CaMKKβ-Dependent Activation of AMP-Activated Protein Kinase Is Critical to Suppressive Effects of Hydrogen Sulfide on Neuroinflammation

Abstract

Aims: The manner in which hydrogen sulfide (H 2 S) suppresses neuroinflammation is poorly understood. We investigated whether H 2 S polarized microglia to an anti-inflammatory (M2) phenotype by activating AMPactivated protein kinase (AMPK). Results: Three structurally unrelated H 2 S donors (5-(4-hydroxyphenyl)-3H-1,2-dithiocyclopentene-3-thione [ADT-OH], (p-methoxyphenyl) morpholino-phosphinodithioic acid [GYY4137], and sodium hydrosulfide [NaHS]) enhanced AMPK activation in BV2 microglial cells in the presence and absence of lipopolysaccharide (LPS). The overexpression of the H 2 S synthase cystathionine bsynthase (CBS) in BV2 cells enhanced endogenous H 2 S production and AMPK activation regardless of LPS stimulation. On LPS stimulation, overexpression of both ADT-OH and CBS promoted M2 polarization of BV2 cells, as evidenced by suppressed M1 and elevated M2 signature gene expression. The promoting effects of ADT-OH on M2 polarization were attenuated by an AMPK inhibitor or AMPK knockdown. Liver kinase B1 (LKB1) and calmodulin-dependent protein kinase kinase b (CaMKKb) are upstream kinases that activate AMPK. ADT-OH activated AMPK in Hela cells lacking LKB1. In contrast, both the CaMKKb inhibitor and siRNA abolished ADT-OH activation of AMPK in LPS-stimulated BV2 cells. Moreover, the CaMKKb inhibitor and siRNA blunted ADT-OH suppression on M1 gene expression and enhancement of M2 gene expression in LPS-stimulated BV2 cells. Moreover, ADT-OH promoted M2 polarization of primary microglia in an AMPK activation-and CaMKKb-dependent manner. Finally, in an LPS-induced in vivo neuroinflammation model, both ADT-OH and NaHS enhanced AMPK activation in the brain area where microglia were overactivated on LPS stimulation. Furthermore, ADT-OH suppressed M1 and promoted M2 gene expression in this in vivo model. Innovation and Conclusion: CaMKKb-dependent AMPK activation is an unrecognized mechanism underlying H 2 S suppression on neuroinflammation.

Involvement of microRNA-135a-5p in the Protective Effects of Hydrogen Sulfide Against Parkinson's Disease

“…In addition, CaMKK-betadependent AMPK activation causes NaHS suppression of neuroinflammation [39]. Hence, it is likely that the model shown here may result from NaHS and ROCK's effects upon activated …”

Hydrogen sulfide protects against myocardial ischemia and reperfusion injury by activating AMP-activated protein kinase to restore autophagic flux

“…Recently we showed that H 2 S donors activated AMPK in several cell types [7,23]. In this study, ADT at the protective dose up- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 regulated AMPK activation following myocardial I/R.…”

“…We recently reported that ADT [5-(4-methoxyphenyl)-3H-1,2-dithiole-3-thione], a clinical drug approved in China and Europe, protected against cerebral ischemia as a slow-releasing organic H 2 S donor [6]. We also reported that ADT-based H 2 S donors activated AMPK more robustly than the well-established AMPK activator metformin [7]. However, it remains unknown if H 2 S donors act through AMPK activation to protect against myocardial I/R injury.…”

Activation of AMPK participates hydrogen sulfide-induced cyto-protective effect against dexamethasone in osteoblastic MC3T3-E1 cells

“…In cultured osteoblasts, activation of AMPK inhibits H 2 O 2 -induced cell apoptosis [16,17]. Recent studies have shown that H 2 S could activate AMPK [18,19], however its role in H 2 S-mediated cyto-protective activity is not fully understood.…”