Combined deficiency of Senataxin and DNA-PKcs causes DNA damage accumulation and neurodegeneration in spinal muscular atrophy.

Chronic low levels of survival motor neuron (SMN) protein cause spinal muscular atrophy (SMA). SMN is ubiquitously expressed, but the mechanisms underlying predominant neuron degeneration in SMA are poorly understood. We report that chronic low levels of SMN cause Senataxin (SETX)-deficiency, which results in increased RNA-DNA hybrids (R-loops) and DNA double-strand breaks (DSBs), and deficiency of DNA-activated protein kinase-catalytic subunit (DNA-PKcs), which impairs DSB repair. Consequently, DNA damage accumulates in patient cells, SMA mice neurons and patient spinal cord tissues. In dividing cells, DSBs are repaired by homologous recombination (HR) and non-homologous end joining (NHEJ) pathways, but neurons predominantly use NHEJ, which relies on DNA-PKcs activity. In SMA dividing cells, HR repairs DSBs and supports cellular proliferation. In SMA neurons, DNA-PKcs-deficiency causes defects in NHEJ-mediated repair leading to DNA damage accumulation and neurodegeneration. Restoration of SMN levels rescues SETX and DNA-PKcs deficiencies and DSB accumulation in SMA neurons and patient cells. Moreover, SETX overexpression in SMA neurons reduces R-loops and DNA damage, and rescues neurodegeneration. Our findings identify combined deficiency of SETX and DNA-PKcs stemming downstream of SMN as an underlying cause of DSBs accumulation, genomic instability and neurodegeneration in SMA and suggest SETX as a potential therapeutic target for SMA.

Habb-e-Asgand, polyherbal Unani formulation, protects liver and antioxidative enzymes against paracetamol induced hepatotoxicity.

Abstract Context: Habb-e-Asgand, a polyherbal Homeopathy/Unani drug from Hamdard Wakf Laboratory, India, used in arthritis, gout and joint pain, is a mixture of many herbal medicinal plants. Scientific attempts to test and validate its efficacy are meager. Objective: To evaluate the hepatoprotective and antioxidative potential of Habb-e-Asgand against paracetamol toxicity. Materials and methods: Swiss albino male mice (n = 5/group) were treated with Habb-e-Asgand (250 mg/kg, body weight (b.w.) in normal saline orally for 14 days followed by a single dose of paracetamol (400 mg/kg b.w./normal saline) intraperitoneally 24 h before euthanization. We estimated liver function (LFTs) using diagnostic kits, while antioxidant enzymes, cytochrome P450 (CYP) and lipid peroxidation (LPO) were measured using spectrophotometric methods. Results: Paracetamol alone induced LFTs enzymes significantly (p < 0.05 and p < 0.01, 0.001), serum glutamate pyruvate transaminase (SGPT, ∼70%), serum glutamate oxaloacetate transaminase (SGOT, ∼20%), alkaline phosphatase (ALP, ∼20%), total bilirubin (∼30%), CYP activity (∼50%) and LPO (∼45%), while it significantly inhibited the activity of antioxidant enzymes glutathione reductase (GR, ∼35%), glutathione peroxidase (GPx, ∼40%), glutathione S-tranferase (GST, ∼16%), catalase (CAT, ∼84%) and glutathione (GSH, ∼30%) contents. Habb-e-Asgand alone and in combination of paracetamol significantly (p < 0.05, 0.01, 0.001) decreased LFT levels (20-25%), CYP activity (∼45%) and LPO level (∼25%), while it induced antioxidant enzyme activity (GR, ∼15%; GPx, ∼17%; GST, ∼20% and CAT, ∼60%). Discussion: Paracetamol metabolites may be mediating production of reactive oxidant species (ROS) and liver injury, which are attenuated by Habb-e-Asgand antioxidant constituents. Conclusion: Habb-e-Asgand may be used as a prophylaxis for ROS related liver injury.

Exosomes in Vascular/Neurological Disorders and the Road Ahead.

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD), stroke, and aneurysms, are characterized by the abnormal accumulation and aggregation of disease-causing proteins in the brain and spinal cord. Recent research suggests that proteins linked to these conditions can be secreted and transferred among cells using exosomes. The transmission of abnormal protein buildup and the gradual degeneration in the brains of impacted individuals might be supported by these exosomes. Furthermore, it has been reported that neuroprotective functions can also be attributed to exosomes in neurodegenerative diseases. The potential neuroprotective functions may play a role in preventing the formation of aggregates and abnormal accumulation of proteins associated with the disease. The present review summarizes the roles of exosomes in neurodegenerative diseases as well as elucidating their therapeutic potential in AD, PD, ALS, HD, stroke, and aneurysms. By elucidating these two aspects of exosomes, valuable insights into potential therapeutic targets for treating neurodegenerative diseases may be provided.

Remote ischemic perconditioning is effective alone and in combination with intravenous tissue-type plasminogen activator in murine model of embolic stroke.

BACKGROUND AND PURPOSE: Remote ischemic conditioning is cardioprotective in myocardial infarction and neuroprotective in mechanical occlusion models of stroke. However, there is no report on its therapeutic potential in a physiologically relevant embolic stroke model (embolic middle cerebral artery occlusion) in combination with intravenous tissue-type plasminogen activator (tPA). METHODS: We tested remote ischemic perconditioning therapy (RIPerC) at 2 hours after embolic middle cerebral artery occlusion in the mouse with and without intravenous tPA at 4 hours. We assessed cerebral blood flow up to 6 hours, neurological deficits, injury size, and phosphorylation of Akt (Serine(473)) as a prosurvival signal in the ischemic hemisphere at 48 hours poststroke. RESULTS: RIPerC therapy alone improved the cerebral blood flow and neurological outcomes. tPA alone at 4 hours did not significantly improve the neurological outcome even after successful thrombolysis. Individual treatments with RIPerC and intravenous tPA reduced the infarct size (25.7% and 23.8%, respectively). Combination therapy of RIPerC and tPA resulted in additive effects in further improving the neurological outcome and reducing the infarct size (50%). All the therapeutic treatments upregulated phosphorylation of Akt in the ischemic hemisphere. CONCLUSIONS: RIPerC is effective alone after embolic middle cerebral artery occlusion and has additive effects in combination with intravenous tPA. RIPerC may be a simple, safe, and inexpensive combination therapy with intravenous tPA.

Oxidative stress contributes to sex differences in angiotensin II-mediated hypertension in spontaneously hypertensive rats.

NADPH oxidase has been implicated in ANG II-induced oxidative stress and hypertension in males; however, the contribution of oxidative stress to ANG II hypertension in females is unknown. In the present study, we tested the hypothesis that greater antioxidant capacity in female spontaneously hypertensive rats (SHR) blunts ANG II-induced oxidative stress and hypertension relative to males. Whole body and renal cortical oxidative stress levels were assessed in female and male SHR left untreated or following 2 wk of chronic ANG II infusion. Chronic ANG II infusion increased NADPH oxidase enzymatic activity in the renal cortex of both sexes; however, this increase only reached significance in female SHR. In contrast, male SHR demonstrated a greater increase in all measurements of reactive oxygen species production in response to chronic ANG II infusion. ANG II infusion increased plasma superoxide dismutase activity only in female SHR (76 ± 9 vs. 190 ± 7 Units·ml(-1)·mg(-1), P < 0.05); however, cortical antioxidant capacity was unchanged by ANG II in either sex. To assess the functional implication of alterations in NADPH enzymatic activity and oxidative stress levels following ANG II infusion, additional experiments assessed the ability of the in vivo antioxidant apocynin to modulate ANG II hypertension. Apocynin significantly blunted ANG II hypertension in male SHR (174 ± 2 vs. 151 ± 1 mmHg, P < 0.05), with no effect in females (160 ± 11 vs. 163 ± 10 mmHg). These data suggest that ANG II hypertension in male SHR is more dependent on increases in oxidative stress than in female SHR.

Neuroprotective effect of sesame seed oil in 6-hydroxydopamine induced neurotoxicity in mice model: cellular, biochemical and neurochemical evidence.

Natural antioxidants have shown a remarkable reduction in oxidative stress due to excess formation of reactive oxygen species by enhancing antioxidant mechanism in the neurodegenerative disorders. Sesame seed oil (SO) is one of the most important edible oil in India as well as in Asian countries and has potent antioxidant properties thus the present study evaluated the neuroprotective effect of SO by using 6-Hydroxydopamine (6-OHDA)-induced Parkinson's disease model in mice. The mice were fed an SO mix diet for 15 days and then 6-OHDA was injected into the right striatum of mice brain. Three weeks after 6-OHDA infusion, mice were sacrificed and the striatum was removed. The neuroprotective role of SO on the activities of antioxidant and non-antioxidant enzymes such as glutathione reductase (GR), glutathione-S-transferase (GST), glutathione peroxidase (GPx), catalase (CAT) and content of glutathione (GSH) and thiobarbituric acid reactive substance (TBARS) were studied in the striatum. The activities of all the above-mentioned enzymes decreased significantly in 6-OHDA group (Lesioned) when compared with Sham. The pretreatment of SO on antioxidant mechanism and dopamine level in the brain had shown some significant improvement in Lesion+SO (L+SO) group when compared with Lesioned group. However, NADPH oxidase subunit, Nox2 and inflammatory stimulator Cox2 expression was increased as well as antioxidant MnSOD level was decreased in Lesioned group while SO showed the inhibitory effect on the activation of Nox2 and Cox2 and restored MnSOD expression in L+SO group. Increased tyrosine hydroxylase (TH) expression in substantia nigra as well as dopamine and its metabolite DOPAC level in L+SO group also support our findings that SO may inhibit activation of NADPH oxidase dependent inflammatory mechanism due to 6-OHDA induced neurotoxicity in mice.

Complement C3a Receptor (C3aR) Mediates Vascular Dysfunction, Hippocampal Pathology, and Cognitive Impairment in a Mouse Model of VCID.

Vascular contributions to cognitive impairment and dementia (VCID) secondary to chronic mild-moderate cerebral ischemia underlie a significant percentage of cases of dementia. We previously reported that either genetic deficiency of the complement C3a receptor (C3aR) or its pharmacological inhibition protects against cerebral ischemia in rodents, while others have implicated C3aR in the pathogenesis seen in rodent transgenic models of Alzheimer's disease. In the present study, we evaluated the role of complement C3a-C3aR signaling in the onset and progression of VCID. We utilized the bilateral common carotid artery stenosis (BCAS) model to induce VCID in male C57BL/6 wild-type and C3aR-knockout (C3aR-/-) mice. Cerebral blood flow (CBF) changes, hippocampal atrophy (HA), white matter degeneration (WMD), and ventricular size were assessed at 4 months post-BCAS using laser speckle contrast analysis (LSCI) and magnetic resonance imaging (MRI). Cognitive function was evaluated using the Morris water maze (MWM), and novel object recognition (NOR), immunostaining, and western blot were performed to assess the effect of genetic C3aR deletion on post-VCID outcomes. BCAS resulted in decreased CBF and increased HA, WMD, and neurovascular inflammation in WT (C57BL/6) compared to C3aR-/- (C3aR-KO) mice. Moreover, C3aR-/- mice exhibited improved cognitive function on NOR and MWM relative to WT controls. We conclude that over-activation of the C3a/C3aR axis exacerbates neurovascular inflammation leading to poor VCID outcomes which are mitigated by C3aR deletion. Future studies are warranted to dissect the role of cell-specific C3aR in VCID.

Complement C3a receptor-mediated vascular dysfunction: a complex interplay between aging and neurodegeneration.

Vascular dysfunction resulting in compromised blood-brain barrier (BBB) integrity is evident in aging and disease. Although the complement C3a/C3a receptor (C3a/C3aR) axis influences normal brain aging and disease progression, the mechanisms governing endothelial C3aR-mediated neurovascular inflammation and BBB permeability remain unexplored. In this issue of the JCI, Propson et al. investigated endothelial C3a/C3aR signaling in normal, aged, and neurodegenerative mouse models. Endothelial C3aR signaling modulated age-dependent increases in VCAM1, initiated peripheral lymphocyte infiltration, and enhanced microglial activity. Increased calcium release downstream of C3aR signaling disrupted the vascular endothelial cadherin (VE-cadherin) junctions, increased BBB permeability, and degraded vascular structure and function. Mice lacking C3aR (C3ar1-/-) and mice treated with a C3aR antagonist showed attenuated age-related microglial reactivity and neurodegeneration. These results confirm that complement-mediated signaling impacts vascular health and BBB function in normal aging and neurodegenerative disease, suggesting that complement inhibitors represent a therapeutic option for cerebral microvascular dysfunction.

Remote Ischemic Post-Conditioning Therapy is Protective in Mouse Model of Traumatic Optic Neuropathy.

Traumatic optic neuropathy (TON) is characterized by visual dysfunction after indirect or direct injury to the optic nerve following blunt head trauma. TON is associated with increased oxidative stress and inflammation resulting in retinal ganglion cell (RGC) death. Remote ischemic post-conditioning (RIC) has been shown to enhance endogenous protective mechanisms in diverse disease models including stroke, vascular cognitive impairment (VCI), retinal injury and optic nerve injury. However, the protective mechanisms underlying the improvement of retinal function and RGC survival after RIC treatment remain unclear. Here, we hypothesized that RIC therapy may be protective following TON by preventing RGC death, oxidative insult and inflammation in the mouse retina. To carry out the study, mice were divided in three different groups (Control, TON and TON + RIC). We harvested retinal tissue 5 days after TON induction for western blotting and histochemical analysis. We observed increased TON-induced retinal cell death compared with controls by cleaved caspase-3 immunohistochemistry. Furthermore, the TON cohort demonstrated increased TUNEL positive cells which were significantly attenuated by RIC. Immunofluorescence data showed that oxidative stress markers dihydroethidium (DHE), NOX-2 and nitrotyrosine expression were elevated in the TON group relative to controls and RIC therapy significantly reduced the expression level of these markers. Next, we found that the proinflammatory cytokine TNF-α was increased and anti-inflammatory IL-10 was decreased in plasma of TON animals, and RIC therapy reversed this expression level. Interestingly, western blotting of retinal tissue showed that RGC marker Brn3a and tight junction proteins (ZO-1 and Occludin), and AMPKα1 expression were downregulated in the TON group compared to controls. However, RIC significantly increased the expression levels of these proteins. Together these data suggest that RIC therapy activates endogenous protective mechanisms which may attenuate TON-induced oxidative stress and inflammation, and improves BRB integrity.

C3a receptor antagonist therapy is protective with or without thrombolysis in murine thromboembolic stroke.

BACKGROUND AND PURPOSE: Intravenous thrombolysis (IVT) after stroke enhances C3a generation, which may abrogate the benefits of reperfusion. The C3aR antagonist SB290157 is neuroprotective following transient but not permanent middle cerebral artery occlusion (MCAo). SB290157 remains untested in thromboembolic (TE) models, which better approximate human stroke and also facilitate testing in combination with IVT. We hypothesized SB290157 would confer neuroprotection in TE stroke with and without "late" IVT. EXPERIMENTAL APPROACH: We used two different models of TE stroke to examine the efficacy of SB290157 alone and in combination with late IVT. We evaluated the benefit of SB290157 in attenuating post-ischaemic behavioural deficits, infarction, brain oedema and haemorrhage. KEY RESULTS: Plasma C3a was elevated 6 hr after TE stroke alongside increased cerebrovascular C3aR expression, which was sustained to 4 weeks. Increased C3aR expression also was visualized in human ischaemic brain. In a photothrombotic (PT) stroke model, which exhibits rapid spontaneous reperfusion, SB290157 given at 1 hr post-PT significantly improved neurofunction and reduced infarction at 48 hr. In an embolic (eMCAo) model, SB290157 administered at 2 hr improved histological and functional outcomes. Conversely, late IVT administered 4.5 hr post-eMCAo was ineffective likely due to increased haemorrhage and brain oedema. However, SB290157 administered prior to late IVT ameliorated haemorrhage and oedema and improved outcomes. CONCLUSIONS AND IMPLICATIONS: We conclude that SB290157 is safe and effective with and without late IVT following TE stroke. Therefore, C3a receptor antagonist therapy represents a promising candidate for clinical translation in stroke, particularly as an adjuvant to IVT.

Iron deficiency augments bisphenol A-induced oxidative stress in rats.

Bisphenol A (BPA), an estrogenic environmental contaminant is also known for oxidative stress-inducing effect. Malnutrition is recognized as a confounding factor in oxidative stress. However, little is known about effect of malnutrition on oxidative stress induced by BPA or other endocrine disrupting chemicals (EDCs). We studied effect of malnutrition (iron deficiency) in rats chronically exposed to low levels of BPA taking into consideration the oxidative stress and antioxidant status in liver, kidney and gonads. Iron deficiency significantly elevated level of lipid peroxidation in BPA-exposed rats. Similarly, decrease in reduced glutathione level was more significant in rats maintained on iron deficient diet compared to those maintained on normal diet. Iron deficiency also significantly modulated activities of vital antioxidant enzymes in all the tissues. Female rats showed more vulnerability than males to iron-deficiency modulated effects of BPA on the above parameters. This study demonstrated that malnutrition, especially iron deficiency, might act as a confounding factor in EDC-induced oxidative stress. However, more studies may be needed to confirm effect of nutritional factors on estrogenic activity of BPA or other EDCs.

The Role of Complement C3a Receptor in Stroke.

The complement system is a key regulator of the innate immune response against diseased tissue that functions across multiple organ systems. Dysregulation of complement contributes to the pathogenesis of a number of neurological diseases including stroke. The C3a anaphylatoxin, via its cognate C3a receptor (C3aR), mediates inflammation by promoting breakdown of the blood-brain barrier and the massive infiltration of leukocytes into ischemic brain in experimental stroke models. Studies utilizing complement deficient mice as well as pharmacologic C3aR antagonists have shown a reduction in tissue injury and mortality in murine stroke models. The development of tissue-specific C3aR knockout mice and more specific C3aR antagonists is warranted to facilitate our understanding of the role of the C3aR in brain ischemia with the ultimate goal of clinical translation of therapies targeting C3aR in stroke patients.

Acetyl-11-keto-ß-boswellic acid (AKBA) Attenuates Oxidative Stress, Inflammation, Complement Activation and Cell Death in Brain Endothelial Cells Following OGD/Reperfusion.

Brain endothelial cells play an important role in maintaining blood flow homeostasis in the brain. Cerebral ischemia is a major cause of endothelial dysfunction which can disrupt the blood-brain barrier (BBB). Oxygen-glucose deprivation (OGD)/reperfusion promote cell death and BBB breakdown in brain endothelial cells. Acetyl-11-keto-ß-boswellic acid (AKBA), a biologically active phytoconstituent of the medicinal plant Boswellia serrata, has been shown to be protective against various inflammatory diseases as well as ischemic brain injury. The molecular mechanisms underlying these beneficial characteristics of AKBA are poorly understood. We subjected bEND.3 cells to OGD/reperfusion to investigate the protective role of AKBA in this model. We found that AKBA treatment attenuated endothelial cell death and oxidative stress assessed by means of TUNEL assay, cleaved-caspase-3, and dihydroethidium (DHE) staining. Furthermore, OGD downregulated tight junction proteins ZO-1 and Occludin levels, and increased the expressions of inflammatory cytokines TNF-α, ICAM-1, and complement C3a receptor (C3aR). We also noticed the increased phosphorylation of ERK 1/2 in bEND.3 cells in OGD group. AKBA treatment significantly attenuated expression levels of these inflammatory proteins and prevented the degradation of ZO-1 and Occludin following OGD. In conclusion, AKBA treatment provides protection against endothelial cell dysfunction following OGD by attenuating oxidative stress and inflammation.

C3a Receptor Inhibition Protects Brain Endothelial Cells Against Oxygen-glucose Deprivation/Reperfusion.

The complement cascade is a central component of innate immunity which plays a critical role in brain inflammation. Complement C3a receptor (C3aR) is a key mediator of post-ischemic cerebral injury, and pharmacological antagonism of the C3a receptor is neuroprotective in stroke. Cerebral ischemia injures brain endothelial cells, causing blood brain barrier (BBB) disruption which further exacerbates ischemic neuronal injury. In this study, we used an in vitro model of ischemia (oxygen glucose deprivation; OGD) to investigate the protective effect of a C3aR antagonist (C3aRA, SB290157) on brain endothelial cells (bEnd.3). Following 24 hours of reperfusion, OGD-induced cell death was assessed by TUNEL and Caspase-3 staining. Western blot and immunocytochemistry were utilized to demonstrate that OGD upregulates inflammatory, oxidative stress and antioxidant markers (ICAM-1, Cox-2, Nox-2 and MnSOD) in endothelial cells and that C3aRA treatment significantly attenuate these markers. We also found that C3aRA administration restored the expression level of the tight junction protein occludin in endothelial cells following OGD. Interestingly, OGD/reperfusion injury increased the phosphorylation of ERK1/2 and C3aR inhibition significantly reduced the activation of ERK suggesting that endothelial C3aR may act via ERK signaling. Furthermore, exogenous C3a administration stimulates these same inflammatory mechanisms both with and without OGD, and C3aRA suppresses these C3a-mediated responses, supporting an antagonist role for C3aRA. Based on these results, we conclude that C3aRA administration attenuates inflammation, oxidative stress, ERK activation, and protects brain endothelial cells following experimental brain ischemia.

Topically applied vitamin E prevents massive cutaneous inflammatory and oxidative stress responses induced by double application of 12-O-tetradecanoylphorbol-13-acetate (TPA) in mice.

Vitamin E (alpha-tocopherol) is a promising chemopreventive and pharmacologically safe agent, which can be exploited or tested against skin cancer. It is an established antioxidant with an ability to ameliorate the UV-induced skin damage and chemically induced inflammation in lungs. However, there are some conflicting reports about its role as a modulator of chemically induced promotion. We evaluated its efficacy in preventing the inflammatory and oxidative stress responses in a double 12-O-tetradecanoylphorbol-13-acetate (TPA) application tumor skin promotion protocol. Double application of TPA was undertaken to produce massive inflammatory and oxidative stress responses. Topical TPA treatment adversely altered many of the marker responses of stage I skin tumor promotion. Vitamin E application 30 min prior to TPA treatment (10 nmol) inhibited induction of hydrogen peroxide, myeloperoxidase (MPO) activity, xanthine oxidase (XO) activity and lipid peroxidation (LPO). Vitamin E also positively modulated altered antioxidants of mouse skin. Histological examination also revealed marked improvement. These results confirm the efficacy of vitamin E against early inflammatory and oxidative stress responses, which are hallmark of tumor promotion and provide rational basis for chemopreventive action of vitamin E in skin cancer.

Protective effect of S-allylcysteine against cyclophosphamide-induced bladder hemorrhagic cystitis in mice.

S-Allylcysteine (SAC), an organosulfur compound of aged garlic extract (AGE) regulates the thiol status of the cell and scavenges free radicals. Depletion of thiols along with free radical generation has been implicated in cyclophosphamide (CP)-induced urotoxicity. We studied modulatory effect of SAC on CP-induced urotoxicity in mice focusing on hemorrhagic cystitis (HC). SAC (150 and 300 mg kg(-1)) was administered in CP treated animals (200 mg kg(-1)) and bladder was observed for histological and biochemical changes. CP treatment caused a marked increase in the lumen exudates, edema, vasodilation and HC in lamina propia in the bladder. These changes were accompanied by increase in lipid peroxidation (LPO), and decrease in reduced glutathione (GSH) and activities of antioxidant enzymes. SAC not only showed protection in tissue histology but also improved the decreased activities of antioxidant enzymes. SAC treatment also reduced LPO and increased GSH levels. Although SAC treatment did not ensure full recovery, the marked improvement in histology and antioxidants of bladder suggests that it has a significant modulatory effect on CP-induced urotoxicity. Since decrease in antioxidant level is the major cause of CP urotoxicity, the protective effect of SAC deserves its further exploration involving laboratory and clinical investigations.

Pro-apoptotic effect of fly ash leachates in hepatocytes of freshwater fish (Channa punctata Bloch).

The pro-apoptotic effect of fly ash leachates (FAL) was studied in the hepatocytes of an Indian freshwater fish, Channa punctata Bloch. Hepatocytes were exposed to different concentrations of '7-day' FAL for 24 and 48h and various parameters of apoptosis were studied using standardized procedures. FAL-induced apoptosis in hepatocytes was indicated by cytological examination, DNA fragmentation and DNA laddering. The induction in cytochrome-c release, caspases 3, 7, 10 and 9 activities and lactate dehydrogenase level provide mechanistic platform for FAL-induced apoptosis. Cytological examination showed an unambiguous apoptotic effect of ash leachates in fish hepatocytes. Exposed hepatocytes also showed increased production of H(2)O(2), superoxide ions and an increase in lipid peroxidation (LPO). The present study suggests a possible role of reactive oxygen species (ROS) in FAL-induced apoptosis in hepatocytes. Lactate dehydrogenase, LPO and apoptosis as biomarkers of cytotoxicity have recently been used for assessment of ecotoxicological impact of environmental chemicals. Our findings show that these biomarkers may also be used for evaluation of ecotoxicological impact of complex chemical mixture such as fly ash and its leachates.

Deregulation of ZPR1 causes respiratory failure in spinal muscular atrophy.

Spinal muscular atrophy (SMA) is caused by the low levels of survival motor neuron (SMN) protein and is characterized by motor neuron degeneration and muscle atrophy. Respiratory failure causes death in SMA but the underlying molecular mechanism is unknown. The zinc finger protein ZPR1 interacts with SMN. ZPR1 is down regulated in SMA patients. We report that ZPR1 functions downstream of SMN to regulate HoxA5 levels in phrenic motor neurons that control respiration. Spatiotemporal inactivation of Zpr1 gene in motor neurons down-regulates HoxA5 and causes defects in the function of phrenic motor neurons that results in respiratory failure and perinatal lethality in mice. Modulation in ZPR1 levels directly correlates and influences levels of HoxA5 transcription. In SMA mice, SMN-deficiency causes down-regulation of ZPR1 and HoxA5 that result in degeneration of phrenic motor neurons. Identification of ZPR1 and HoxA5 as potential targets provides a paradigm for developing strategies to treat respiratory distress in SMA.

The modulatory effect of deltamethrin on antioxidants in mice.

BACKGROUND: Deltamethrin is a alpha-cyano pyrethroid insecticide used extensively in pest control. Although initially thought to be least toxic, a number of recent reports showed its toxicity in mammalian and non-mammalian laboratory and wildlife animal species. In fish, it is a potent oxidative stress-inducing agent. We studied the oxidative stress-inducing effect of deltamethrin in mice. METHODS: Male Swiss albino mice were orally administered 2 doses of deltamethrin viz., 5.6 and 18mg/kg body weight (bw), for 15 days. RESULTS: Both the doses of deltamethrin significantly induced lipid peroxidation (LPO) in liver and kidney. Along with the induction of LPO, activities of vital antioxidant enzymes such as glutathione peroxidase (GPx), glutathione S-transferase (GST) and catalase (CAT) were also suppressed in both the tissues. Glutathione (GSH) level was also decreased. GSH decrease was more pronounced in kidney than the liver. CONCLUSION: Toxicity of many chlorinated and organophosphate insecticides is mediated by the reactive oxygen species (ROS). Findings of the present investigation also suggest a role for ROS in deltamethrin toxicity. An increased LPO indicates that these ROS might have caused degradation of biomembrane in deltamethrin-exposed animals.