SOD1 down-regulates NF-kappaB and c-Myc expression in mice after transient focal cerebral ischemia.
ABSTRACT Reactive oxygen species (ROS) are implicated in reperfusion injury after focal cerebral ischemia (FCI). Reactive oxygen species regulate activity of transcription factors like NF-kappaB. The authors investigated the role of ROS in NF-kappaB activity after FCI using transgenic mice that overexpressed human copper/zinc-superoxide dismutase (SOD1) and that had reduced infarction volume after FCI. Superoxide dismutase transgenic and wild-type mice were subjected to 1 hour of middle cerebral artery occlusion (MCAO) and subsequent reperfusion. Immunohistochemistry showed SOD1 overexpression attenuated ischemia-induced NF-kappaB p65 immunoreactivity. Colocalization of NF-kappaB and the neuronal marker, microtubule-associated proteins (MAPs), showed that NF-kappaB was up-regulated in neurons after FCI. Electrophoretic mobility shift assays showed that SODI overexpression reduced ischemia-induced NF-kappaB DNA binding activity. Supershift assays showed that DNA-protein complexes contained p65 and p50 subunits. Immunoreactivity of c-myc, an NF-kappaB downstream gene, was increased in the ischemic cortex and colocalized with NF-kappaB. Western blotting showed that SOD1 overexpression reduced NF-kappaB and c-Myc protein levels in the ischemic brain. Colocalization of c-Myc and TUNEL staining was observed 24 hours after FCI. The current findings provide the first evidence that SOD1 overexpression attenuates activation of NF-kappaB after transient FCI in mice and that preventing this early activation may block expression of downstream deleterious genes like c-myc, thereby reducing ischemic damage.
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ABSTRACT: This study was conducted to investigate the role of stromal-derived factor-1 alpha (SDF-1α) in a secondary brain injury after traumatic brain injury (TBI) in rats, and to further elucidate its underlying regulatory mechanisms. Male Sprague-Dawley rats underwent TBI for 30 min, and then received intracranial injections of recombinant SDF-1α, SDF-1α antibody, or saline as a vehicle control. At 24 h after TBI, brain tissues from the experimental animals were subjected to histology, immunohistochemistry, quantitative real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and western blot analyses. TBI-induced brain edema and blood-brain barrier disruption were ameliorated by post-injury injections of SDF-1α. TBI-induced neuronal degradation and apoptosis, accompanied by increased cleaved caspase-3, cleaved PARP and Bax, and decreased Bcl-2 were found to be attenuated by SDF-1α injection. Nitric oxide (NO) and inducible nitric oxide synthase (iNOS) levels decreased in SDF-1α treated animals after TBI. SDF-1α repressed inflammatory responses by inhibiting the expression of pro-inflammatory cytokines, such as TNF-α, IL-1β, and IL-6. However, neutralizing the effect of SDF-1α with its antibody abolished these therapeutic alterations in TBI animals. Importantly, SDF-1α attenuated the brain lesion by affecting the ERK and NF-κB signaling pathways after mechanical head trauma in rats. SDF-1α ameliorates mechanical trauma-induced pathological changes via its anti-apoptotic and anti-inflammatory action in the brain.Agents and Actions 12/2013; · 1.59 Impact Factor
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ABSTRACT: Hypertension induces end-organ damage through inflammation, and autophagy plays a crucial role in the regulation of cellular homeostasis. In the present study, we aimed to define the role of autophagy in the development of inflammation and cardiac injury induced by angiotensin II (Ang II). Autophagy protein 5 (Atg5) haplodeficiency (Atg5(+/-)) and age-matched wild-type (WT) C57BL/6J mice were infused with Ang II (1500ng/kg/min) or saline for 7 days. Heart sections were stained with hematoxylin and eosin (H&E), Masson's trichrome, and immunohistochemical stains. Cytokine and LC3 levels were measured using real-time PCR or western blot analysis. After Ang II infusion, the WT mice exhibited marked macrophage accumulation, cytokine expression, and reactive oxygen species (ROS) production compared with saline-infused controls. However, these effects induced by Ang II infusion were aggravated in Atg5(+/-) mice. These effects were associated with Atg5-mediated impaired autophagy, accompanied by increased production of ROS and activation of nuclear factor- κB (NF-κB) in macrophages. Finally, increased cardiac inflammation in Atg5 haplodeficient mice was associated with increased cardiac fibrosis. Atg5 deficiency-mediated autophagy increases ROS production and NF-κB activity in macrophages, thereby contributing to cardiac inflammation and injury. Thus, improving autophagy may be a novel therapeutic strategy to ameliorate hypertension-induced inflammation and organ damage.Free radical biology & medicine 01/2014; · 5.42 Impact Factor
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ABSTRACT: Cerebral ischemia initiates a cascade of detrimental events including glutamate-associated excitotoxicity, intracellular calcium accumulation, formation of Reactive oxygen species (ROS), membrane lipid degradation, and DNA damage, which lead to the disruption of cellular homeostasis and structural damage of ischemic brain tissue. Cerebral ischemia also triggers acute inflammation, which exacerbates primary brain damage. Therefore, reducing oxidative stress (OS) and downregulating the inflammatory response are options that merit consideration as potential therapeutic targets for ischemic stroke. Consequently, agents capable of modulating both elements will constitute promising therapeutic solutions because clinically effective neuroprotectants have not yet been discovered and no specific therapy for stroke is available to date. Because of their ability to modulate both oxidative stress and the inflammatory response, much attention has been focused on the role of nitric oxide donors (NOD) as neuroprotective agents in the pathophysiology of cerebral ischemia-reperfusion injury. Given their short therapeutic window, NOD appears to be appropriate for use during neurosurgical procedures involving transient arterial occlusions, or in very early treatment of acute ischemic stroke, and also possibly as complementary treatment for neurodegenerative diseases such as Parkinson or Alzheimer, where oxidative stress is an important promoter of damage. In the present paper, we focus on the role of NOD as possible neuroprotective therapeutic agents for ischemia/reperfusion treatment.Oxidative Medicine and Cellular Longevity 01/2013; 2013:297357.