purmorphamine and Inflammation

In Parkinson's disease (PD), microglial activation-mediated neuroinflammation is associated with dopaminergic neurons degeneration in the substantia nigra pars compacta. Previous studies that have investigated this neurodegenerative disease have reported that the Sonic hedgehog (SHH) signaling pathway, through inhibiting the inflammatory processes, exerts a beneficial neuroprotective effect. However, the mechanisms underlying the anti‑inflammatory and neuroprotective effects of this signaling pathway remain poorly understood. The present study aimed to further investigate these mechanisms in vitro and in vivo. At first, BV2 microglial cells treated with lipopolysaccharide (LPS) were used to induce an inflammatory response. It was observed that the activation of SHH signaling by Purmorphamine attenuated the LPS‑induced inflammatory response, increased the expression of transforming growth factor‑β1 through the phosphatidylinositol 3‑kinase (PI3K)/AKT serine/threonine kinase (Akt) intracellular signaling pathway and inhibited nuclear receptor subfamily 4 group A member 2, independently of the PI3K/Akt signaling pathway. Furthermore, the blockade of the PI3K/Akt signaling pathway by intranasal administration of LY294002, significantly reduced the SHH‑associated neuroprotective effects on dopaminergic neurons, improved motor functions, and increased the microglial activation and inflammatory response in a mouse model of PD induced using 1‑methyl‑4‑phenyl‑1,2,3,6‑tetrahydropyridine. In conclusion, the data of the present study reported that anti‑inflammatory and neuroprotective effects can be obtained in BV2 microglial cells and in a mouse model of PD by successive activation of the SHH and PI3K/Akt signaling pathways.

Topics: Animals; Cell Line; Disease Models, Animal; Dopaminergic Neurons; Hedgehog Proteins; Inflammation; Male; Mice; Microglia; Morpholines; Neuroprotective Agents; Parkinson Disease; Phosphatidylinositol 3-Kinase; Proto-Oncogene Proteins c-akt; Purines; Signal Transduction

Ischemic stroke occurs as a result of blood supply interruption to the brain causing tissue degeneration, patient disabilities or death. Currently, treatment of ischemic stroke is limited to thrombolytic therapy with a narrow time window of administration. The sonic hedgehog (Shh) signaling pathway has a fundamental role in the central nervous system development, but its impact on neural cell survival and tissue regeneration/repair after ischemic stroke has not been well investigated. Here we report the neuroprotective properties of a small-molecule agonist of the Shh co-receptor Smoothened, purmorphamine (PUR), in the middle cerebral artery occlusion model of ischemic stroke. We found that intravenous administration of PUR at 6 h after injury was neuroprotective and restored neurological deficit after stroke. PUR promoted a transient upregulation of tissue-type plasminogen activator in injured neurons, which was associated with a reduction of apoptotic cell death in the ischemic cortex. We also observed a decrease in blood-brain barrier permeability after PUR treatment. At 14 d postinjury, attenuation of inflammation and reactive astrogliosis was found in PUR-treated animals. PUR increased the number of newly generated neurons in the peri-infarct and infarct area and promoted neovascularization in the ischemic zone. Notably, PUR treatment did not significantly alter the ischemia-induced level of Gli1, a Shh target gene of tumorigenic potential. Thus our study reports a novel pharmacological approach for postischemic treatment using a small-molecule Shh agonist, providing new insights into hedgehog signaling-mediated mechanisms of neuroprotection and regeneration after stroke.

Topics: Animals; Apoptosis; Brain Ischemia; Cerebral Cortex; Disease Models, Animal; Hedgehog Proteins; Inflammation; Male; Mice, Inbred C57BL; Morpholines; Nerve Regeneration; Neurons; Neuroprotective Agents; Purines; Receptors, G-Protein-Coupled; Signal Transduction; Smoothened Receptor; Stroke; Time Factors; Tissue Plasminogen Activator; Up-Regulation