A THEMIS:SHP1 complex promotes T‐cell survival

THEMIS is critical for conventional T‐cell development, but its precise molecular function remains elusive. Here, we show that THEMIS constitutively associates with the phosphatases SHP1 and SHP2. This complex requires the adapter GRB2, which bridges SHP to THEMIS in a Tyr‐phosphorylation‐independent fashion. Rather, SHP1 and THEMIS engage with the N‐SH3 and C‐SH3 domains of GRB2, respectively, a configuration that allows GRB2‐SH2 to recruit the complex onto LAT. Consistent with THEMIS‐mediated recruitment of SHP to the TCR signalosome, THEMIS knock‐down increased TCR‐induced CD3‐ζ phosphorylation, Erk activation and CD69 expression, but not LCK phosphorylation. This generalized TCR signalling increase led to augmented apoptosis, a phenotype mirrored by SHP1 knock‐down. Remarkably, a KI mutation of LCK Ser59, previously suggested to be key in ERK‐mediated resistance towards SHP1 negative feedback, did not affect TCR signalling nor ligand discrimination in vivo. Thus, the THEMIS:SHP complex dampens early TCR signalling by a previously unknown molecular mechanism that favours T‐cell survival. We discuss possible implications of this mechanism in modulating TCR output signals towards conventional T‐cell development and differentiation.     

Childhood Chronic Physical Aggression Associates with Adult Cytokine Levels in Plasma

Background

An increasing number of animal and human studies are indicating that inflammation is associated with behavioral disorders including aggression. This study investigates the association between chronic physical aggression during childhood and plasma cytokine levels in early adulthood.

Methodology/Principal Findings

Two longitudinal studies were used to select males on a chronic physical aggression trajectory from childhood to adolescence (n = 7) and a control group from the same background (n = 25). Physical aggression was assessed yearly by teachers from childhood to adolescence and plasma levels of 10 inflammatory cytokines were assessed at age 26 and 28 years. Compared to the control group, males on a chronic physical aggression trajectory from childhood to adolescence had consistently lower plasma levels of five cytokines: lower pro-inflammatory interleukins IL-1α (T(28.7) = 3.48, P = 0.002) and IL-6 (T(26.9) = 3.76, P = 0.001), lower anti-inflammatory interleukin IL-4 (T(27.1) = 4.91, P = 0.00004) and IL-10 (T(29.8) = 2.84, P = 0.008) and lower chemokine IL-8 (T(26) = 3.69, P = 0.001). The plasma levels of four cytokines accurately predicted aggressive and control group membership for all subjects.

Conclusions/Significance

Physical aggression of boys during childhood is a strong predictor of reduced plasma levels of cytokines in early adulthood. The causal and physiological relations underlying this association should be further investigated since animal data suggest that some cytokines such as IL-6 and IL-1β play a causal role in aggression.