Mitochondria and programmed cell death: back to the future

Advances in pathogenesis and treatment of vascular endothelial injury-related diseases mediated by mitochondrial abnormality

Vascular endothelial cells, serving as a barrier between blood and the arterial wall, play a crucial role in the early stages of the development of atherosclerosis, cardiovascular diseases (CVDs), and Alzheimer's disease (AD). Mitochondria, known as the powerhouses of the cell, are not only involved in energy production but also regulate key biological processes in vascular endothelial cells, including redox signaling, cellular aging, calcium homeostasis, angiogenesis, apoptosis, and inflammatory responses. The mitochondrial quality control (MQC) system is essential for maintaining mitochondrial homeostasis. Current research indicates that mitochondrial dysfunction is a significant driver of endothelial injury and CVDs. This article provides a comprehensive overview of the causes of endothelial injury in CVDs, ischemic stroke in cerebrovascular diseases, and AD, elucidating the roles and mechanisms of mitochondria in these conditions, and aims to develop more effective therapeutic strategies. Additionally, the article offers treatment strategies for cardiovascular and cerebrovascular diseases, including the use of clinical drugs, antioxidants, stem cell therapy, and specific polyphenols, providing new insights and methods for the clinical diagnosis and treatment of related vascular injuries to improve patient prognosis and quality of life. Future research should delve deeper into the molecular and mechanistic links between mitochondrial abnormalities and endothelial injury, and explore how to regulate mitochondrial function to prevent and treat CVDs.

Development of Cu(II) 4-hydroxybenzoylhydrazone complexes that induce mitochondrial DNA damage and mitochondria-mediated apoptosis in liver cancer

Cisplatin remains the most widely used chemotherapeutic agent in cancer treatment; however, its inherent drawbacks have fueled the development of novel metalloanticancer drugs. In this study, two novel Cu(II) complexes (Cu1 and Cu2) were designed and synthesized. Notably, these Cu(II) complexes showed higher cytotoxicity against HL-7402 cells than cisplatin. Moreover, Cu(II) complexes significantly inhibited liver cancer growth in a xenograft model. A mechanism study revealed that the Cu(II) complexes reduced the mitochondrial membrane potential of cancer cells, produced excessive reactive oxygen species (ROS), induced mitochondrial DNA (mtDNA) damage, and ultimately facilitated cancer cell apoptosis.

Construction of 5-Fluorouracil and Gallium Corrole Conjugates for Enhanced Photodynamic Therapy

Molecular hybridization is a well-established strategy for developing new drugs. In the pursuit of promising photosensitizers (PSs) with enhanced photodynamic therapy (PDT) efficiency, a series of novel 5-fluorouracil (5FU) gallium corrole conjugates (1-Ga-4-Ga) were designed and synthesized by hybridizing a chemotherapeutic drug and PSs. Their photodynamic antitumor activity was also evaluated. The most active complex (2-Ga) possesses a low IC50 value of 0.185 μM and a phototoxic index of 541 against HepG2 cells. Additionally, the 5FU-gallium corrole conjugate (2-Ga) exhibited a synergistic increase in cytotoxicity under irradiation. Excitedly, treatment of HepG2 tumor-bearing mice with 2-Ga under irradiation could completely ablate tumors without harming normal tissues. 2-Ga-mediated PDT could disrupt mitochondrial function, cause cell cycle arrest in the sub-G1 phase, and activate the cell apoptosis pathway by upregulating the cleaved PARP expression and the Bax/Bcl-2 ratios. This work provides a useful strategy for the design of new corrole-based chemo-photodynamic therapy drugs.

A novel neuroprotective peptide YVYAETY identified and screened from Flammulina velutipes protein hydrolysates attenuates scopolamine-induced cognitive impairment in mice

Flammulina velutipes protein hydrolysates are known for their abundant amino acids and excellent developmental values. This study aimed to identify and screen neuroprotective peptides from F. velutipes protein hydrolysates in vitro and validate the protective effects of YVYAETY on memory impairment in scopolamine-induced mice. The F. velutipes protein was hydrolyzed by simulated gastrointestinal digestion, followed by purification through ultrafiltration and gel chromatography. The fraction exhibiting the strongest neuroprotective activity was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The main identified peptides (SDLKPADF, WNDHYY, YVYAETY, and WFHPLF) effectively mitigated excessive ROS production by increasing SOD and GSH-px activities while inhibiting cell apoptosis and mitochondrial membrane potential (MMP) collapse against oxidative stress in Aβ25-35-induced HT22 cells. By molecular docking, the interaction between peptides and the active site of the Keap1-Kelch domain reveals their capacity to regulate the Keap1/Nrf2/HO-1 pathway. In vitro, the peptide YVYAETY had the best effect and can be further validated in vivo. The behavioral tests showed that YVYAETY improved scopolamine-induced cognitive impairment in mice. YVYAETY also alleviated neuron damage including neuron vacuolation and pyknotic nuclei in the hippocampus. Furthermore, it significantly inhibited oxidative stress and suppressed the activation of the Nrf2 pathway. Therefore, this study revealed that YVYAETY had the potential to serve as a novel neuroprotective agent.

AM-18002, a derivative of natural anmindenol A, enhances radiosensitivity in mouse breast cancer cells

Natural anmindenol A isolated from the marine-derived bacteria Streptomyces sp. caused potent inhibition of inducible nitric oxide synthase without any significant cytotoxicity. This compound consists of a structurally unique 3,10-dialkylbenzofulvene skeleton. We previously synthesized and screened the novel derivatives of anmindenol A and identified AM-18002, an anmindenol A derivative, as a promising anticancer agent. The combination of AM-18002 and ionizing radiation (IR) improved anticancer effects, which were exerted by promoting apoptosis and inhibiting the proliferation of FM3A mouse breast cancer cells. AM-18002 increased the production of reactive oxygen species (ROS) and was more effective in inducing DNA damage. AM-18002 treatment was found to inhibit the expansion of myeloid-derived suppressor cells (MDSC), cancer cell migration and invasion, and STAT3 phosphorylation. The AM-18002 and IR combination synergistically induced cancer cell death, and AM-18002 acted as a potent anticancer agent by increasing ROS generation and blocking MDSC-mediated STAT3 activation in breast cancer cells.

Cell metabolism: Functional and phenotypic single cell approaches

Several metabolic pathways are essential for the physiological regulation of immune cells, but their dysregulation can cause immune dysfunction. Hypermetabolic and hypometabolic states represent deviations in the magnitude and flexibility of effector cells in different contexts, for example in autoimmunity, infections or cancer. To study immunometabolism, most methods focus on bulk populations and rely on in vitro activation assays. Nowadays, thanks to the development of single-cell technologies, including multiparameter flow cytometry, mass cytometry, RNA cytometry, among others, the metabolic state of individual immune cells can be measured in a variety of samples obtained in basic, translational and clinical studies. Here, we provide an overview of different single-cell approaches that are employed to investigate both mitochondrial functions and cell dependence from mitochondria metabolism. Moreover, besides the description of the appropriate experimental settings, we discuss the strengths and weaknesses of different approaches with the aim to suggest how to study cell metabolism in the settings of interest.

Phospholipid scramblase 3: a latent mediator connecting mitochondria and heavy metal apoptosis

Lead and mercury are the ubiquitous heavy metals triggering toxicity and initiating apoptosis in cells. Though the toxic effects of heavy metals on various organs are known, there is a paucity of information on the mechanisms that instigate the current study. A plausible role of phospholipid scramblase 3 (PLSCR3) in Pb2+ and Hg2+ induced apoptosis was investigated with human embryonic kidney (HEK 293) cells. After 12 h of exposure, ~30-40% of the cells were in the early stage of apoptosis with increased reactive oxygen species (ROS), decreased mitochondrial membrane potential, and increased intracellular calcium levels. Also, ~20% of the cardiolipin localized within the inner mitochondrial membrane was translocated to the outer mitochondrial membrane along with the mobilization of truncated Bid (t-Bid) to the mitochondria and cytochrome c from the mitochondria. The endogenous expression levels of PLSCR3, caspase 8, and caspase 3 were upregulated in Pb2+ and Hg2+ induced apoptosis. The activation and upregulation of PLSCR3 mediate CL translocation playing a potential role in initiating the heavy metal-induced apoptosis. Therefore, PLSCR3 could be the linker between mitochondria and heavy metal apoptosis.

PW06 Triggered Fas-FADD to Induce Apoptotic Cell Death In Human Pancreatic Carcinoma MIA PaCa-2 Cells through the Activation of the Caspase-Mediated Pathway

Pancreatic cancer has higher incidence and mortality rates worldwide. PW06 [(E)-3-(9-ethyl-9H-carbazol-3-yl)-1-(2,5-dimethoxyphenyl) prop-2-en-1-one] is a carbazole derivative containing chalcone moiety which was designed for inhibiting tumorigenesis in human pancreatic cancer. This study is aimed at investigating PW06-induced anticancer effects in human pancreatic cancer MIA PaCa-2 cells in vitro. The results showed PW06 potent antiproliferative/cytotoxic activities and induced cell morphological changes in a human pancreatic cancer cell line (MIA PaCa-2), and these effects are concentration-dependent (IC₅₀ is 0.43 μM). Annexin V and DAPI staining assays indicated that PW06 induced apoptotic cell death and DNA condensation. Western blotting indicated that PW06 increased the proapoptotic proteins such as Bak and Bad but decreased the antiapoptotic protein such as Bcl-2 and Bcl-xL. Moreover, PW06 increased the active form of caspase-8, caspase-9, and caspase-3, PARP, releasing cytochrome c, AIF, and Endo G from mitochondria in MIA PaCa-2 cells. Confocal laser microscopy assay also confirmed that PW06 increased Bak and decreased Bcl-xL. Also, the cells were pretreated with inhibitors of caspase-3, caspase-8, and caspase-9 and then were treated with PW06, resulting in increased viable cell number compared to PW06 treated only. Furthermore, PW06 showed a potent binding ability with hydrophobic interactions in the core site of the Fas-Fas death domains (FADD). In conclusion, PW06 can potent binding ability to the Fas-FADD which led to antiproliferative, cytotoxic activities, and apoptosis induction accompanied by the caspase-dependent and mitochondria-dependent pathways in human pancreatic cancer MIA PaCa-2 cells.

Multiple variants of the human presequence translocase motor subunit Magmas govern the mitochondrial import

Mitochondrial protein translocation is an intricately regulated process that requires dedicated translocases at the outer and inner membranes. The presequence translocase complex, translocase of the inner membrane 23, facilitates most of the import of preproteins containing presequences into the mitochondria, and its primary structural organization is highly conserved. As part of the translocase motor, two J-proteins, DnaJC15 and DnaJC19, are recruited to form two independent translocation machineries (translocase A and translocase B, respectively). On the other hand, the J-like protein subunit of translocase of the inner membrane 23, Mitochondria-associated granulocyte-macrophage colony-stimulating factor signaling molecule (Magmas) (orthologous to the yeast subunit Pam16), can regulate human import-motor activity by forming a heterodimer with DnaJC19 and DnaJC15. However, the precise coordinated regulation of two human import motors by a single Magmas protein is poorly understood. Here, we report two additional Magmas variants (Magmas-1 and Magmas-2) constitutively expressed in the mammalian system. Both the Magmas variants are functional orthologs of Pam16 with an evolutionarily conserved J-like domain critical for cell survival. Moreover, the Magmas variants are peripherally associated with the inner membrane as part of the human import motor for translocation. Our results demonstrate that Magmas-1 is predominantly recruited to translocase B, whereas Magmas-2 is majorly associated with translocase A. Strikingly, both the variants exhibit differential J-protein inhibitory activity in modulating import motor, thereby regulating overall translocase function. Based on our findings, we hypothesize that additional Magmas variants are of evolutionary significance in humans to maximize protein import in familial-linked pathological conditions.

Initiation and Execution of Programmed Cell Death and Regulation of Reactive Oxygen Species in Plants

Programmed cell death (PCD) plays crucial roles in plant development and defence response. Reactive oxygen species (ROS) are produced during normal plant growth, and high ROS concentrations can change the antioxidant status of cells, leading to spontaneous cell death. In addition, ROS function as signalling molecules to improve plant stress tolerance, and they induce PCD under different conditions. This review describes the mechanisms underlying plant PCD, the key functions of mitochondria and chloroplasts in PCD, and the relationship between mitochondria and chloroplasts during PCD. Additionally, the review discusses the factors that regulate PCD. Most importantly, in this review, we summarise the sites of production of ROS and discuss the roles of ROS that not only trigger multiple signalling pathways leading to PCD but also participate in the execution of PCD, highlighting the importance of ROS in PCD.

Studies on the Mechanism of Alloimperatorin on the Proliferation and Apoptosis of HeLa Cells

Alloimperatorin is a compound extracted from the traditional Chinese medicine (Angelica dahurica), which has exhibited anticancer activity. However, its precise molecular mechanism of anticancer remains unclear. Alloimperatorin-induced apoptosis of cervical cancer cells and its molecular mechanism were investigated in the present study. Cholecystokinin octapeptide (CCK-8) was employed to evaluate the cytotoxicity of alloimperatorin on HeLa, SiHa, and MS-751 cells. Flow cytometry was used to assess apoptosis induced by alloimperatorin. The mechanism of apoptosis was verified by mitochondrial membrane potential, Western blotting, and fluorescent PCR. The results of the study showed that alloimperatorin reduced the activity of HeLa cells. The calculated IC50 at 48 hours was 116.9 μM. Compared with the control group, alloimperatorin increased the apoptotic rate of HeLa cells and reduced the mitochondrial membrane potential of HeLa cells. The Western blot results showed that alloimperatorin promotes the expression of caspase3, 8, 9 and that Bax apoptotic proteins reduce PARP expression, procaspase3, 8, 9, and BCL-2 proteins and reduces the cyt-c in the mitochondria expression. The results demonstrated that alloimperatorin can induce HeLa cell apoptosis through mitochondria and extrinsic apoptotic pathways.

The Mechanism of Action of Salsolinol in Brain: Implications in Parkinson's Disease

1-Methyl-1,2,3,4-tetrahydroisoquinoline-6,7-diol, commonly known as salsolinol, is a compound derived from dopamine. It was first discovered in 1973 and has gained attention for its role in Parkinson's disease. Salsolinol and its derivatives were claimed to play a role in the pathogenesis of Parkinson's disease as a neurotoxin that induces apoptosis of dopaminergic neurons due to its structural similarity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its ability to induce Parkinsonism. In this article, we discussed the biosynthesis, distribution and blood-brain barrier permeability of salsolinol. The roles of salsolinol in a healthy brain, particularly the interactions with enzymes, hormone and catecholamine, were reviewed. Finally, we discussed the involvement of salsolinol and its derivatives in the pathogenesis of Parkinson's disease.

Physcion, a tetra-substituted 9,10-anthraquinone, prevents homocysteine-induced endothelial dysfunction by activating Ca2+- and Akt-eNOS-NO signaling pathways

BACKGROUND

Homocysteine (Hcy) induced vascular endothelial dysfunction is known to be closely associated with oxidative stress and impaired NO system. 1,8-Dihydroxy-3-methoxy-6-methylanthracene-9,10-dione (physcion) has been known to has antioxidative and anti-inflammatory properties.

PURPOSE

The purpose of the present study was to define the protective effect of physcion on Hcy-induced endothelial dysfunction and its mechanisms involved.

STUDY DESIGN AND METHODS

Hyperhomocysteinemia (HHcy) rat model was induced by feeding 3% methionine. A rat thoracic aortic ring model was used to investigate the effects of physcion on Hcy-induced impairment of endothelium-dependent relaxation. Two doses, low (L, 30 mg/kg/day) and high (H, 50 mg/kg/day) of physcion were used in the present study. To construct Hcy-injured human umbilical vein endothelial cells (HUVECs) model, the cells treated with 3 mM Hcy. The effects of physcion on Hcy-induced HUVECs cytotoxicity and apoptosis were studied using MTT and flow cytometry. Confocal analysis was used to determine the levels of intracellular Ca2+. The levels of protein expression of the apoptosis-related markers Bcl-2, Bax, caspase-9/3, and Akt and endothelial nitric oxide synthase (eNOS) were evaluated by western blot.

RESULTS

In the HHcy rat model, plasma levels of Hcy and malondialdehyde (MDA) were elevated (20.45 ± 2.42 vs. 4.67 ± 1.94 μM, 9.42 ± 0.48 vs. 3.47 ± 0.59 nM, p < 0.001 for both), whereas superoxide dismutase (SOD) and nitric oxide (NO) levels were decreased (77.11 ± 4.78 vs. 115.02 ± 5.63 U/ml, 44.51 ± 4.45 vs. 64.18 ± 5.34 μM, p < 0.001 and p < 0.01, respectively). However, treatment with physcion significantly reversed these changes (11.82 ± 2.02 vs. 20.45 ± 2.42 μM, 5.97 ± 0.72 vs. 9.42 ± 0.48 nM, 108.75 ± 5.65 vs. 77.11 ± 4.78 U/ml, 58.14 ± 6.02 vs. 44.51 ± 4.45 μM, p < 0.01 for all). Physcion also prevented Hcy-induced impairment of endothelium-dependent relaxation in HHcy rats (1.56 ± 0.06 vs. 15.44 ± 2.53 nM EC50 for ACh vasorelaxation, p < 0.05 vs. HHcy). In Hcy-injured HUVECs, physcion inhibited the impaired viability, apoptosis and reactive oxygen species. Hcy treatment significantly increased the protein phosphorylation levels of p38 (2.26 ± 0.20 vs. 1.00 ± 0.12, p <0.01), ERK (2.11 ± 0.21 vs. 1.00 ± 0.11, p <0.01) and JNK. Moreover, physcion reversed the Hcy-induced apoptosis related parameter changes such as decreased mitochondrial membrane potential (MMP) and Bcl-2/Bax protein ratio, and increased protein expression of caspase-9/3 in HUVECs. Furthermore, the downregulation of Ca2+, Akt, eNOS and NO caused by Hcy were recovered with physcion treatment in HUVECs.

CONCLUSION

Physcion prevents Hcy-induced endothelial dysfunction by activating Ca2+- and Akt-eNOS-NO signaling pathways. This study provides the first evidence that physcion might be a candidate agent for the prevention of cardiovascular disease induced by Hcy.

Mechanisms underlying the protective effect of tannic acid against arsenic trioxide‑induced cardiotoxicity in rats: Potential involvement of mitochondrial apoptosis

Arsenic trioxide (ATO) is a frontline chemotherapy drug used in the therapy of acute promyelocytic leukemia. However, the clinical use of ATO is hindered by its cardiotoxicity. The present study aimed to observe the potential effects and underlying mechanisms of tannic acid (TA) against ATO-induced cardiotoxicity. Male rats were intraperitoneally injected with ATO (5 mg/kg/day) to induce cardiotoxicity. TA (20 and 40 mg/kg/day) was administered to evaluate its cardioprotective efficacy against ATO-induced heart injury in rats. Administration of ATO resulted in pathological damage in the heart and increased oxidative stress as well as levels of serum cardiac biomarkers creatine kinase and lactate dehydrogenase and the inflammatory marker NF-κB (p65). Conversely, TA markedly reversed this phenomenon. Additionally, TA treatment caused a notable decrease in the expression levels of cleaved caspase-3/caspase-3, Bax, p53 and Bad, while increasing Bcl-2 expression levels. Notably, the application of TA decreased the expression levels of cytochrome c, second mitochondria-derived activator of caspases and high-temperature requirement A2, which are apoptosis mitochondrial-associated proteins. The present findings indicated that TA protected against ATO-induced cardiotoxicity, which may be associated with oxidative stress, inflammation and mitochondrial apoptosis.

Macrophage migration inhibitory factor inhibition as a novel therapeutic approach against triple-negative breast cancer

Triple-negative breast cancer (TNBC), defined as loss of estrogen, progesterone, and Her2 receptors, is a subtype of highly aggressive breast cancer with worse prognosis and poor survival rate. Macrophage migration inhibitory factor (MIF) is a pleiotropic pro-inflammatory cytokine aberrantly expressed in many solid tumors and known to promote tumor progression and metastasis. However, its role in TNBC progression and metastasis is unexplored. Here we have shown that in TNBC patients, MIF expression was significantly enriched in the tumor compared to adjacent normal tissue. Using publically available patient datasets, we showed that MIF overexpression correlates with worse survival in TNBC compared to other hormonal status. Orthotopic implantation of TNBC cells into MIF knockout mice showed reduced tumor growth compared to wild-type mice. In addition, we have shown that MIF downregulation inhibits TNBC growth and progression in a syngeneic mouse model. We further showed that CPSI-1306, a small-molecule MIF inhibitor, inhibits the growth of TNBC cells in vitro. Mechanistic studies revealed that CPSI-1306 induces intrinsic apoptosis by alteration in mitochondrial membrane potential, cytochrome c (Cyt c) release, and activation of different caspases. In addition, CPSI-1306 inhibits the activation of cell survival and proliferation-related molecules. CPSI-1306 treatment also reduced the tumor growth and metastasis in orthotopic mouse models of mammary carcinoma. CPSI-1306 treatment of tumor-bearing mice significantly inhibited TNBC growth and pulmonary metastasis in a dose-dependent manner. Histological analysis of xenograft tumors revealed a higher number of apoptotic cells in CPSI-1306-treated tumors compared to vehicle controls. Our studies, for the first time, show that MIF overexpression in TNBC enhances growth and metastasis. Taken together, our results indicate that using small molecular weight MIF inhibitors could be a promising strategy to inhibit TNBC progression and metastasis.

Repair of Tea Polysaccharide Promotes the Endocytosis of Nanocalcium Oxalate Monohydrate by Damaged HK-2 Cells

Endocytosis is a protective mechanism of renal epithelial cells to eliminate retained crystals. This research investigated the endocytosis of 100 nm calcium oxalate monohydrate crystals in human kidney proximal tubular epithelial (HK-2) cells before and after repair by four kinds of tea polysaccharides with molecular weights (MWs) of 10.88 (TPS0), 8.16 (TPS1), 4.82 (TPS2), and 2.31 kDa (TPS3), respectively. When HK-2 cells were repaired by TPSs after oxalic acid injury, the cell viability, wound healing ability, mitochondrial membrane potential, percentage of cells with endocytosed crystals, and dissolution rate of the endocytosed crystals increased; the cell morphology recovered; and the reactive oxygen level and lactate dehydrogenase release decreased. Most of the endocytosed crystals were found in the lysosomes. The repair effects of the four TPSs were ranked in the following order: TPS2>TPS1>TPS3>TPS0. TPS2 with moderate MW presented the optimal repair ability and strongest ability to promote endocytosis.

Heavy-Metals-Mediated Phospholipids Scrambling by Human Phospholipid Scramblase 3: A Probable Role in Mitochondrial Apoptosis

Human phospholipid scramblases are a family of four homologous transmembrane proteins (hPLSCR1-4) mediating phospholipids (PLs) translocation in plasma membrane upon Ca²⁺ activation. hPLSCR3, the only homologue localized to mitochondria, plays a vital role in mitochondrial structure, function, maintenance, and apoptosis. Upon Ca²⁺ activation, hPLSCR3 mediates PL translocation at the mitochondrial membrane enhancing t-bid-induced cytochrome c release and apoptosis. Mitochondria are important target organelles for heavy-metals-induced apoptotic signaling cascade and are the central executioner of apoptosis to trigger. Pb²⁺ and Hg²⁺ toxicity mediates apoptosis by increased reactive oxygen species (ROS) and cytochrome c release from mitochondria. To discover the role of hPLSCR3 in heavy metal toxicity, hPLSCR3 was overexpressed as a recombinant protein in Escherichia coli Rosetta (DE3) and purified by affinity chromatography. The biochemical assay using synthetic proteoliposomes demonstrated that hPLSCR3 translocated aminophospholipids in the presence of micromolar concentrations of Pb²⁺ and Hg²⁺. A point mutation in the Ca²⁺-binding motif (F258V) led to a ∼60% loss in the functional activity and decreased binding affinities for Pb²⁺ and Hg²⁺ implying that the divalent heavy metal ions bind to the Ca²⁺-binding motif. This was further affirmed by the characteristic spectra observed with stains-all dye. The conformational changes upon heavy metal binding were monitored by circular dichroism, intrinsic tryptophan fluorescence, and light-scattering studies. Our results revealed that Pb²⁺ and Hg²⁺ bind to hPLSCR3 with higher affinity than Ca²⁺ thus mediating scramblase activity. To summarize, this is the first biochemical evidence for heavy metals binding to the mitochondrial membrane protein leading to bidirectional translocation of PLs specifically toward phosphatidylethanolamine.

Down-regulation of GAS5 ameliorates myocardial ischaemia/reperfusion injury via the miR-335/ROCK1/AKT/GSK-3β axis

Growth arrest‐specific transcript 5 (GAS5), along non‐coding RNA (LncRNA), is highly expressed in hypoxia/reoxygenation (H/R)‐cardiomyocytes and promotes H/R‐induced apoptosis. In this study, we determined whether down‐regulation of GAS5 ameliorates myocardial ischaemia/reperfusion (I/R) injury and further explored its mechanism. GAS5 expression in cardiomyocytes and rats was knockdown by transfected or injected with GAS5‐specific small interfering RNA or adeno‐associated virus delivering small hairpin RNAs, respectively. The effects of GAS5 knockdown on myocardial I/R injury were detected by CCK‐8, myocardial enzyme test, flow cytometry, TTC and terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) staining. qRT‐PCR and luciferase reporter assay were carried out to analyse the relationship between GAS5 and miR‐335. The regulation of GAS5 on Rho‐associated protein kinase 1 (ROCK1) expression, the activation of PI3K/AKT/GSK‐3β pathway and mitochondrial permeability transition pore (mPTP) opening was further evaluated. The results indicated that GAS5 knockdown enhanced the viability, decreased apoptosis and reduced the levels of lactate dehydrogenase and creatine kinase‐MB in H/R‐treatment cardiomyocytes. Meanwhile, down‐regulation of GAS5 limited myocardial infarct size and reduced apoptosis in I/R‐heart. GAS5 was found to bind to miR‐335 and displayed a reciprocal inhibition between them. Furthermore, GAS5 knockdown repressed ROCK1 expression, activated PI3K/AKT, thereby leading to inhibition of GSK‐3β and mPTP opening. These suppressions were abrogated by miR‐335 inhibitor treatment. Taken together, our results demonstrated that down‐regulation of GAS5 ameliorates myocardial I/R injury via the miR‐335/ROCK1/AKT/GSK‐3β axis. Our findings suggested that GAS5 may be a new therapeutic target for the prevention of myocardial I/R injury.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.

Fisetin Inhibits Cell Proliferation through the Induction of G0/G1 Phase Arrest and Caspase-3-Mediated Apoptosis in Mouse Leukemia Cells

Fisetin, a naturally occurring flavonoid, is found in common fruits and vegetables and has been shown to induce cytotoxic effects in many human cancer cell lines. No information has shown that fisetin induced cell cycle arrest and apoptosis in mouse leukemia WEHI-3 cells. We found that fisetin decreased total viable cells through G₀/G₁ phase arrest and induced sub-G₁ phase (apoptosis). We have confirmed fisetin induced cell apoptosis by the formation of DNA fragmentation and induction of apoptotic cell death. Results indicated that fisetin induced intracellular Ca 2+ increase but decreased the ROS production and the levels of ΔΨ m in WEHI-3 cells. Fisetin increased the activities of caspase-3, -8 and -9. Cells were pre-treated with inhibitors of caspase-3, -8 and -9 and then treated with fisetin and results showed increased viable cell number when compared to fisetin treated only. Fisetin reduced expressions of cdc25a but increased p-p53, Chk1, p21 and p27 that may lead to G₀/G₁ phase arrest. Fisetin inhibited anti-apoptotic protein Bcl-2 and Bcl-xL and increased pro-apoptotic protein Bax and Bak. Furthermore, fisetin increased the protein expression of cytochrome c and AIF. Fisetin decreased cell number through G₀/G₁ phase arrest via the inhibition of cdc25c and induction of apoptosis through caspase-dependent and mitochondria-dependent pathways. Therefore, fisetin may be useful as a potential therapeutic agent for leukemia.

ROS Induced by KillerRed Targeting Mitochondria (mtKR) Enhances Apoptosis Caused by Radiation via Cyt c/Caspase-3 Pathway

During radiotherapy, reactive oxygen species- (ROS-) induced apoptosis is one of the main mechanism of radiation. Based on KillerRed which can induce ROS burst in different cell substructures, here we hypothesized that KillerRed targeting mitochondria (mtKR) could induce ROS to enhance apoptosis by radiation. In this study, empty vector, mtKR, and mtmCherry plasmids were successfully constructed, and mitochondrial localization were detected in COS-7 and HeLa cells. After HeLa cells were transfected and irradiated by visible light and X-rays, ROS levels, mitochondrial membrane potential (Δψ_m), ATPase activities, adenosine triphosphate (ATP) content, apoptosis, and the expressions of mRNA and protein were measured, respectively. Data demonstrated that the ROS levels significantly increased after light exposure, and adding extra radiation, voltage-dependent anion channel 1 (VDAC1) protein increased in the mitochondria, while Na⁺-K⁺ and Ca²⁺-Mg²⁺ ATPase activities, ATP content, and Δψ_m significantly reduced. Additionally, the cell apoptotic rates dramatically increased, which referred to the increase of cytochrome c (Cyt c), caspase-9, and caspase-3 mRNA expressions, and Cyt c protein was released from the mitochondria into the cytoplasm; caspase-9 and -3 were activated. These results indicated that mtKR can increase the production of ROS, enhance mitochondrial dysfunction, and strengthen apoptosis by radiation via Cyt c/caspase-3 pathway.

Hydroxytyrosol protects against myocardial ischemia reperfusion injury by inhibiting mitochondrial permeability transition pore opening

Hydroxytyrosol (HT), a phenolic compound extracted from olive oil, is reported to protect against myocardial ischemia reperfusion injury (MIRI), but its mechanism has not been fully elucidated. The mitochondria permeability transition pore (MPTP) is an important therapeutic target for MIRI. The present study aimed to investigate the role of MPTP in the cardioprotection of HT. Isolated rat hearts were mounted on a Langendorff apparatus and subjected to 30 min of ischemia followed by 120 min of reperfusion to mimic a MIRI model. Isolated hearts were pretreated with different doses of HT (10, 100 and 1,000 µM) for 10 min prior to ischemia. Myocardial infarct size was detected using TTC staining. Changes in myocardial cell structure were observed using hematoxylin and eosin staining. MPTP opening was detected spectrophotometrically. Myocardial cell apoptosis was observed with terminal deoxynucleotidyl-transferase-mediated dUTP nick end labeling assays. The expression of apoptosis-associated proteins was measured by western blot analysis. The data revealed that HT (100 and 1,000 µM) treatment significantly alleviated pathological damage in ischemic myocardium and reduced myocardial infarct size compared with the untreated control. However, no significant difference was observed in the 10 µM HT treatment group compared with the untreated control. It was further revealed that HT decreased the B cell lymphoma-2 (Bcl-2)-like protein 4 (Bax)/Bcl-2 ratio, suppressed MPTP opening and subsequently decreased the expression of cytochrome c, cleaved caspase-9 and -3, thereby inhibiting apoptosis. Additionally, the beneficial effects of HT on MIRI were reversed by atractyloside, which induces MPTP opening. In conclusion, the present study demonstrated that HT inhibited MPTP opening, partially via modulation of Bax and Bcl-2, thereby protecting against MIRI and thereby providing a pharmacological basis for future research and treatment of MIRI.

Ultrastructural Study of Rat Testis Following Conventional Phototherapy during Neonatal Period

Introduction

Phototherapy is the most common treatment for neonatal jaundice. This study sought to determine ultrastructural changes in testis, at different time-points, after 48 hours of conventional phototherapy was given to newborn rats.

Methods

Newborn male Wistar rats (n = 36) were divided into two groups as follows - group 1 (G1), control (without phototherapy) and group 2 (G2), exposure to conventional phototherapy for 48 h. Six animals from each group were sacrificed on postnatal days (PND) 70, 100 and 130. The testes were dissected out and processed for Transmission Electron Microscopy (TEM).

Results

TEM showed that G2 on PND 70 and 100 showed damaged organelles, including nuclei, mitochondria, endoplasmic reticulum, vacuoles and electron dense bodies in the testes. Seminiferous Tubule on PND130 showed lesser damage. On PND70 ST wall thickness (STWT) of G2 was significantly higher (P < 0.001) than G1 STWT of G2 was significantly lower than G1 on PND100 (P = 0.047) and on PND130 (P < 0.001). Mitochondrial diameter in spermatogonia was significantly higher in G2 on PND70 (P = 0.001), PND100 (P = 0.031) and PND130 (P = 0.028). Primary spermatocytes in G2 also had larger mitochondria on PND70 (P < 0.001), PND100 (P = 0.007) and PND130 (P = 0.008). Further, spermatids had larger mitochondria in G2 on PND70 (P < 0.001), PND100 (P = 0.044) and PND130 (P < 0.001).

Conclusion

Phototherapy causes degenerative changes in rat testis on PND70 and 100 that partially recover by PND 130.

Walnut ( Juglans regia) Peptides Reverse Sleep Deprivation-Induced Memory Impairment in Rat via Alleviating Oxidative Stress

The aim of this study was to determine the neuroprotective effects of walnut protein hydrolysates (WPH) against memory deficits induced by sleep deprivation (SD) in rat and further to identify and characterize the potent neuroprotective peptides against glutamate-induced apoptosis in PC12 cells. Results showed that a remarkable amelioration effect on behavioral performance in Morris water maze test was observed for WPH and its low molecular weight fraction WPHL, especially for WPHL. Additionally, a reduction of antioxidant defense (catalase, glutathione peroxidase (GSH-px), and superoxide dismutase (SOD)) and an increase of malondialdehyde content induced by SD were normalized in brain of rat after oral administration of WPH and WPHL. Then three neuroprotective peptides including GGW, VYY, and LLPF were identified from WPHL, which could protect PC12 cells against glutamate-induced apoptosis with relative cell viability of 78.29 ± 3.09%, 80.65 ± 1.74%, and 83.97 ± 3.06%, respectively, versus glutamate group 48.61 ± 3.99%. The possible mechanism underlying their protective effects of GGW and VYY could be related to their strong radical scavenging activity as well as their ability to reduce reactive oxygen species production and the depletion of SOD and GSH-px in PC12 cells. Notably, the marked neuroprotective effects of LLPF, which did not show obvious free-radical scavenging activity in vitro, could be attributed to its strong effects on inhibiting Ca²⁺ influx and mitochondrial membrane potential collapse. Additionally, all these peptides could regulate the expression of apoptosis-related proteins (Bax and Bcl-2). Therefore, walnut peptides might be regarded as the potential nutraceuticals against neurodegenerative disorders associated with memory deficits.

An Apoptotic and Endosymbiotic Explanation of the Warburg and the Inverse Warburg Hypotheses

Otto Warburg, a Nobel prize winner, observed that cancer cells typically “switch” from aerobic to anaerobic respiration. He hypothesized that mitochondrial damage induces neoplastic transformation. In contrast, pathological aging is observed mainly in neuron cells in neurodegenerative diseases. Oxidative respiration is particularly active in neurons. There is inverse comorbidity between cancer and neurodegenerative diseases. This led to the creation of the “inverse Warburg hypothesis”, according to which excessive mitochondrial activity induces pathological aging. The findings of our studies suggest that both the Warburg effect and the “inverse Warburg hypothesis” can be elucidated by the activation or suppression of apoptosis through oxidative respiration. The key outcome of our phylogenetic studies was the discovery that apoptosis and apoptosis-like cell death evolved due to an evolutionary “arms race” conducted between “prey” protomitochondrion and “predator” primitive eukaryotes. The ancestral protomitochondrial machinery produces and releases toxic mitochondrial proteins. Extant apoptotic factors evolved from these toxins. Our experiments indicate that the mitochondrial machinery is directly involved in adaptation to aerobic conditions. Additionally, our hypothesis is supported by the fact that different apoptotic factors are directly involved in respiration.

Neuroprotective Effects of Acetylcholinesterase Inhibitory Peptides from Anchovy (Coilia mystus) against Glutamate-Induced Toxicity in PC12 Cells

Ameliorations of cholinergic system dysfunction and oxidative stress in neurodegenerative diseases were main approaches to improve memory disorder. Our previous investigation showed that anchovy protein hydrolysate (APH) could attenuate scopolamine-induced memory deficits in mice by regulating acetylcholinesterase (AChE) activity. Therefore, peptides with AChE inhibitory activity in APH were explored and identified in this study, and their possible neuroprotective mechanisms on glutamate induced apoptosis in PC12 were also elucidated. Two peptides with strong AChE inhibitory capacity were identified as Pro-Ala-Tyr-Cys-Ser (PAYCS) and Cys-Val-Gly-Ser-Tyr (CVGSY) by ultraperformance liquid chromatography coupled with tandem mass spectrometry. The AChE inhibitory was 23.68 ± 0.97% and 6.08 ± 0.41%, respectively. Treatment with PAYCS and CVGSY could significantly (p < 0.05) increase cells viability, reduce lactate dehydrogenase release, reactive oxygen species (ROS) production, malondialdehyde content, and the ratio of Bax/Bcl-2 of glutamate-induced apoptosis PC12 cells (82.78 ± 6.58 and 109.94 ± 7.16% of control, respectively) as well as increase superoxide dismutase and GSH-px activities. In addition, both the peptides could inhibit Ca²⁺ influx but have no effects on mitochondrial membrane potential. Results indicated that AChE inhibitory peptides (PAYCS and CVGSY) possibly protected the PC12 cells against glutamate-induced apoptosis via inhibiting ROS production and Ca²⁺ influx. PAYCS and CVGSY might be considered as nutraceuticals for alleviating memory deficits.

Iron oxide nanoparticles induced cytotoxicity, oxidative stress and DNA damage in lymphocytes

Over the past few decades nanotechnology and material science has progressed extremely rapidly. Iron oxide nanoparticles (IONPs) owing to their unique magnetic properties have a great potential for their biomedical and bioengineering applications. However, there is an inevitable need to address the issue of safety and health effects of these nanoparticles. Hence, the present study was aimed to assess the cytotoxic effects of IONPs on rats' lymphocytes. Using different assays, we studied diverse parameters including mitochondrial membrane potential, intracellular accumulation of reactive oxygen species (ROS), lactate dehydrogenase activity, antioxidant enzymes activity and DNA damage measurements. Intracellular metal uptake and ultrastructure analysis were also carried out through inductively coupled plasma atomic emission spectroscopy, transmission electron microscopy respectively. The results show that the IONP-induced oxidative stress was concentration-dependent in nature, with significant (P < 0.05) increase in ROS levels, lipid peroxidation level as well as depletion of antioxidant enzymes and glutathione. Moreover, we observed morphological changes in the cell after intracellular uptake and localization of nanoparticles in cells. From the findings of the study, it may be concluded that IONPs induce ROS-mediated cytotoxicity in lymphocytes. Copyright © 2017 John Wiley & Sons, Ltd.

Mitochondrial dysfunction and oxidative stress in corneal disease

The cornea is the anterior transparent surface and the main refracting structure of the eye. Mitochondrial dysfunction and oxidative stress are implicated in the pathogenesis of inherited (e.g. Kearns Sayre Syndrome) and acquired corneal diseases (e.g. keratoconus and Fuchs endothelial corneal dystrophy). Both antioxidants and reactive oxygen species are found in the healthy cornea. There is increasing evidence of imbalance in the oxidative balance and mitochondrial function in the cornea in disease states. The cornea is vulnerable to mitochondrial dysfunction and oxidative stress due to its highly exposed position to ultraviolet radiation and high oxygen tension. The corneal endothelium is vulnerable to accumulating mitochondrial DNA (mtDNA) damage due to the post- mitotic nature of endothelial cells, yet their mitochondrial genome is continually replicating and mtDNA mutations can develop and accumulate with age. The unique physiology of the cornea predisposes this structure to oxidative damage, and there is interplay between inherited and acquired mitochondrial dysfunction, oxidative damage and a number of corneal diseases. By targeting mitochondrial dysfunction in corneal disease, emerging treatments may prevent or reduce visual loss.

The neurochemistry of peripheral nerve regeneration

Peripheral nerve injuries (PNIs) can be most disabling, resulting in the loss of sensitivity, motor function and autonomic control in the involved anatomical segment. Although injured peripheral nerves are capable of regeneration, sub-optimal recovery of function is seen even with the best reconstruction. Distal axonal degeneration is an unavoidable consequence of PNI. There are currently few strategies aimed to maintain the distal pathway and/or target fidelity during regeneration across the zone of injury. The current state of the art approaches have been focussed on the site of nerve injury and not on their distal muscular targets or representative proximal cell bodies or central cortical regions. This is a comprehensive literature review of the neurochemistry of peripheral nerve regeneration and a state of the art analysis of experimental compounds (inorganic and organic agents) with demonstrated neurotherapeutic efficacy in improving cell body and neuron survival, reducing scar formation and maximising overall nerve regeneration.

Protective effect of lavender oil on scopolamine induced cognitive deficits in mice and H2O2 induced cytotoxicity in PC12 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Lavender essential oil (LO), an aromatic liquid extracted from Lavandula angustifolia Mill., has been traditionally used in the treatments of many nervous system diseases, and recently LO also reported to be effective for the Alzheimer's disease (AD).

AIM OF THE STUDY

The improvement effect of lavender oil (LO) on the scopolamine-induced cognitive deficits in mice and H₂O₂ induced cytotoxicity in PC12 cells have been evaluated. The relevant mechanism was also researched from the perspective of antioxidant effect and cholinergic system modulation.

MATERIALS AND METHODS

Cognitive deficits were induced in C57BL/6J mice treated with scopolamine (1mg/kg, i.p.) and were assessed by Morris water maze (MWM) and step-through passive avoidance tests. Then their hippocampus were removed for biochemical assays (acetylcholinesterase (AChE), superoxide dismutase (SOD), glutathione peroxidase (GPX) and malondialdehyde (MDA)). In vitro, the cytotoxicity were induced by 4h exposure to H₂O₂ in PC12 and evaluated by cell viability (MTT), lactate dehydrogenase (LDH) level, nitric oxide (NO) release, reactive oxygen species (ROS) production and mitochondrial membrane potential (MMP).

RESULTS

The results demonstrated that LO (100mg/kg) could improve the cognitive performance of scopolamine induced mice in behavioral tests. Meanwhile, it significantly decreased the AChE activity, MDA level, and increase SOD and GPX activities of the model. Moreover, LO (12μg/mL) protected PC12 cells from H₂O₂ induced cytotoxicity by reducing LDH, NO release, intracellular ROS accumulation and MMP loss.

CONCLUSIONS

It was suggested that LO could show neuroprotective effect in AD model in vivo (scopolamine-treated mice) and in vitro (H₂O₂ induced PC12 cells) via modulating oxidative stress and AChE activity.

Identification of Mitochondrial Genome-Encoded Small RNAs Related to Egg Deterioration Caused by Postovulatory Aging in Rainbow Trout

Many factors have been reported to affect rainbow trout egg quality, among which, postovulatory aging is one of the most significant causes as reared rainbow trout do not usually volitionally oviposit the ovulated eggs. In order to uncover the genetic regulation underling egg deterioration caused by postovulatory aging in rainbow trout, mitochondrial genome-encoded small RNA (mitosRNAs) were analyzed from unfertilized eggs on Days 1, 7, and 14 postovulation with fertilization rates of 91.8, 73.4, and less than 50 %, respectively. A total of 248 mitosRNAs were identified from Illumina high-throughput sequencing of the small RNA libraries derived from the eggs of ten females. Ninety-eight of the small RNAs exhibited more than a threefold difference in expression between eggs from females exhibiting high fertilization rates at Day 1 and low fertilization rates at Day 14. The differentially expressed mitosRNAs were predominantly derived from mitochondrial D-loop, tRNA, rRNA, COII, and Cytb gene regions. Real-time quantitative PCR analysis was carried out for 14 differentially expressed mitosRNAs, of which, 12 were confirmed to be consistent with the sequencing reads. Further characterization of the differentially expressed mitosRNAs may lead to the development of new biomarkers for egg quality in rainbow trout.

Key Targets for Multi-Target Ligands Designed to Combat Neurodegeneration

HIGHLIGHTS Compounds that interact with multiple targets but minimally with the cytochrome P450 system (CYP) address the many factors leading to neurodegeneration.Acetyl- and Butyryl-cholineEsterases (AChE, BChE) and Monoamine Oxidases A/B (MAO A, MAO B) are targets for Multi-Target Designed Ligands (MTDL).ASS234 is an irreversible inhibitor of MAO A >MAO B and has micromolar potency against the cholinesterases.ASS234 is a poor CYP substrate in human liver, yielding the depropargylated metabolite.SMe1EC2, a stobadine derivative, showed high radical scavenging property, in vitro and in vivo giving protection in head trauma and diabetic damage of endothelium.Control of mitochondrial function and morphology by manipulating fission and fusion is emerging as a target area for therapeutic strategies to decrease the pathological outcome of neurodegenerative diseases. Growing evidence supports the view that neurodegenerative diseases have multiple and common mechanisms in their aetiologies. These multifactorial aspects have changed the broadly common assumption that selective drugs are superior to "dirty drugs" for use in therapy. This drives the research in studies of novel compounds that might have multiple action mechanisms. In neurodegeneration, loss of neuronal signaling is a major cause of the symptoms, so preservation of neurotransmitters by inhibiting the breakdown enzymes is a first approach. Acetylcholinesterase (AChE) inhibitors are the drugs preferentially used in AD and that one of these, rivastigmine, is licensed also for PD. Several studies have shown that monoamine oxidase (MAO) B, located mainly in glial cells, increases with age and is elevated in Alzheimer (AD) and Parkinson's Disease's (PD). Deprenyl, a MAO B inhibitor, significantly delays the initiation of levodopa treatment in PD patients. These indications underline that AChE and MAO are considered a necessary part of multi-target designed ligands (MTDL). However, both of these targets are simply symptomatic treatment so if new drugs are to prevent degeneration rather than compensate for loss of neurotransmitters, then oxidative stress and mitochondrial events must also be targeted. MAO inhibitors can protect neurons from apoptosis by mechanisms unrelated to enzyme inhibition. Understanding the involvement of MAO and other proteins in the induction and regulation of the apoptosis in mitochondria will aid progress toward strategies to prevent the loss of neurons. In general, the oxidative stress observed both in PD and AD indicate that antioxidant properties are a desirable part of MTDL molecules. After two or more properties are incorporated into one molecule, the passage from a lead compound to a therapeutic tool is strictly linked to its pharmacokinetic and toxicity. In this context the interaction of any new molecules with cytochrome P450 and other xenobiotic metabolic processes is a crucial point. The present review covers the biochemistry of enzymes targeted in the design of drugs against neurodegeneration and the cytochrome P450-dependent metabolism of MTDLs.

SPATA4 Counteracts Etoposide-Induced Apoptosis via Modulating Bcl-2 Family Proteins in HeLa Cells

Spermatogenesis associated 4 (SPATA4) is a testis-specific gene first cloned by our laboratory, and plays an important role in maintaining the physiological function of germ cells. Accumulated evidence suggests that SPATA4 might be associated with apoptosis. Here we established HeLa cells that stably expressed SPATA4 to investigate the function of SPATA4 in apoptosis. SPATA4 protected HeLa cells from etoposide-induced apoptosis through the mitochondrial apoptotic pathway, in the way that SPATA4 suppressed decrease of the mitochondrial membrane potential, the release of cytochrome c, and subsequent activation of caspase-9 and -3. We further demonstrated that SPATA4 upregulated anti-apoptotic members of Bcl-2 family proteins, Bcl-2, and downregulated the pro-apoptotic member of Bcl-2 family proteins, Bax. Knockdown of SPATA4 in HeLa/SPATA4 cells could partially rescue expression levels of bcl-2 and bax. In conclusion, SPATA4 protects HeLa cells against etoposide-induced apoptosis through the mitochondrial apoptotic pathway. Our findings provide further evidence that SPATA4 plays a role in regulating apoptosis.

Anti-tumor effect of morusin from the branch bark of cultivated mulberry in Bel-7402 cells via the MAPK pathway

In this experiment, the morusin separated from the branch bark of cultivated mulberry, an edible medicinal plant, is used to study the inhibition of morusin in the human hepatocellular carcinoma cell line Bel-7402.

The Effect of Hypoxic Preconditioning on Induced Schwann Cells under Hypoxic Conditions

OBJECT

Our objective was to explore the protective effects of hypoxic preconditioning on induced Schwann cells exposed to an environment with low concentrations of oxygen. It has been observed that hypoxic preconditioning of induced Schwann cells can promote axonal regeneration under low oxygen conditions.

METHOD

Rat bone marrow mesenchymal stem cells (MSCs) were differentiated into Schwann cells and divided into a normal oxygen control group, a hypoxia-preconditioning group and a hypoxia group. The ultrastructure of each of these groups of cells was observed by electron microscopy. In addition, flow cytometry was used to measure changes in mitochondrial membrane potential. Annexin V-FITC/PI staining was used to detect apoptosis, and Western blots were used to detect the expression of Bcl-2/Bax. Fluorescence microscopic observations of axonal growth in NG-108 cells under hypoxic conditions were also performed.

RESULTS

The hypoxia-preconditioning group maintained mitochondrial cell membrane and crista integrity, and these cells exhibited less edema than the hypoxia group. In addition, the cells in the hypoxia-preconditioning group were found to be in early stages of apoptosis, whereas cells from the hypoxia group were in the later stages of apoptosis. The hypoxia-preconditioning group also had higher levels of Bcl-2/Bax expression and longer NG-108 cell axons than were observed in the hypoxia group.

CONCLUSION

Hypoxic preconditioning can improve the physiological state of Schwann cells in a severe hypoxia environment and improve the ability to promote neurite outgrowth.

Lack of association between polymorphisms of the DNA base excision repair genes MUTYH and hOGG1 and keratoconus in a Polish subpopulation

INTRODUCTION

Keratoconus (KC) is a non-inflammatory thinning of the cornea and a leading indication for corneal transplantation. Oxidative stress plays a role in the pathogenesis of this disease. The products of the hOGG1 and MUTYH genes play an important role in the repair of oxidatively modified DNA in the base excision repair pathway. We hypothesized that variability in these genes may change susceptibility to oxidative stress and predispose individuals to the development of KC. We investigated the possible association between the c.977C>G polymorphism of the hOGG1 gene (rs1052133) and the c.972G>C polymorphism of the MUTYH gene (rs3219489) and KC occurrence as well as the modulation of this association by some KC risk factors.

MATERIAL AND METHODS

A total of 205 patients with KC and 220 controls were included in this study. The polymorphisms were genotyped with polymerase chain reaction (PCR) restriction fragment length polymorphism and PCR-confronting two-pair primer techniques. Differences in genotype and allele frequency distributions were evaluated using the χ(2) test, and KC risk was estimated with an unconditional multiple logistic regression with and without adjustment for co-occurrence of visual impairment, allergies, sex and family history for KC.

RESULTS

We did not find any association between the genotypes and combined genotypes of the c.977C>G polymorphism of the hOGG1 gene and the c.972G>C polymorphism of the MUTYH gene and the occurrence of KC.

CONCLUSIONS

Our findings suggest that the c.977C>G-hOGG1 polymorphism and the c.972G>C-MUTYH polymorphism may not be linked with KC occurrence in this Polish subpopulation.