Role of PGE2 EP1 Receptor in Intracerebral Hemorrhage-Induced Brain Injury

Prostaglandin E₂ (PGE₂) has been described to exert beneficial and detrimental effects in various neurologic disorders. These conflicting roles of PGE₂ could be attributed to its diverse receptor subtypes, EP1–EP4. At present, the precise role of EP1 in intracerebral hemorrhage (ICH) is unknown. Therefore, to elucidate its possible role in ICH, intrastriatal injection of collagenase was given in randomized groups of adult male wildtype (WT) and EP1 receptor knockout (EP1^?/?) C57BL/6 mice. Functional outcomes including neurologic deficits, rotarod performance, open field activity, and adhesive removal performance were evaluated at 24, 48, and 72 h post-ICH. Lesion volume, cell survival and death, were assessed using Cresyl Violet, and Fluoro-Jade staining, respectively. Microglial activation and phagocytosis were estimated using Iba1 immunoreactivity and fluorescently-labeled microspheres. Following 72 h post-ICH, EP1^?/? mice showed deteriorated outcomes compared to the WT control mice. These outcomes were demonstrated by elevated neurological deficits, exacerbated lesion volume, and significantly worsened sensorimotor functions. Fluoro-Jade staining showed significantly increased numbers of degenerating neurons and reduced neuronal survival in EP1^?/? compared to WT mice. To assess in vivo phagocytosis, the number of microspheres phagocytosed by Iba1-positive cells was 145.4 ± 15.4 % greater in WT compared to EP1^?/? mice. These data demonstrate that EP1 deletion exacerbates neuro-behavioral impairments following ICH, potentially by slowing down/impairing microglial phagocytosis. A better understanding of this EP1 mechanism could lead to improved intervention strategies for hemorrhagic stroke.     

A novel RORγt inhibitor is a potential therapeutic agent for the topical treatment of psoriasis with low risk of thymic aberrations

Background

Retinoic acid receptor-related orphan receptor gamma t (RORγt) has critical roles in the development, maintenance and function of interleukin (IL)-17-producing cells and is a highly attractive target for the treatment of IL-17-mediated autoimmune disease, particularly psoriasis. On the other hand, RORγt is also critical for controlling apoptosis during thymopoiesis, and genetic RORγt ablation or systematic RORγt inhibition cause progressive thymic aberrations leading to T cell lymphomas.

Molecular mechanisms regulating NLRP3 inflammasome activation

Inflammasomes are multi-protein signaling complexes that trigger the activation of inflammatory caspases and the maturation of interleukin-1β. Among various inflammasome complexes, the NLRP3 inflammasome is best characterized and has been linked with various human autoinflammatory and autoimmune diseases. Thus, the NLRP3 inflammasome may be a promising target for anti-inflammatory therapies. In this review, we summarize the current understanding of the mechanisms by which the NLRP3 inflammasome is activated in the cytosol. We also describe the binding partners of NLRP3 inflammasome complexes activating or inhibiting the inflammasome assembly. Our knowledge of the mechanisms regulating NLRP3 inflammasome signaling and how these influence inflammatory responses offers further insight into potential therapeutic strategies to treat inflammatory diseases associated with dysregulation of the NLRP3 inflammasome.     

The Effects of Olmesartan and Alfacalcidol on Renoprotection and klotho Gene Expression in 5/6 Nephrectomized Spontaneously Hypertensive Rats

Recently, an angiotensin inhibitor has been shown to upregulate the klotho mRNA level in chronic renal failure. In addition, the administration of vitamin D has been reported to improve the mortality of patients with chronic renal failure. In this study, we examined the effects of an angiotensin inhibitor and/or vitamin D on the progression of chronic renal failure by using male 5/6 nephrectomized (5/6Nx) spontaneously hypertensive rats. Male 5/6Nx spontaneously hypertensive rats were assigned to 4 groups as follows: 5/6Nx group, 5/6Nx rats; Alf group, 5/6Nx rats administered alfacalcidol (0.2 μg/kg/day); Olm group, 5/6Nx rats administered olmesartan (15 mg/kg/day); Alf + Olm group, 5/6Nx rats administered alfacalcidol (0.2 μg/kg/day) and olmesartan (15 mg/kg/day). These drugs were administered for 12 weeks. Systolic blood pressure in the Alf, Olm and Alf + Olm groups were significantly decreased relative to that in the 5/6Nx group during the 12-week experimental period. As a result, all treated groups showed renoprotection based on improvement of the systolic blood pressure, urinary protein excretion and histological renal fibrosis. Combination therapy of alfacalcidol and olmesartan was more effective than either alfacalcidol or olmesartan alone. Expression of klotho mRNA was significantly upregulated in the Alf + Olm group in comparison with in the 5/6Nx group. Serum levels of fibroblast growth factor 23 in the Alf group and the Alf + Olm group were significantly higher than those in the 5/6Nx group and the Olm group. In conclusion, the combination of Olm and Alf inhibited the progression of renal damage in the 5/6Nx group through the strong antihypertensive effect as well as the upregulation of the klotho gene.