The phosphoinositide-3 kinase signaling is involved in neuroinflammation in hypertensive rats.

AIMS: It has been demonstrated that neuroinflammation is associated with cardiovascular dysfunction. The phosphoinositide-3 kinase (PI3K) signaling in the rostral ventrolateral medulla (RVLM), a key region for sympathetic outflow, is upregulated and contributes to increased blood pressure (BP) and sympathetic outflow in hypertension. This study was designed to determine the role of the PI3K signaling in neuroinflammation in the RVLM of hypertension.
METHODS: The normotensive WKY rats were performed by intracisternal infusion of lipopolysaccharide (LPS) or angiotensin II (Ang II) for inducing neuroinflammation. Elisa was used to determine the level of proinflammatory cytokines. Western blot was employed to detect the protein expression of PI3K signaling pathway. Gene silencing of PI3K p110δ subunit and overexpression of angiotensin-converting enzyme 2 (ACE2) were realized by injecting related lentivirus into the RVLM.
RESULTS: In the spontaneously hypertensive rats (SHR), the PI3K signaling in the RVLM was upregulated compared with WKY, gene silencing of PI3K in the RVLM significantly reduced BP and renal sympathetic nerve activity (RSNA), but also decreased the levels of proinflammatory cytokines. In the WKY rats, central infusion of LPS and Ang II significantly elevated BP and RSNA, but also increased the levels of proinflammatory cytokines and PI3K signaling activation in the RVLM. These changes in the Ang II-induced hypertension were effectively prevented by gene silencing of PI3K in the RVLM. Furthermore, overexpression of ACE2 in the RVLM significantly attenuated high BP and neuroinflammation, as well as decreased the activation of PI3K signaling in hypertensive rats.
CONCLUSION: This study suggests that the PI3K signaling in the RVLM is involved in neuroinflammation in hypertension and plays an important role in the renin-angiotensin system-mediated changes in neuroinflammation in the RVLM.