Innate and adaptive immune gene expression in the brain is associated with neuropathological changes after infection with bovine alpha-herpesvirus-5 in mice.

Bovine alpha herpesvirus-5 (BoAHV-5) is related to the development of meningoencephalitis in cattle. Very little is known about the molecular pathways involved in the central nervous system (CNS) damage associated with inflammation during BoHV-5 infection in mice. To better identify the specific immunological pathways triggered by BoAHV-5 infection in mice, we evaluated the mRNA expression of 84 genes involved in innate and adaptive immune responses. We compared gene expression changes in the cerebrum from noninfected and infected mice with BoHV-5 at a 1 × 107 TCID50. Then, we analyzed the association of these genes with neurological signs, neuropathology, and activation of glial cells in response to BoHV-5 infection. Three days after BoAHV-5 infection, increased expression of TNF, IL-2, CXCL10, CXCR3, CCR4, CCL5, IFN-γ, IL-10, IRF7, STAT1, MX1, GATA 3 C3, LIZ2, caspase-1 and IL-1b was found. We also observed the upregulated expression of the CD8a, TBX21 and CD40LG genes and the downregulated expression of the CD4 gene after BoAHV-5 infection. In addition, BoHV-5-infected animals showed higher levels of all the evaluated inflammatory mediators (TNF, IFN-γ and IL-10) on day 3 postinfection. BoAHV-5-infected animals showed neurological changes along with meningoencephalitis, neuropil vacuolation, hemorrhage and reactive gliosis. Astrogliosis and microgliosis, indicated by increased expression of glial fibrillary acidic protein (GFAP) and ionized calcium-binding adapter molecule 1 (Iba-1), were found throughout the neuropil in infected brains. Moreover, cleaved caspase-3 immunopositive glio-inflammatory cells were visualized around some blood vessels in areas of neuroinflammation in the cerebrum. In agreement on that we found higher cleaved caspase-3 and Iba-1 expression evaluated by western blot analysis in the brains of infected mice compared to control mice. In conclusion, our results revealed.

Brain-derived neurotrophic factor is down regulated after bovine alpha-herpesvirus 5 infection in both wild-type and TLR3/7/9 deficient mice.

Neurotrophic factors have been implicated in the control of neuronal survival and plasticity in different brain diseases. Meningoencephalitis caused by bovine alpha-herpesvirus 5 (BoHV-5) infection is a frequent neurological disease of young cattle, being the involvement of apoptosis in the development of neuropathological changes frequently discussed in the literature. It's well known that Toll-like receptors (TLRs) can activate neuroinflammatory response and consequently lead to neuronal loss. However, there are no studies evaluating the expression of neurotrophic factors and their association with brain pathology and TLRs during the infection by BoHV-5. The current study aimed to analyze brain levels of neurotrophic factors along with neuropathological changes during acute infection by BoHV-5 in wild-type (WT) and TLR3/7/9 (TLR3/7/9-/-) deficiency mice. The infection was induced by intracranial inoculation of 1 × 104 TCID50 of BoHV-5. Infected animals presented similar degrees of clinical signs and neuropathological changes. Both infected groups had meningoencephalitis and neuronal damage in CA regions from hippocampus. BoHV-5 infection promoted the proliferation of Iba-1 positive cells throughout the neuropil, mainly located in the frontal cortex. Moreover, significant lower levels of brain-derived neurotrophic factor (BDNF) were detected in both BoHV-5 infected WT and TLR3/7/9 deficient mice, compared with non-infected animals. Our study showed that BDNF down regulation was associated with brain inflammation, reactive microgliosis and neuronal loss after bovine alpha-herpesvirus 5 infection in mice. Moreover, we demonstrated that combined TLR3/7/9 deficiency does not alter those parameters.

Minocycline treatment prevents depression and anxiety-like behaviors and promotes neuroprotection after experimental ischemic stroke.

Depression and anxiety have been reported as the major neuropsychiatric consequences following stroke. Minocycline, a neuroprotective drug has minimized depressive symptoms in patients with major depressive disorders and anxiety-like symptoms. In addition, minocycline demonstrated efficacy and seemed a promising neuroprotective agent in acute stroke patients. The present studied evaluated the effects of minocycline treatment on the depression and anxiety-like behaviors, brain damage and expression of inflammatory and neuroprotective mediators after transient global cerebral ischemia in C57BL/6 mice. Brain ischemia was induced by bilateral occlusion of the common carotids (BCCAo) for 25 min and subsequent reperfusion. Sham and BCCAo animals received minocycline at a dose of 30 mg/kg by intraperitoneal injection during 14 days. The locomotor activity, depression and anxiety-like behaviors were assessed by open field, forced swim and elevated plus maze tests, respectively. Then, the brains were removed and processed to evaluate brain damage by histological and morphometric analysis, hippocampal neurodegeneration using Fluoro-Jade C histochemistry, microglial activity using iba-1 immunohistochemistry, brain levels of TNF, IFN-γ, IL-6, IL-10, IL-12p70 and CCL2 by CBA, CX3CL1 and BDNF by ELISA assays. The animals developed depression and anxiety-like behaviors post-stroke and minocycline treatment prevented those neurobehavioral changes. Moreover, minocycline-treated BCCAo animals showed less intense brain damage in the cerebral cortex, brainstem and cerebellum as well as significantly reduced hippocampal neurodegeneration. BCCAo groups exhibited up-regulation of some cytokines at day 14 after ischemia and brain levels of CX3CL1 and BDNF remained unaltered. Our data indicate that the depression and anxiety-like behavioral improvements promoted by minocycline treatment might be related to its neuroprotective effect after brain ischemia in mice.

Knockdown of C-C Chemokine Receptor 5 (CCR5) is Protective Against Cerebral Ischemia and Reperfusion Injury.

BACKGROUND: Stroke is the second leading cause of death and a major cause of disability of adults worldwide. Inflammatory processes are known to contribute to the pathophysiology of cerebral ischemia, especially following reperfusion. Chemokines and their receptors are involved in migration of leukocytes and have been implicated in the pathogenesis of ischemic stroke. OBJECTIVE: In the present study, we investigated the effects of C-C chemokine receptor type 5 (CCR5) deficiency on neurological outcome, brain damage and expression of pro-inflammatory chemokines: chemokine (C-X-C motif) ligand 1 (CXCL1), chemokine (CC motif) ligand 3 (CCL3) and chemokine (C-C motif) ligand 5 (CCL5), and the brain-derived neurotrophic factor (BDNF). METHODS: Adult male C57BL/6 (wild-type) (WT) and CCR5 deficient mice were subjected to transient cerebral ischemia induced by 25 min of bilateral common carotid artery occlusion (BCCAO) followed by 24 hours of reperfusion. Mice were divided into four groups: WT sham group, which underwent sham operation; WT ischemic group, which was subjected to transient bilateral common carotid artery occlusion, CCR5-/- sham group, which underwent sham operation, and CCR5-/- ischemic group, which was subjected to transient BCCAO. RESULTS: In CCR5 deficiency, we observed a significant improvement in the neurological deficits associated with decreased brain infarcted area as evaluated by triphenyltetrazolium chloride (TTC). Moreover, CCR5 deficiency revealed decreased percentage of necrotic cavities areas and frequency of ischemic neurons by histometric analysis. In addition, CCR5-/- ischemic animals showed lower brain levels of the chemokine CXCL1 and higher levels of BDNF by ELISA, compared with WT BCCAo mice. CONCLUSION: Taken together, our results suggest a potential neuroprotection in the absence of CCR5 receptor during global brain ischemia and reperfusion injury.

Role of the suppressor of cytokine signaling 2 (SOCS2) during meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5).

The role of suppressors of cytokine signaling (SOCS) in meningoencephalitis caused by Bovine herpesvirus 5 (BoHV-5) was evaluated by intracranial infection in C57BL/6 wild-type mice (WT) and SOCS2 deficient mice (SOCS2(-/-)). Both infected groups presented weight loss, ruffled fur and hunched posture. Additionally, infected SOCS2(-/-) mice showed swollen chamfer and progressive depression. Infected WT animals developed mild meningitis, characterized by infiltration of mononuclear cells. Moreover, viral DNA was detected in liver and lung from infected WT group. This group also showed elevated brain levels of IFN-γ, IL-10, CXCL1 and CCL5, when compared with non-infected WT animals. Brain inflammation was exacerbated in infected SOCS2(-/-) mice with widespread distribution of the virus and increased brain levels of TNF-α, IFN-γ, IL-10, IL-12, CXCL1 and CCL5, when compared with WT infected mice. Moreover, infected SOCS2 deficient mice exhibited reduced brain mRNA expression of IFNα and IFNß and increased expression of mRNA of SOCS1, compared with infected WT mice. Taken together, our study provides an insight into the role of SOCS2 in modulating the immune response to BoHV-5 infection.

Platelet-activating factor receptor (PAFR) plays a crucial role in experimental global cerebral ischemia and reperfusion.

Stroke is one of the most frequent causes of death and disability worldwide leading to a significant clinical and socioeconomic burden. Although different mechanisms are involved in the pathogenesis of stroke, inflammatory response occurs after ischemia and contributes to the expansion of brain injury. Platelet-activating factor receptor (PAF) plays crucial roles in both physiological and pathological conditions in the brain. PAF receptor (PAFR) may be expressed on cellular and nuclear membranes of various cell types, especially leukocytes, platelets, endothelial cells, neuronal cells and microglia. Herein, using mice lacking the PAFR receptor (PAFR(-/-)), we investigate a potential role for this receptor during experimental transient global cerebral ischemia and reperfusion (BCCAo). In PAFR deficiency, we observed a significant improvement in the neurological deficits, which were associated with a reduction of brain infarcted area as evaluated by triphenyltetrazolium chloride (TTC). Moreover, a decrease in the percentage of necrotic cavities areas and in the frequency of ischemic neurons was also found by employing histometric analysis. In addition, in PAFR(-/-) mice there was prevention of caspase-3 activation and decreased vascular permeability and brain edema. Decreased brain levels of the cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta) and the chemokine (C-X-C motif) ligand 1 (CXCL1) by ELISA were also detected in PAFR(-/-) BCCAo animals. Taken together, our results suggest that PAFR activation might be crucial for the global brain ischemia and reperfusion injury.