fed rats by reducing infarct size and left ventricular dysfunction. All interventions also improved all brain pathologies against myocardial IR injury in prediabetic rats. These findings suggest that differential temporal modulation of mitochondrial dynamics may be appropriate regimens for preventing heart and brain complications after myocardial IR injury in obese prediabetes.

Acute administration of myeloid differentiation factor 2 inhibitor and N-acetyl cysteine attenuate brain damage in rats with cardiac ischemia/reperfusion injury

Inflammation and oxidative stress are mechanisms which potentially underlie the brain damage that can occur after cardiac ischemic and reperfusion (I/R) injury. 2i-10 is a new anti-inflammatory agent, acting via direct inhibition of myeloid differentiation factor 2 (MD2). However, the effects of 2i-10 and the antioxidant N-acetylcysteine (NAC) on pathologic brain in cardiac I/R injury are unknown. We hypothesized that 2i-10 and NAC offer similar neuroprotection levels against dendritic spine reduction through attenuation of brain inflammation, loss of tight junction integrity, mitochondrial dysfunction, reactive gliosis, and suppression of AD protein expression in rats with cardiac I/R injury. Male rats were allocated to either sham or acute cardiac I/R group (30 min of cardiac ischemia and 120 min of reperfusion). Rats in cardiac I/R group were given one of following treatments intravenously at the onset of reperfusion: vehicle, 2i-10 (20 or 40 mg/kg), and NAC (75 or 150 mg/kg). The brain was then used to determine biochemical parameters. Cardiac I/R led to cardiac dysfunction with dendritic spine loss, loss of tight junction integrity, brain inflammation, and mitochondrial dysfunction. Treatment with 2i-10 (both doses) effectively reduced cardiac dysfunction, tau hyperphosphorylation, brain inflammation, mitochondrial dysfunction, dendritic spine loss, and improved tight junction integrity. Although both doses of NAC effectively reduced brain mitochondrial dysfunction, treatment using a high dose of NAC reduced cardiac dysfunction, brain inflammation, and dendritic spine loss. In conclusion, treatment with 2i-10 and a high dose of NAC at the onset of reperfusion alleviated brain inflammation and mitochondrial dysfunction, consequently reducing dendritic spine loss in rats with cardiac I/R injury.

Melatonin and metformin counteract cognitive dysfunction equally in male rats with doxorubicin-induced chemobrain

Melatonin (Mel) and metformin (Met) show beneficial effects in various brain pathologies. However, the effects of Mel and Met on doxorubicin (DOX)-induced chemobrain remain in need of elucidation. We aimed to investigate whether Mel and Met provide neuroprotective effects on glial dysmorphologies, brain inflammation, oxidative stress, brain mitochondrial dysfunction, apoptosis, necroptosis, neurogenesis, hippocampal dysplasticity, and cognitive dysfunction in rats with DOX-induced chemobrain. Thirty-two male Wistar rats were divided into 2 groups and received normal saline (NSS, as control, n = 8) or DOX (3 mg/kg/day; n = 24) by intraperitoneal (i.p.) injection on days 0, 4, 8, 15, 22, and 29. The DOX-treated group was divided into 3 subgroups receiving either vehicle (NSS; n = 8), Mel (10 mg/kg/day; n = 8), or Met (250 mg/kg/day; n = 8) by gavage for 30 consecutive days. Following this, cognitive function was assessed in all rats. The number of glial cells and their fluorescence intensity had decreased, while the glial morphology in DOX-treated rats showed a lower process complexity. Brain mitochondrial dysfunction, an increase in brain inflammation, oxidative stress, apoptosis and necroptosis, a decrease in the number of hippocampal dendritic spines and neurogenesis, and cognitive decline were also observed in DOX-treated rats. Mel and Met equally improved those brain pathologies, resulting in cognitive improvement in DOX-treated rats. In conclusion, concomitant treatment with either Mel or Met counteract DOX-induced chemobrain by preservation of glial morphology, brain inflammation, brain oxidative stress, brain mitochondrial function, hippocampal plasticity, and brain apoptosis. This study highlighted the role of the glia as key mediators in DOX-induced chemobrain.

PD98059 protects SH-SY5Y cells against oxidative stress in oxygen-glucose deprivation/reperfusion

Mitochondria play a key role in the cerebral ischemia-reperfusion injury. Although the extracellular signal-regulated kinase 1/2 inhibitor PD98059 (PD) is a selective and reversible flavonoid that can protect the mitochondria in a rat model of cardiac arrest/cardiopulmonary resuscitation, its role requires further confirmation. In this study, we investigated whether PD could maintain mitochondrial homeostasis and decrease reactive oxygen species (ROS) production in neuroblastoma (SH-SY5Y) cells exposed to oxygen-glucose deprivation/reperfusion (OGD/R). PD improved the mitochondrial morphology and function, reversed the increase in ROS production and cell apoptosis, and reduced total-superoxide dismutase and Mn-superoxide dismutase activities induced by OGD/R. PD decreases ROS production and improves mitochondrial morphology and function, protecting SH-SY5Y cells against OGD/R-induced injury.

Targeted Mitochondrial Drugs for Treatment of Ischemia-Reperfusion Injury

Ischemia-reperfusion injury is a complex hemodynamic pathology that is a leading cause of death worldwide and occurs in many body organs. Numerous studies have shown that mitochondria play an important role in the occurrence mechanism of ischemia-reperfusion injury and that mitochondrial structural abnormalities and dysfunction lead to the disruption of the homeostasis of the whole mitochondria. At this time, mitochondria are not just sub-organelles to produce ATP but also important targets for regulating ischemia-reperfusion injury; therefore, drugs targeting mitochondria can serve as a new strategy to treat ischemia-reperfusion injury. Based on this view, in this review, we discuss potential therapeutic agents for both mitochondrial structural abnormalities and mitochondrial dysfunction, highlighting the application and prospects of targeted mitochondrial drugs in the treatment of ischemia-reperfusion injury, and try to provide new ideas for the clinical treatment of the ischemia-reperfusion injury.

Modulation of mitochondrial dynamics rescues cognitive function in rats with 'doxorubicin-induced chemobrain' via mitigation of mitochondrial dysfunction and neuroinflammation

Doxorubicin (DOX), an effective, extensively used chemotherapeutic drug, can cause cognitive deterioration in cancer patients. The associated debilitating neurological sequelae are referred to as chemobrain. Our recent work demonstrated that Dox treatment resulted in an imbalance in mitochondrial dynamics, ultimately culminating in cognitive decline in rats. Therefore, in this study, we aim to explore the therapeutic efficacy of a pharmacological intervention, which modulates mitochondrial dynamics using a potent mitochondrial fission inhibitor (Mdivi-1) and mitochondrial fusion promoter (M1) against Dox-induced chemobrain. In the study, male Wistar rats were randomly assigned to receive either normal saline solution or six doses of Dox (3 mg·kg-1 ) via intraperitoneal injection. Then, the Dox-treated rats were intraperitoneally given either 1% DMSO as the vehicle, Mdivi-1 (1.2 mg·kg-1 ), M1 (2 mg·kg-1 ), or a combined treatment of Mdivi-1 and M1 for 30 consecutive days. Long-term learning and memory were evaluated using the novel object location task and novel object recognition task. Following euthanasia, the rat brains were dissected to enable further molecular investigation. We demonstrated that long-term treatment with mitochondrial dynamic modulators suppressed mitochondrial fission in the hippocampus following Dox treatment, leading to an improvement in brain homeostasis. Mitochondrial dynamic modulator treatments restored cognitive function in Dox-treated rats by attenuating neuroinflammation, decreasing oxidative stress, preserving synaptic integrity, reducing potential Alzheimer's related lesions, and mitigating both apoptosis and necroptosis following Dox administration. Together, our findings suggested that mitochondrial dynamics modulators protected against Dox-induced cognitive impairment by rebalancing mitochondrial homeostasis and attenuating both oxidative and inflammatory insults.

An apoptosis inhibitor suppresses microglial and astrocytic activation after cardiac ischemia/reperfusion injury

OBJECTIVE

Microglial hyperactivation and apoptosis were observed following myocardial infarction and ischemia reperfusion (I/R) injury. This study aimed to test the hypothesis that the apoptosis inhibitor, Z-VAD, attenuates microglial and astrocytic hyperactivation and brain inflammation in rats with cardiac I/R injury.

MATERIALS AND METHODS

Rats were subjected to either sham or cardiac I/R operation (30 min-ischemia followed by 120-min reperfusion), rats in the cardiac I/R group were given either normal saline solution or Z-VAD at 3.3 mg/kg via intravenous injection 15 min prior to cardiac ischemia. Left ventricular ejection fraction (% LVEF) was determined during the cardiac I/R protocol. The brain tissues were removed and used to determine brain apoptosis, brain inflammation, microglial and astrocyte morphology.

RESULTS

Cardiac dysfunction was observed in rats with cardiac I/R injury as indicated by decreased %LVEF. In the brain, we found brain apoptosis, brain inflammation, microglia hyperactivation, and reactive astrogliosis occurred following cardiac I/R injury. Pretreatment with Z-VAD effectively increased %LVEF, reduced brain apoptosis, attenuated brain inflammation by decreasing IL-1β mRNA levels, suppressed microglial and astrocytic hyperactivation and proliferation after cardiac I/R injury.

CONCLUSION

Z-VAD exerts neuroprotective effects against cardiac I/R injury not only targeting apoptosis but also microglial and astrocyte activation.

Mild cognitive impairment occurs in rats during the early remodeling phase of myocardial infarction

Cognitive impairment is a common health problem among people with heart failure (HF). Increases in oxidative stress, brain inflammation, and microglial hyperactivity have been reported in preclinical models of myocardial infarction (MI)-induced HF. We tested the hypothesis that oxidative stress, brain inflammation, mitochondrial dysfunction, and cell death participate in cognitive impairment in the early remodeling phase of MI. Rats underwent either a sham or permanent left anterior descending coronary ligation to induce MI. 1-week post-operation, MI rats with % left ventricular ejection fraction (%LVEF) ≥50 were assigned as a HF with preserved ejection fraction (HFpEF) group and MI rats with %LVEF<50 were assigned as a HF with reduced ejection fraction (HFrEF) group. Cognitive function and biochemical markers were assessed at week 5. The mean value of %LVEF in HFpEF and HFrEF were 63.62±8.33 and 42.83±3.93 respectively, which were lower than in the sham group, suggesting that these rats developed MI with cardiac dysfunction. Hippocampal dependent cognitive impairment was observed in MI rats. Serum, brain, and mitochondrial oxidative stress were all increased in MI rats, along with apoptosis, resulting in dendritic spine loss. However, brain inflammation and AD proteins did not change. In conclusion, during the early remodeling phase of MI, a high level of oxidative stress appears to be a major contributor of cellular damage which is associated with mild cognitive impairment. However, the severity of MI, as evidenced by the %LVEF, was not associated with the degree of cognitive impairment.

Pharmacological Targeting of Mitochondrial Fission and Fusion Alleviates Cognitive Impairment and Brain Pathologies in Pre-diabetic Rats

It has recently been accepted that long-term high-fat diet (HFD) intake is a significant possible cause for prediabetes and cognitive and brain dysfunction through the disruption of brain mitochondrial function and dynamic balance. Although modulation of mitochondrial dynamics by inhibiting fission and promoting fusion has been shown to reduce the morbidity and mortality associated with a variety of chronic diseases, the impact of either pharmacological inhibition of mitochondrial fission (Mdivi-1) or stimulation of fusion (M1) on brain function in HFD-induced prediabetic models has never been studied. Thirty-two male Wistar rats were separated into 2 groups and fed either a normal diet (ND, n = 8) or HFD (n = 24) for 14 weeks. At week 12, HFD-fed rats were divided into 3 subgroups (n = 8/subgroup) and given an intraperitoneal injection of either saline, Mdivi-1 (1.2 mg/kg/day), or M1 (2 mg/kg/day) for 2 weeks. Cognitive function and metabolic parameters were determined toward the end of the protocol. The rats then were euthanized, and the brain was immediately removed in order to evaluate brain mitochondrial function and mitochondrial dynamics. HFD-fed rats experienced prediabetes, evidenced by elevated plasma insulin and the HOMA index, impaired mitochondrial function in the brain, altered dynamic regulation, and cognitive impairment were also found. Mdivi-1 and M1 treatment exerted neuroprotection to a similar extent by improving metabolic parameters, balancing mitochondrial dynamics, and reducing mitochondrial dysfunction, resulting in a gradual increase in cognitive function. Therefore, pharmacological targeting of mitochondrial fission and fusion protected the brain against chronic HFD-induced prediabetes.

Myrtenol improves brain damage and promotes angiogenesis in rats with cerebral infarction by activating the ERK1/2 signalling pathway

CONTEXT

Cerebral ischaemia/reperfusion (I/R) injury has a high disability and fatality worldwide. Myrtenol has protective effects on myocardial I/R injury through antioxidant and anti-apoptotic effects.

OBJECTIVE

This study investigated the effect of myrtenol on cerebral ischaemia/reperfusion (I/R) injury and the underlying mechanism.

MATERIALS AND METHODS

Cerebral I/R injury was induced in adult Sprague-Dawley rats by middle cerebral artery occlusion (MCAO) for 90 min. MCAO rats were treated with or without myrtenol (10, 30, or 50 mg/kg/day) or/and U0126 (10 μL) intraperitoneally for 7 days.

RESULTS

In the present study, myrtenol had no toxicity at concentrations up to 1.3 g/kg. Myrtenol treatment improved neurological function of MCAO rats, with significantly (p < 0.05) improved neurological deficits (4.31 ± 1.29 vs. 0.00) and reduced brain edoema (78.95 ± 2.27% vs. 85.48 ± 1.24%). Myrtenol extenuated brain tissue injury and neuronal apoptosis, with increased Bcl-2 expression (0.48-fold) and decreased Bax expression (2.02-fold) and caspase-3 activity (1.36-fold). Myrtenol promoted angiogenesis in the brain tissues of MCAO rats, which was reflected by increased VEGF (0.86-fold) and FGF2 (0.51-fold). Myrtenol promoted the phosphorylation of MEK1/2 (0.80-fold) and ERK1/2 (0.97-fold) in MCAO rats. U0126, the inhibitor of ERK1/2 pathway, reversed the protective effects of myrtenol on brain tissue damage and angiogenesis in MCAO rats.

DISCUSSION AND CONCLUSIONS

Myrtenol reduced brain damage and angiogenesis through activating the ERK1/2 signalling pathway, which may provide a novel alternative strategy for preventing cerebral I/R injury. Further in vitro work detailing its mechanism-of-action for improving ischaemic cerebral infarction is needed.

Cell death inhibitors protect against brain damage caused by cardiac ischemia/reperfusion injury

Cognitive impairment has been reported in patients with myocardial infarction despite a successful reperfusion therapy. Several modes of cell death are involved in brain damage during cardiac ischemia/reperfusion (I/R) injury. Although apoptosis, necroptosis, and ferroptosis inhibitors provided neuroprotection against cerebral I/R injury, the effects of these cell death inhibitors on the brain following cardiac I/R injury have never been investigated. We hypothesized that apoptosis, necroptosis, and ferroptosis inhibitors attenuate brain damage following cardiac I/R injury. One-hundred and twenty-six male rats were used: 6 rats were assigned to sham operation and 120 rats were subjected to 30-min regional cardiac ischemia and 120-min reperfusion. Rats in cardiac I/R group were pretreated with either vehicle (n = 12) or one of cell death inhibitors. Rats treated with apoptosis, necroptosis, or ferroptosis inhibitor were subdivided into three different doses including low (L), medium (M), and high (H) doses (n = 12/group). Z-VAD, necrostatin-1 (Nec-1), and ferrostatin-1 (Fer-1) were used as apoptosis, necroptosis, and ferroptosis inhibitor, respectively. Rats were sacrificed at the end of reperfusion, and the brain was used to analyze dendritic spine density, Alzheimer's disease (AD)-related proteins, blood-brain barrier (BBB) tight junction proteins, mitochondrial function, inflammation, and cell death. Our data showed that cardiac I/R led to brain damage and only apoptosis occurred in the hippocampus after cardiac I/R injury. In the cardiac I/R group, treatment with M-Z-VAD and all doses of Nec-1 decreased hippocampal apoptosis and amyloid beta aggregation, thereby reducing dendritic spine loss. M- and H-Fer-1 also reduced dendritic spine loss by suppressing ACSL4, TNF-α, amyloid beta, and tau hyperphosphorylation. Moreover, Bax/Bcl-2 was decreased in all treatment regimen except L-Z-VAD. Additionally, M-Z-VAD and M-Fer-1 partially attenuated mitochondrial dysfunction. Only L-Nec-1 preserved BBB proteins. In conclusion, cell death inhibitors prevented hippocampal dendritic spine loss caused by cardiac I/R injury through different mechanisms.

Mitofusin 2, a key coordinator between mitochondrial dynamics and innate immunity

Remodeling of mitochondrial dynamics and mitochondrial morphology plays a pivotal role in the maintenance of mitochondrial homeostasis in response to pathogenic attacks or stress stimuli. In addition to their role in metabolism and energy production, mitochondria participate in diverse biological functions, including innate immune responses driven by macrophages in response to infections or inflammatory stimuli. Mitofusin-2 (MFN2), a mitochondria-shaping protein regulating mitochondrial fusion and fission, plays a crucial role in linking mitochondrial function and innate immune responses. In this article, we review the role of MFN2 in the regulation of innate immune responses during viral and bacterial infections. We also summarize the current knowledge on the role of MFN2 in coordinating inflammatory, atherogenic, and fibrotic responses. MFN2-mediated crosstalk between mitochondrial dynamics and innate immune responses may determine the outcomes of pathogenic infections.

The Role of Mitochondrial Quality Control in Cardiac Ischemia/Reperfusion Injury

A healthy mitochondrial network produces a large amount of ATP and biosynthetic intermediates to provide sufficient energy for myocardium and maintain normal cell metabolism. Mitochondria form a dynamic and interconnected network involved in various cellular metabolic signaling pathways. As mitochondria are damaged, controlling mitochondrial quantity and quality is activated by changing their morphology and tube network structure, mitophagy, and biogenesis to replenish a healthy mitochondrial network to preserve cell function. There is no doubt that mitochondrial dysfunction has become a key factor in many diseases. Ischemia/reperfusion (IR) injury is a pathological manifestation of various heart diseases. Cardiac ischemia causes temporary tissue and organelle damage. Although reperfusion is essential to compensate for nutrient deficiency, blood flow restoration inconsequently further kills the previously ischemic cardiomyocytes. To date, dysfunctional mitochondria and disturbed mitochondrial quality control have been identified as critical IR injury mechanisms. Many researchers have detected abnormal mitochondrial morphology and mitophagy, as well as aberrant levels and activity of mitochondrial biogenesis factors in the IR injury model. Although mitochondrial damage is well-known in myocardial IR injury, the causal relationship between abnormal mitochondrial quality control and IR injury has not been established. This review briefly describes the molecular mechanisms of mitochondrial quality control, summarizes our current understanding of the complex role of mitochondrial quality control in IR injury, and finally speculates on the possibility of targeted control of mitochondria and the methods available to mitigate IR injury.

Cognitive impairment in myocardial infarction and heart failure

Myocardial infarction (MI) occurs when coronary blood flow is decreased due to an obstruction/occlusion of the vessels, leading to myocardial death and progression to heart failure (HF). Cognitive impairment, anxiety, depression and memory loss are the most frequent mental health problems among patients with HF. The most common cause of cognitive decline is cardiac systolic dysfunction, which leads to reduced cerebral perfusion. Several in vivo and clinical studies provide information regarding the underlying mechanisms of HF in brain pathology. Neurohormonal activation, oxidative stress, inflammation, glial activation, dendritic spine loss and brain programmed cell death are all proposed as contributors of cognitive impairment in HF. Furthermore, several investigations into the effects of various medications on brain pathology utilizing MI models have been reported. In this review, potential mechanisms involving HF-associated cognitive impairment, as well as neuroprotective interventions in HF models, are discussed and summarized. In addition, gaps in the surrounding knowledge, including the types of brain cell death and the effects of cell death inhibitors in HF, are presented and discussed. This review provides valuable information that will suggest the potential therapeutic strategies for cognitive impairment in patients with HF.

Hyperbaric oxygen therapy restores cognitive function and hippocampal pathologies in both aging and aging-obese rats

The population of obese-elderly has increased prominently around the world. Both aging and obesity are major factors of neurodegeneration. The present study hypothesizes that HBOT attenuates metabolic disturbance, cognitive decline, hippocampal pathologies in aging and aging-obese model. Sixty Wistar rats were separated into 2 groups to receive normal-diet (ND) or high-fat diet (HFD) for 22 weeks. At week 13, ND rats were divided into two subgroups to receive vehicle (0.9 % NSS, s.c) or d-gal (150 mg/kg/d, s.c) for total 10 weeks. HFD rats were injected only d-gal (150 mg/kg/d, s.c; HFDD) for total 10 weeks. At week 20, rats in each subgroup were given sham-treatment (1ATA, 80 L/min, 80 min/day), or HBOT (2ATA, pure O₂, 250 L/min, 80 min/day) for 14 days. Novel object location test, metabolic parameters, and hippocampal pathologies were determined after HBOT. d-gal induced insulin resistance, increased oxidative stress, autophagy impairment, microglial hyperactivation, apoptosis, synaptic dysplasticity which resulted in cognitive impairment. d-gal-treated HFD-fed rats had the highest levels of oxidative stress, apoptosis, dendritic spine loss. HBOT attenuated insulin resistance, cognitive impairment, hippocampal aging and pathologies in both models. These findings suggest that HBOT restored insulin sensitivity, hippocampal functions, cognition in aging and aging-obese models.