Advances in the Study of Etiology and Molecular Mechanisms of Sensorineural Hearing Loss.

Sensorineural hearing loss (SNHL), a multifactorial progressive disorder, results from a complex interplay of genetic and environmental factors, with its underlying mechanisms remaining unclear. Several pathological factors are believed to contribute to SNHL, including genetic factors, ion homeostasis, cell apoptosis, immune inflammatory responses, oxidative stress, hormones, metabolic syndrome, human cytomegalovirus infection, mitochondrial damage, and impaired autophagy. These factors collectively interact and play significant roles in the onset and progression of SNHL. The present review offers a comprehensive overview of the various factors that contribute to SNHL, emphasizes recent developments in understanding its etiology, and explores relevant preventive and intervention measures.

Mechanistic Insights into 1,2-bis(2,4,6-tribromophenoxy)ethane-Induced Male Reproductive Toxicity in Zebrafish.

The novel brominated flame retardant, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), has increasingly been detected in environmental and biota samples. However, limited information is available regarding its toxicity, especially at environmentally relevant concentrations. In the present study, adult male zebrafish were exposed to varying concentrations of BTBPE (0, 0.01, 0.1, 1, and 10 µg/L) for 28 days. The results demonstrated underperformance in mating behavior and reproductive success of male zebrafish when paired with unexposed females. Additionally, a decline in sperm quality was confirmed in BTBPE-exposed male zebrafish, characterized by decreased total motility, decreased progressive motility, and increased morphological malformations. To elucidate the underlying mechanism, an integrated proteomic and phosphoproteomic analysis was performed, revealing a predominant impact on mitochondrial functions at the protein level and a universal response across different cellular compartments at the phosphorylation level. Ultrastructural damage, increased expression of apoptosis-inducing factor, and disordered respiratory chain confirmed the involvement of mitochondrial impairment in zebrafish testes. These findings not only provide valuable insights for future evaluations of the potential risks posed by BTBPE and similar chemicals but also underscore the need for further research into the impact of mitochondrial dysfunction on reproductive health.

Evaluation of in vitro effects of ifosfamide drug on mitochondrial functions using isolated mitochondria obtained from vital organs.

Mitochondrial toxicity has been shown to contribute to a variety of organ toxicities such as, brain, heart, kidney, and liver. Ifosfamide (IFO) as an anticancer drug, is associated with increased risk of neurotoxicity, cardiotoxicity nephrotoxicity, hepatotoxicity, and hemorrhagic cystitis. The aim of this study was to evaluate the direct effect of IFO on isolated mitochondria obtained from the rat brain, heart, kidney, and liver. Mitochondria were isolated with mechanical lysis and differential centrifugation from different organs and treated with various concentrations of IFO. Using biochemical and flowcytometry assays, we evaluated mitochondrial succinate dehydrogenase (SDH) activity, mitochondrial swelling, lipid peroxidation, reactive oxygen species (ROS) production, and mitochondrial membrane potential (MMP). Our data showed that IFO did not cause deleterious alterations in mitochondrial functions, mitochondrial swelling, lipid peroxidation ROS formation, and MMP collapse in mitochondria isolated from brain, heart, kidney, and liver. Altogether, the data showed that IFO is not directly toxic in mitochondria isolated from brain, heart, kidney, and liver. This study proved that mitochondria alone does not play the main role in the toxicity of IFO, and suggests to reduce the toxicity of this drug, other pathways resulting in the production of toxic metabolites should be considered.

A Comprehensive Review on Molecular Mechanism Involved in Arsenic Trioxide Mediated Cerebral Neurodegenerative and Infectious Diseases.

Arsenic is an environmental toxicant and its toxicity is a global health problem affecting millions of people. Arsenic exposure occurs from natural geological sources leaching into aquifers, contaminating drinking water and may also occur from mining and other industrial processes. Both cancerous, noncancerous and immunological complications are possible after arsenic exposure. The many other target organs like lungs, thymus, spleen, liver, heart, kidney, and brain. Arsenic-mediated neuro, as well as immunotoxicity, is the main concern of this review. Long-term arsenic exposure can lead to various neurological dysfunctions, which may cause neurobehavioral defects and biochemical impairment in the brain, this might negatively affect one's quality of life in later stages. Arsenic also alters the levels of various neurotransmitters such as serotonin, dopamine and norepinephrine in the brain which produces neurotoxic effects and immunological deficiency. So, it is crucial to understand the neurotoxic mechanism of arsenic trioxide-mediated cerebro neurodegenerative and immunerelated alterations. One of the major mechanisms by which it exerts its toxic effect is through an impairment of cellular respiration by inhibition of various mitochondrial enzymes, and the uncoupling of oxidative phosphorylation. This review focuses on the various toxic mechanisms responsible for arsenic-mediated neurobehavioral and immune-related changes. Therefore, this review provides a critical analysis of mitochondrial dysfunctions, oxidative stress, glutamate excitatory, inflammatory and apoptosis-related mechanistic aspects in arsenic-mediated immunotoxicity, neurotoxicity, and neurodegenerative changes.

TRPA1 promotes cisplatin-induced acute kidney injury via regulating the endoplasmic reticulum stress-mitochondrial damage.

BACKGROUND: Cisplatin is a widely used and effective chemotherapeutic agent against cancer. However, nephrotoxicity is one of the most common side effects of cisplatin, and it can proceed to acute kidney injury (AKI). Studies have reported that activation of transient receptor potential ankyrin-1 (TRPA1) mediates cisplatin-induced renal tubular cytotoxic injury. The aim of this study was to investigate the mechanism of TRPA1 in promoting cisplatin-induced AKI through modulation of the endoplasmic reticulum stress (ERS)-mitochondrial damage. METHODS: A cisplatin-induced HK-2 cell model in vitro and mouse model in vivo were established. The mechanism of TRPA1 promotes AKI was elucidated by H&E staining, TUNEL staining, transmission electron microscope (TEM), immunofluorescence, CCK-8 viability assays, flow cytometry, Western blotting, JC-1 assay, and enzyme linked immunosorbent assay (ELISA). RESULT: In vivo and in vitro, HC-030031 reduced cisplatin-induced Scr and BUN level elevations; improved cisplatin-induced renal tissue injury, apoptosis, and mitochondrial dysfunction; elevated the reduced ERS-associated proteins glucose-regulated protein 78 (GRP78), glucose-regulated protein 75 (GRP75), and C/EBP homologous protein (CHOP) levels induced by cisplatin; reduced the elevated optic atrophy 1 (OPA1), mito-fusion 1 (MFN1), and mito-fusion 2 (MFN2) protein levels, and elevated phospho-dynamin-related protein 1 (p-DRP1) and mitochondrial fission factor (MFF) protein levels. HC-030031 also reduced the mitochondria-associated endoplasmic reticulum membrane (MAM) structure. In addition, TRPA1 agonists also decreased cell proliferation, increased apoptosis, and triggered mitochondrial dysfunction and calcium overload in HK-2 cells via modulation of MAM. ERS inhibitors and GRP75 inhibitors reversed these changes caused by TRPA1 agonists. CONCLUSION: Our findings suggest that TRPA1 enhances cisplatin-induced AKI via modulation of ERS and mitochondrial damage.

Co-occurrence of Mycotoxin-Induced Hepatotoxicity in Mice Inhibited by Lycopene: Mitochondrial Impairment and Early Hepatic Fibrosis.

SCOPE: Mycotoxins co-contamination of agricultural products poses a serious threat to human and animal health, especially hepatic dysfunction. Zearalenone (ZEN), deoxynivalenol (DON), and aflatoxin B1 (AFB1) are three commonly co-occurring mycotoxins. This study is to determine whether lycopene (LYC) can alleviate hepatic toxicity induced by the co-occurrence of ZEN, DON, and AFB1 in mice. METHODS AND RESULTS: Eighty 6-week-old male ICR mice are divided into four groups: CON group (solvent control), LYC group (10 mg kg-1 LYC), Co-M group (10 mg kg-1 ZEN + 1 mg kg-1 DON + 0.5 mg kg-1 AFB1), and LYC+Co-M group (10 mg kg-1 LYC + 10 mg kg-1 ZEN + 1 mg kg-1 DON + 0.5 mg kg-1 AFB1). The results show that LYC can suppress the co-occurrence of mycotoxin-induced mitochondrial swelling and vacuolization accompanied by dysregulation of indices of mitochondrial dynamics (Mitofusin 1 (Mfn1), Mfn2, Optic atrophy 1 (Opa1), Dynamin-related protein 1 (Drp1), Fission 1 (Fis1) at the mRNA level; DRP1 and FIS1 at the protein level). LYC effectively inhibits co-occurrence of mycotoxin-induced activation of Cytochrome P450 2E1, and early fibrosis, as determined by staining with Masson's trichrome and α-SMA protein. CONCLUSION: LYC successfully attenuates early hepatic fibrosis mainly through antioxidant activities and prevented mitochondrial injury.

Neuroprotective effects of the PPARß/δ antagonist GSK0660 in in vitro and in vivo Parkinson's disease models.

BACKGROUND: The underlying mechanism of Parkinson's disease are still unidentified, but excitotoxicity, oxidative stress, and neuroinflammation are considered key actors. Proliferator activated receptors (PPARs) are transcription factors involved in the control of numerous pathways. Specifically, PPARß/δ is recognized as an oxidative stress sensor, and we have previously reported that it plays a detrimental role in neurodegeneration. METHODS: Basing on this concept, in this work, we tested the potential effects of a specific PPARß/δ antagonist (GSK0660) in an in vitro model of Parkinson's disease. Specifically, live-cell imaging, gene expression, Western blot, proteasome analyses, mitochondrial and bioenergetic studies were performed. Since we obtained promising results, we tested this antagonist in a 6-hydroxydopamine hemilesioned mouse model. In the animal model, behavioral tests, histological analysis, immunofluorescence and western blot of substantia nigra and striatum upon GSK0660 were assayed. RESULTS: Our findings suggested that PPARß/δ antagonist has neuroprotective potential due to neurotrophic support, anti-apoptotic and anti-oxidative effects paralleled to an amelioration of mitochondria and proteasome activity. These findings are strongly supported also by the siRNA results demonstrating that by silencing PPARß/δ a significative rescue of the dopaminergic neurons was obtained, thus indicating an involvement of PPARß/δ in PD's pathogenesis. Interestingly, in the animal model, GSK0660 treatment confirmed neuroprotective effects observed in the in vitro studies. Neuroprotective effects were highlighted by the behavioural performance and apomorphine rotation tests amelioration and the reduction of dopaminergic neuronal loss. These data were also confirmed by imaging and western blotting, indeed, the tested compound decreased astrogliosis and activated microglia, concomitant with an upregulation of neuroprotective pathways. CONCLUSIONS: In summary, PPARß/δ antagonist displayed neuroprotective activities against 6-hydroxydopamine detrimental effects both in vitro and in vivo models of Parkinson's disease, suggesting that it may represent a novel therapeutic approach for this disorder.

Evaluation of the cytotoxic activity of triphenyl phosphate on mouse spermatocytes cells.

Triphenyl phosphate (TPhP) is one of the most commonly found organophosphorus flame retardants (OPFRs) in the environment and the general population. Continuous daily exposure to TPhP may adversely impact male reproductive health. However, few researches were conducted to investigate the direct effects of TPhP on the progress of sperm growth and development. In this study, mouse spermatocyte GC-2spd (GC-2) cells were selected as an in vitro model, the impact of oxidative stress, mitochondrial impairment, DNA damage, cell apoptosis and the related molecular mechanisms were investigated using high content screening (HCS) system. Our study indicated that cell viability was decreased significantly in a dose-dependent manner after TPhP treatment with the half lethal concentration (LC50) at 105.8, 61.61 and 53.23 µM for 24, 48 and 72 h. A concentration-related apoptosis occurrence was observed in GC-2 cells after TPhP exposure for 48 h. In addition, the elevated intracellular reactive oxygen species (ROS) and the total antioxidant capacity (T-AOC) also observed after exposing to 6, 30 and 60 µM of TPhP. Furthermore, based on the enhancement of pH2AX protein and alteration of nuclear morphology or DNA content, DNA damage might be induced by higher concentration of TPhP treatment. Simultaneously, alteration of mitochondrial structure, enhancement of mitochondrial membrane potential (MMP), reduction of cellular adenosine triphosphate (ATP) content, altered expression of Bcl-2 family proteins, release of cytochrome c and increase of caspase-3 and caspase-9 activity demonstrated that caspase-3 dependent mitochondrial pathway might play a key role in the process of GC-2 cell apoptosis. Taken together, these results showed that TPhP was a mitochondrial toxicant and apoptotic inducer, which might trigger alike responses in human spermatogenic cells. Therefore, the potential reproductive toxicity of TPhP should not be ignored.

Mitochondrial impairment and downregulation of Drp1 phosphorylation underlie the antiproliferative and proapoptotic effects of alantolactone on oral squamous cell carcinoma cells.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is one of the most prevalent and fatal oral cancers. Mitochondria-targeting therapies represent promising strategies against various cancers, but their applications in treating OSCC are limited. Alantolactone (ALT) possesses anticancer properties and also regulates mitochondrial events. In this study, we explored the effects of ALT on OSCC and the related mechanisms. METHODS: The OSCC cells were treated with varying concentrations and duration of ALT and N-Acetyl-L-cysteine (NAC). The cell viability and colony formation were assessed. The apoptotic rate was evaluated by flow cytometry with Annexin V-FITC/PI double staining. We used DCFH-DA and flow cytometry to detect reactive oxygen species (ROS) production and DAF-FM DA to investigate reactive nitrogen species (RNS) level. Mitochondrial function was reflected by mitochondrial reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and ATP levels. KEGG enrichment analyses determined the mitochondrial-related hub genes involved in OSCC progression. Dynamin-related protein 1 (Drp1) overexpression plasmids were further transfected into the cells to analyze the role of Drp1 in OSCC progression. Immunohistochemistry staining and western blot verified the expression of the protein. RESULTS: ALT exerted anti-proliferative and pro-apoptosis effects on OSCC cells. Mechanistically, ALT elicited cell injury by promoting ROS production, mitochondrial membrane depolarization, and ATP depletion, which were reversed by NAC. Bioinformatics analysis showed that Drp1 played a crucial role in OSCC progression. OSCC patients with low Drp1 expression had a higher survival rate. The OSCC cancer tissues presented higher phosphorylated-Drp1 and Drp1 levels than the normal tissues. The results further showed that ALT suppressed Drp1 phosphorylation in OSCC cells. Moreover, Drp1 overexpression abolished the reduced Drp1 phosphorylation by ALT and promoted the cell viability of ALT-treated cells. Drp1 overexpression also reversed the mitochondrial dysfunction induced by ALT, with decreased ROS production, and increased mitochondrial membrane potential and ATP level. CONCLUSIONS: ALT inhibited proliferation and promoted apoptosis of oral squamous cell carcinoma cells via impairment of mitochondrial homeostasis and regulation of Drp1. The results provide a solid basis for ALT as a therapeutic candidate for treating OSCC, with Drp1 being a novel therapeutic target in treating OSCC.

Mitochondrial calcium uptake 3 mitigates cerebral amyloid angiopathy-related neuronal death and glial inflammation by reducing mitochondrial dysfunction.

Cerebral amyloid angiopathy (CAA) is characterized by the cerebrovascular amyloid-ß (Aß) accumulation, and always accompanied by Alzheimer's disease (AD). Mitochondrial dysfunction-associated cellular events including cell death, inflammation and oxidative stress are implicated in the progression of CAA. Unfortunately, the molecular mechanisms revealing CAA pathogenesis are still obscure, thus requiring further studies. Mitochondrial calcium uptake 3 (MICU3), a regulator of the mitochondrial Ca2+ uniporter (MCU), mediates various biological functions, but its expression and influence on CAA are largely unknown. In the present study, we found that MICU3 expression was gradually declined in cortex and hippocampus of Tg-SwDI transgenic mice. Using stereotaxic operation with AAV9 encoding MICU3, we showed that AAV-MICU3 improved the behavioral performances and cerebral blood flow (CBF) in Tg-SwDI mice, along with markedly reduced Aß deposition through mediating Aß metabolism process. Importantly, we found that AAV-MICU3 remarkably improved neuronal death and mitigated glial activation and neuroinflammation in cortex and hippocampus of Tg-SwDI mice. Furthermore, excessive oxidative stress, mitochondrial impairment and dysfunction, decreased ATP and mitochondrial DNA (mtDNA) were detected in Tg-SwDI mice, while being considerably ameliorated upon MICU3 over-expression. More importantly, our in vitro experiments suggested that MICU3-attenuated neuronal death, activation of glial cells and oxidative stress were completely abrogated upon PTEN induced putative kinase 1 (PINK1) knockdown, indicating that PINK1 was required for MICU3 to perform its protective effects against CAA. Mechanistic experiment confirmed an interaction between MICU3 and PINK1. Together, these findings demonstrated that MICU3-PINK1 axis may serve as a key target for CAA treatment mainly through improving mitochondrial dysfunction.

Short communication: unique metabolic signature of proliferative retinopathy in the tear fluid of diabetic patients with comorbidities - preliminary data for PPPM validation.

Type 2 diabetes (T2DM) defined as the adult-onset type that is primarily not insulin-dependent, comprises over 95% of all diabetes mellitus (DM) cases. According to global records, 537 million adults aged 20-79 years are affected by DM that means at least 1 out of 15 persons. This number is projected to grow by 51% by the year 2045. One of the most common complications of T2DM is diabetic retinopathy (DR) with an overall prevalence over 30%. The total number of the DR-related visual impairments is on the rise, due to the growing T2DM population. Proliferative diabetic retinopathy (PDR) is the progressing DR and leading cause of preventable blindness in working-age adults. Moreover, PDR with characteristic systemic attributes including mitochondrial impairment, increased cell death and chronic inflammation, is an independent predictor of the cascading DM-complications such as ischemic stroke. Therefore, early DR is a reliable predictor appearing upstream of this "domino effect". Global screening, leading to timely identification of DM-related complications, is insufficiently implemented by currently applied reactive medicine. A personalised predictive approach and cost-effective targeted prevention shortly - predictive, preventive and personalised medicine (PPPM / 3PM) could make a good use of the accumulated knowledge, preventing blindness and other severe DM complications. In order to reach this goal, reliable stage- and disease-specific biomarker panels are needed characterised by an easy way of the sample collection, high sensitivity and specificity of analyses. In the current study, we tested the hypothesis that non-invasively collected tear fluid is a robust source for the analysis of ocular and systemic (DM-related complications) biomarker patterns suitable for differential diagnosis of stable DR versus PDR. Here, we report the first results of the comprehensive ongoing study, in which we correlate individualised patient profiles (healthy controls versus patients with stable D as well as patients with PDR with and without co-morbidities) with their metabolic profiles in the tear fluid. Comparative mass spectrometric analysis performed has identified following metabolic clusters which are differentially expressed in the groups of comparison: acylcarnitines, amino acid & related compounds, bile acids, ceramides, lysophosphatidyl-choline, nucleobases & related compounds, phosphatidyl-cholines, triglycerides, cholesterol esters, and fatty acids. Our preliminary data strongly support potential clinical utility of metabolic patterns in the tear fluid indicating a unique metabolic signature characteristic for the DR stages and PDR progression. This pilot study creates a platform for validating the tear fluid biomarker patterns to stratify T2DM-patients predisposed to the PDR. Moreover, since PDR is an independent predictor of severe T2DM-related complications such as ischemic stroke, our international project aims to create an analytical prototype for the "diagnostic tree" (yes/no) applicable to healthrisk assessment in diabetes care.

NLRP3 Inflammasome-Mediated Neuroinflammation and Related Mitochondrial Impairment in Parkinson's Disease.

Parkinson's disease (PD) is a common neurodegenerative disorder caused by the loss of dopamine neurons in the substantia nigra and the formation of Lewy bodies, which are mainly composed of alpha-synuclein fibrils. Alpha-synuclein plays a vital role in the neuroinflammation mediated by the nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome in PD. A better understanding of the NLRP3 inflammasome-mediated neuroinflammation and the related mitochondrial impairment during PD progression may facilitate the development of promising therapies for PD. This review focuses on the molecular mechanisms underlying NLRP3 inflammasome activation, comprising priming and protein complex assembly, as well as the role of mitochondrial impairment and its subsequent inflammatory effects on the progression of neurodegeneration in PD. In addition, the therapeutic strategies targeting the NLRP3 inflammasome for PD treatment are discussed, including the inhibitors of NLRP3 inflammatory pathways, mitochondria-focused treatments, microRNAs, and other therapeutic compounds.

Targeting mitochondrial impairment for the treatment of cardiovascular diseases: From hypertension to ischemia-reperfusion injury, searching for new pharmacological targets.

Mitochondria and mitochondrial proteins represent a group of promising pharmacological target candidates in the search of new molecular targets and drugs to counteract the onset of hypertension and more in general cardiovascular diseases (CVDs). Indeed, several mitochondrial pathways result impaired in CVDs, showing ATP depletion and ROS production as common traits of cardiac tissue degeneration. Thus, targeting mitochondrial dysfunction in cardiomyocytes can represent a successful strategy to prevent heart failure. In this context, the identification of new pharmacological targets among mitochondrial proteins paves the way for the design of new selective drugs. Thanks to the advances in omics approaches, to a greater availability of mitochondrial crystallized protein structures and to the development of new computational approaches for protein 3D-modelling and drug design, it is now possible to investigate in detail impaired mitochondrial pathways in CVDs. Furthermore, it is possible to design new powerful drugs able to hit the selected pharmacological targets in a highly selective way to rescue mitochondrial dysfunction and prevent cardiac tissue degeneration. The role of mitochondrial dysfunction in the onset of CVDs appears increasingly evident, as reflected by the impairment of proteins involved in lipid peroxidation, mitochondrial dynamics, respiratory chain complexes, and membrane polarization maintenance in CVD patients. Conversely, little is known about proteins responsible for the cross-talk between mitochondria and cytoplasm in cardiomyocytes. Mitochondrial transporters of the SLC25A family, in particular, are responsible for the translocation of nucleotides (e.g., ATP), amino acids (e.g., aspartate, glutamate, ornithine), organic acids (e.g. malate and 2-oxoglutarate), and other cofactors (e.g., inorganic phosphate, NAD+, FAD, carnitine, CoA derivatives) between the mitochondrial and cytosolic compartments. Thus, mitochondrial transporters play a key role in the mitochondria-cytosol cross-talk by leading metabolic pathways such as the malate/aspartate shuttle, the carnitine shuttle, the ATP export from mitochondria, and the regulation of permeability transition pore opening. Since all these pathways are crucial for maintaining healthy cardiomyocytes, mitochondrial carriers emerge as an interesting class of new possible pharmacological targets for CVD treatments.

Taurine Improves Sperm Mitochondrial Indices, Blunts Oxidative Stress Parameters, and Enhances Steroidogenesis and Kinematics of Sperm in Lead-Exposed Mice.

Lead (Pb) is a highly toxic heavy metal. Pb exposure could adversely affect many organs, including the male reproductive system. Oxidative stress and mitochondrial impairment play a fundamental role in the pathogenesis of Pb-induced male reproductive system injury. Taurine (TAU) is abundantly found in mammalian bodies. The positive effects of TAU on oxidative stress biomarkers and mitochondrial function have been reported. The current study evaluated the effects of TAU on Pb-induced reproductive toxicity. Mice received Pb (20 mg/kg/day; gavage, 35 consecutive days). Then, sperm indices (quality and quantity) together with sperm kinetics, sperm mitochondrial parameters, testicular and sperm oxidative stress biomarkers, testis and plasma testosterone levels, and the expression of genes involved in the steroidogenesis process have been evaluated. Pb caused significant histopathological alterations and oxidative stress in male mice's reproductive system and sperm. Moreover, significant mitochondrial function impairment was evident in sperm isolated from Pb-treated mice. Pb exposure also suppressed the expression of StAR, 17ß-HSD, CYP11A, and 3ß-HSD genes in the male gonad. It was found that TAU (500 and 1000 mg/kg) significantly improved oxidative stress biomarkers in both male gonads and gametes of Pb-treated mice. TAU also significantly restored sperm mitochondrial function and kinetics. The expression of genes involved in steroidogenesis was also higher in TAU-treated animals. These data suggest TAU as an effective agent against Pb-induced reproductive toxicity. The effects of TAU on oxidative stress markers, mitochondrial function, and the steroidogenesis process seem to play a fundamental role in its protective properties. Further studies are warranted to detect the precise protective effects of this amino acid in the reproductive system. Lead (Pb) is a toxic element that adversely affects the male reproductive system. Mitochondrial impairment and oxidative stress have a crucial role in the Pb-induced reproductive toxicity. Taurine (TAU) could considerably improve the reproductive toxicity induced by Pb via enhancing mitochondrial function and mitigating oxidative stress indices. ΔΨ, mitochondrial membrane potential; ATP, adenosine triphosphate.

Cyclophilin D-induced mitochondrial impairment confers axonal injury after intracerebral hemorrhage in mice.

The mitochondrial permeability transition pore is a nonspecific transmembrane channel. Inhibition of mitochondrial permeability transition pore opening has been shown to alleviate mitochondrial swelling, calcium overload, and axonal degeneration. Cyclophilin D is an important component of the mitochondrial permeability transition pore. Whether cyclophilin D participates in mitochondrial impairment and axonal injury after intracerebral hemorrhage is not clear. In this study, we established mouse models of intracerebral hemorrhage in vivo by injection of autologous blood and oxyhemoglobin into the striatum in Thy1-YFP mice, in which pyramidal neurons and axons express yellow fluorescent protein. We also simulated intracerebral hemorrhage in vitro in PC12 cells using oxyhemoglobin. We found that axonal degeneration in the early stage of intracerebral hemorrhage depended on mitochondrial swelling induced by cyclophilin D activation and mitochondrial permeability transition pore opening. We further investigated the mechanism underlying the role of cyclophilin D in mouse models and PC12 cell models of intracerebral hemorrhage. We found that both cyclosporin A inhibition and short hairpin RNA interference of cyclophilin D reduced mitochondrial permeability transition pore opening and mitochondrial injury. In addition, inhibition of cyclophilin D and mitochondrial permeability transition pore opening protected corticospinal tract integrity and alleviated motor dysfunction caused by intracerebral hemorrhage. Our findings suggest that cyclophilin D is used as a key mediator of axonal degeneration after intracerebral hemorrhage; inhibition of cyclophilin D expression can protect mitochondrial structure and function and further alleviate corticospinal tract injury and motor dysfunction after intracerebral hemorrhage. Our findings provide a therapeutic target for preventing axonal degeneration of white matter injury and subsequent functional impairment in central nervous diseases.

NLRP3 Inflammasome-Mediated Neuroinflammation and Related Mitochondrial Impairment in Parkinson's Disease / 神经科学通报·英文版

Parkinson's disease (PD) is a common neurodegenerative disorder caused by the loss of dopamine neurons in the substantia nigra and the formation of Lewy bodies, which are mainly composed of alpha-synuclein fibrils. Alpha-synuclein plays a vital role in the neuroinflammation mediated by the nucleotide-binding oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome in PD. A better understanding of the NLRP3 inflammasome-mediated neuroinflammation and the related mitochondrial impairment during PD progression may facilitate the development of promising therapies for PD. This review focuses on the molecular mechanisms underlying NLRP3 inflammasome activation, comprising priming and protein complex assembly, as well as the role of mitochondrial impairment and its subsequent inflammatory effects on the progression of neurodegeneration in PD. In addition, the therapeutic strategies targeting the NLRP3 inflammasome for PD treatment are discussed, including the inhibitors of NLRP3 inflammatory pathways, mitochondria-focused treatments, microRNAs, and other therapeutic compounds.

Neuroprotective effects of the PPARß/δ antagonist GSK0660 in in vitro and in vivo Parkinson's disease models

BACKGROUND: The underlying mechanism of Parkinson's disease are still unidentified, but excitotoxicity, oxidative stress, and neuroinflammation are considered key actors. Proliferator activated receptors (PPARs) are transcription factors involved in the control of numerous pathways. Specifically, PPARß/δ is recognized as an oxidative stress sensor, and we have previously reported that it plays a detrimental role in neurodegeneration. METHODS: Basing on this concept, in this work, we tested the potential effects of a specific PPARß/δ antagonist (GSK0660) in an in vitro model of Parkinson's disease. Specifically, live-cell imaging, gene expression, Western blot, proteasome analyses, mitochondrial and bioenergetic studies were performed. Since we obtained promising results, we tested this antagonist in a 6-hydroxydopamine hemilesioned mouse model. In the animal model, behavioral tests, histological analysis, immunofluorescence and western blot of substantia nigra and striatum upon GSK0660 were assayed. RESULTS: Our findings suggested that PPARß/δ antagonist has neuroprotective potential due to neurotrophic support, anti-apoptotic and anti-oxidative effects paralleled to an amelioration of mitochondria and proteasome activity. These findings are strongly supported also by the siRNA results demonstrating that by silencing PPARß/δ a significative rescue of the dopaminergic neurons was obtained, thus indicating an involvement of PPARß/δ in PD's pathogenesis. Interestingly, in the animal model, GSK0660 treatment confirmed neuroprotective effects observed in the in vitro studies. Neuroprotective effects were highlighted by the behavioural performance and apomorphine rotation tests amelioration and the reduction of dopaminergic neuronal loss. These data were also confirmed by imaging and western blotting, indeed, the tested compound decreased astrogliosis and activated microglia, concomitant with an upregulation of neuroprotective pathways. CONCLUSIONS: In summary, PPARß/δ antagonist displayed neuroprotective activities against 6-hydroxydopamine detrimental effects both in vitro and in vivo models of Parkinson's disease, suggesting that it may represent a novel therapeutic approach for this disorder.

Mitochondrial Damage of Lymphocytes in Patients with Acute Relapse of Schizophrenia: A Correlational Study with Efficacy and Clinical Symptoms.

Objective: Accumulating evidence has demonstrated that schizophrenia is associated with mitochondrial and immune abnormalities. In this pilot case-control study, we investigated the level of mitochondrial impairment in lymphocytes in patients with acute relapse of schizophrenia and explored the correlation between the level of mitochondrial damage and symptoms or treatment response. Methods: Lymphocytic mitochondrial damage was detected using mitochondrial fluorescence staining and flow cytometry in 37 patients (at admission and discharge) and 24 controls. Clinical symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression Scale (CGI-S). Results: The levels of mitochondrial damage in CD3+ T, CD4+ T, and CD8+ T lymphocytes of the patients with schizophrenia at admission were significantly higher than those of the controls (p<0.05) and did not return to normal at discharge (p>0.05). The mitochondrial damage of T cells significantly improved at discharge for responsive patients only, as compared with that at admission (P<0.05). However, no significant difference was found in mitochondrial damage in CD19+ B cells between patients and healthy controls, or between admission and discharge (p>0.05). Furthermore, the reduction in mitochondrial damage of CD3, CD4, and CD8 lymphocytes was positively correlated with the reduction of the score of the PANSS positive scale at discharge (p<0.05), while no significant correlation was found between the level of mitochondrial damage in lymphocytes and the scores of PANSS and CGI-S. Conclusion: Acute relapse of schizophrenia might be associated with higher levels of mitochondrial damage in peripheral blood T lymphocytes. The degree of recovery of mitochondrial impairment in the T cells may be used as a predictor of treatment response in schizophrenia. As this is a pilot study, the conclusion still needs further verification in large-scale studies.

Chlorinated organophosphorus flame retardants-induced mitochondrial abnormalities and the correlation with progesterone production in mLTC-1 cells.

Environmental monitoring data have indicated that three chlorinated organophosphorus flame retardants (Cl-OPFRs), including tris(2-chloroethyl)-phosphate (TCEP), tris(2-chloropropyl)-phosphate (TCPP), and tris(1,3-dichloro-2-propyl)-phosphate (TDCPP) are the predominant chemicals in various environmental matrices and exhibit reproductive endocrine disrupting activities. Currently, mitochondrial abnormality is a new paradigm for evaluating chemical-mediated cell dysfunction. However, a comprehensive correlation between these two aspects of Cl-OPFRs remains unclear. In this research, the effects of TCEP, TCPP, and TDCPP on progesterone production and mitochondrial impairment were investigated by using mouse Leydig tumor cells (mLTC-1). The half maximal inhibitory concentration (IC50) values at 48 h exposure indicated that the rank order of anti-androgenic activity was TDCPP > TCPP. Whereas, TCEP exhibited elevation of progesterone production. At concentrations close to IC50 of progesterone production by TCPP and TDCPP, the elevation of intracellular reactive oxygen species (ROS), depletion of mitochondrial membrane potential (MMP), reduction of cellular adenosine triphosphate (ATP) content, and alteration of mitochondrial structures was observed. In addition, the expression of main genes related to progesterone synthesis was dramatically down-regulated by TCPP and TDCPP treatments. These results imply that the inhibition effect of TCPP and TDCPP on progesterone production might be related to mitochondrial damage and down-regulated steroidogenic genes.

Glycine protects the male reproductive system against lead toxicity via alleviating oxidative stress, preventing sperm mitochondrial impairment, improving kinematics of sperm, and blunting the downregulation of enzymes involved in the steroidogenesis.

Lead (Pb) is a highly toxic heavy metal widely dispersed in the environment because of human industrial activities. Many studies revealed that Pb could adversely affect several organs, including the male reproductive system. Pb-induced reproductive toxicity could lead to infertility. Thus, finding safe and clinically applicable protective agents against this complication is important. It has been found that oxidative stress plays a fundamental role in the pathogenesis of Pb-induced reprotoxicity. Glycine is the simplest amino acid with a wide range of pharmacological activities. It has been found that glycine could attenuate oxidative stress and mitochondrial impairment in various experimental models. The current study was designed to evaluate the role of glycine in Pb-induced reproductive toxicity in male mice. Male BALB/c mice received Pb (20 mg/kg/day; gavage; 35 consecutive days) and treated with glycine (250 and 500 mg/kg/day; gavage; 35 consecutive days). Then, reproductive system weight indices, biomarkers of oxidative stress in the testis and isolated sperm, sperm kinetic, sperm mitochondrial indices, and testis histopathological alterations were monitored. A significant change in testis, epididymis, and Vas deferens weight was evident in Pb-treated animals. Markers of oxidative stress were also significantly increased in the testis and isolated sperm of the Pb-treated group. A significant disruption in sperm kinetic was also evident when mice received Pb. Moreover, Pb exposure caused significant deterioration in sperm mitochondrial indices. Tubular injury, tubular desquamation, and decreased spermatogenic index were histopathological alterations detected in Pb-treated mice. It was found that glycine significantly blunted oxidative stress markers in testis and sperm, improved sperm mitochondrial parameters, causing considerable higher velocity-related indices (VSL, VCL, and VAP) and percentages of progressively motile sperm, and decreased testis histopathological changes in Pb-exposed animals. These data suggest glycine as a potential protective agent against Pb-induced reproductive toxicity. The effects of glycine on oxidative stress markers and mitochondrial function play a key role in its protective mechanism.