Inactivation of the tyrosine phosphatase SHP-2 drives vascular dysfunction in Sepsis

Abstract

Background Sepsis, the most severe form of infection, involves endothelial dysfunction which contributes to organ failure. To improve therapeutic prospects, elucidation of molecular mechanisms underlying endothelial vascular failure is of essence. Methods Polymicrobial contamination induced sepsis mouse model and primary endothelial cells incubated with sepsis serum were used to study SHP-2 in sepsis-induced endothelial inflammation. SHP-2 activity was assessed by dephosphorylation of pNPP, ROS production was measured by DCF oxidation and protein interactions were assessed by proximity ligation assay. Vascular inflammation was studied in the mouse cremaster model and in an in vitro flow assay. Findings We identified ROS-dependent inactivation of the tyrosine phosphatase SHP-2 to be decisive for endothelial activation in sepsis. Using in vivo and in vitro sepsis models, we observed a significant reduction of endothelial SHP-2 activity, accompanied by enhanced adhesion molecule expression. The impaired SHP-2 activity was restored by ROS inhibitors and an IL-1 receptor antagonist. SHP-2 activity inversely correlated with the adhesive phenotype of endothelial cells exposed to IL-1β as well as sepsis serum via p38 MAPK and NF-κB. In vivo , SHP-2 inhibition accelerated IL-1β-induced leukocyte adhesion, extravasation and vascular permeability. Mechanistically, SHP-2 directly interacts with the IL-1R1 adaptor protein MyD88 via its tyrosine 257, resulting in reduced binding of p85/PI3-K to MyD88. Interpretation Our data show that SHP-2 inactivation by ROS in sepsis releases a protective break, resulting in endothelial activation. Fund German Research Foundation, LMU Mentoring excellence and FöFoLe Programme, Verein zur Förderung von Wissenschaft und Forschung, German Ministry of Education and Research.

PECAM‐1 supports leukocyte diapedesis by tension‐dependent dephosphorylation of VE‐cadherin

“…Inhibition of SHP2 was suggested to enhance leukocyte-endothelial adhesion, but impair the diapedesis process (Yan et al, 2017). In line with the former result, SHP2 was found to become inactivated in sepsis which supported IL-1β induced NFkB-driven pro-inflammatory transcriptional activity and enhanced expression of ICAM-1 and VCAM-1 (Heun et al, 2019). Thus, SHP2 regulates multiple signaling mechanisms in endothelial cells which affect inflammatory processes in different ways.…”

TLR2-Deficiency Promotes Prenatal LPS Exposure-Induced Offspring Hyperlipidemia

“…Western blot analysis further confirmed a significant elevation of TLR4 and Myd88 protein levels in TLR2-deficient offspring-pLPS, while the expression of phospho-MyD88 Tyr257 was proportionally increased when normalized to total Myd88 protein levels in the TLR2-deficient offspring-pLPS adipose tissue (Figure 5D), suggesting that the activation of MyD88 is at the transcriptional level. Since the phosphorylation of Myd88 at Tyr257 is likely involved in the recruitment of PI-3 kinase p85 subunit to Myd88 for further inflammatory signal transduction, our results suggest that this process might not be affected by the genetic compensation of TLR4 alone, however, our results highlight the potential hypersensitivity in TLR2-deficient offspring-pLPS to additional inflammatory stimulation (Gelman et al, 2006; Heun et al, 2019).…”

Src Homology 2 Domain-Containing Protein Tyrosine Phosphatase Promotes Inflammation and Accelerates Osteoarthritis by Activating β-Catenin

“…The inflammation status in cartilage or periarticular tissues is mostly attributed to MAPK and NF-κB pathways whose hyperactivation directly initiate and target articular cartilage and subchondral bone, causing cartilage degeneration and subchondral bone formation. Previous studies have shown SHP2 mediated MAPK and NF-κB activation (Zou et al, 2007;Heun et al, 2019;Niogret et al, 2019;Liu et al, 2020). However, whether SHP2 regulated these signaling in OA pathogenesis was not fully elucidated.…”