Rho-kinase inhibitor hydroxyfasudil protects against HIV-1 Tat-induced dysfunction of tight junction and neprilysin/Aβ transfer receptor expression in mouse brain microvessels

Abstract

HIV-1 transactivator protein (Tat) induces tight junction (TJ) dysfunction and amyloid-beta (Aβ) clearance dysfunction, contributing to the development and progression of HIV-1-associated neurocognitive disorder (HAND). The Rho/ROCK signaling pathway has protective effects on neurodegenerative disease. However, the underlying mechanisms of whether Rho/ROCK protects against HIV-1 Tat-caused dysfunction of TJ and neprilysin (NEP)/Aβ transfer receptor expression have not been elucidated. C57BL/6 mice were administered sterile saline (i.p., 100 μL) or Rho-kinase inhibitor hydroxyfasudil (HF) (i.p., 10 mg/kg) or HIV-1 Tat (i.v., 100 μg/kg) or HF 30 min before being exposed to HIV-1 Tat once a day for seven consecutive days. Evans Blue (EB) leakage was detected via spectrophotometer and brain slides in mouse brains. The protein and mRNA levels of zonula occludens-1 (ZO-1), occludin, NEP, receptor for advanced glycation end products (RAGE), and low-density lipoprotein receptor-related protein 1 (LRP1) in mouse brain microvessels were, respectively, analyzed by Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) analyses. Exposure of the mice to HIV-1 Tat increased the amount of EB leakage, EB fluorescence intensity, blood–brain barrier (BBB) permeability, as well as the RAGE protein and mRNA levels, and decreased the protein and mRNA levels of ZO-1, occludin, NEP, and LRP1 in mouse brain microvessels. However, these effects were weakened by Rho-kinase inhibitor HF. Taken together, these results provide information that the Rho/ROCK signaling pathway is involved in HIV-1 Tat-induced dysfunction of TJ and NEP/Aβ transfer receptor expression in the C57BL/6 mouse brain. These findings shed some light on potentiality of inhibiting Rho/Rock signaling pathway in handling HAND.

Intraneuronal β-Amyloid Accumulation: Aging HIV-1 Human and HIV-1 Transgenic Rat Brain

“…First, the HIV-1 transactivator of transcription (tat) and envelope glycoprotein gp120 (gp120) may promote the synthesis, secretion, and accumulation of β-amyloid [23,39]. Second, tat and/or tat-derived peptides may inhibit neprilysin [39,41,42], a key enzyme for β-amyloid degradation [43]. In addition, it is well-recognized that the blood-brain barrier (BBB) is compromised by HIV-1 viral proteins (for review, [44]); dysfunction which may influence β-amyloid homeostasis.…”

HIV-1 Tat Upregulates the Receptor for Advanced Glycation End Products and Superoxide Dismutase-2 in the Heart of Transgenic Mice

“…In addition to mitochondrial damage, RAGE contributes to aortic structural changes characterized by increased collagen deposition in rodents [ 108 , 112 ]. Recent studies have indicated that HIV-1 Tat-induced RAGE expression within the blood–brain barrier accelerates amyloid beta deposition [ 36 , 37 , 38 ]. The influence of RAGE within the heart could also be an underlying mechanism for Tat-induced CVDs.…”

“…Furthermore, Tat induces bradycardia by activating parasympathetic neurons within the nucleus ambiguous [ 35 ] and mediates vascular aging in rodents [ 30 ]. Although the Tat-mediated mechanisms that may contribute to CVDs are not well understood, Tat has been demonstrated to upregulate the receptor for advanced glycation end products (RAGE) within the blood-brain barrier [ 36 , 37 , 38 ], a receptor target known to be involved in CVD [ 39 , 40 ].…”

Poly(I:C) promotes neurotoxic amyloid β accumulation through reduced degradation by decreasing neprilysin protein levels in astrocytes

“…In addition, TLR3 is activated by the dsRNA analog, polyinosinic:polycytidylic acid (poly[I:C]) (Hanke & Kielian, 2011). New evidence indicates the role of viruses, including human herpes virus (HSV) 1, 6A, and 7, and hepatitis B viruses, in the pathology of Alzheimer's disease (AD) (Chen et al, 2021; Civitelli et al, 2015; Mastroeni et al, 2018; Readhead et al, 2018). HSV‐1‐infected neuron inactivates neprilysin (NEP) and glycogen synthase kinase 3β, whose products are involved in Aβ clearance and tau phosphorylation, respectively (Civitelli et al, 2015).…”

“…HSV‐1‐infected neuron inactivates neprilysin (NEP) and glycogen synthase kinase 3β, whose products are involved in Aβ clearance and tau phosphorylation, respectively (Civitelli et al, 2015). Human immunodeficiency virus (HIV) 1 transactivator protein induces Aβ clearance dysfunction through decreased NEP protein levels (Chen et al, 2021). The extracellular Aβ levels increase through lower NEP expression coupled with a significant decrease in its activity in primary cultures of HIV‐1 infected astrocytes (Martínez‐Bonet et al, 2019).…”