Ankrd2 is a modulator of NF-κB-mediated inflammatory responses during muscle differentiation

Abstract

Adaptive responses of skeletal muscle regulate the nuclear shuttling of the sarcomeric protein Ankrd2 that can transduce different stimuli into specific adaptations by interacting with both structural and regulatory proteins. In a genome-wide expression study on Ankrd2-knockout or -overexpressing primary proliferating or differentiating myoblasts, we found an inverse correlation between Ankrd2 levels and the expression of proinflammatory genes and identified Ankrd2 as a potent repressor of inflammatory responses through direct interaction with the NF-κB repressor subunit p50. In particular, we identified Gsk3β as a novel direct target of the p50/Ankrd2 repressosome dimer and found that the recruitment of p50 by Ankrd2 is dependent on Akt2-mediated phosphorylation of Ankrd2 upon oxidative stress during myogenic differentiation. Surprisingly, the absence of Ankrd2 in slow muscle negatively affected the expression of cytokines and key calcineurin-dependent genes associated with the slow-twitch muscle program. Thus, our findings support a model in which alterations in Ankrd2 protein and phosphorylation levels modulate the balance between physiological and pathological inflammatory responses in muscle.

ANKRD1 modulates inflammatory responses in C2C12 myoblasts through feedback inhibition of NF-κB signaling activity

“…PCR amplification of DNA fragments immunoprecipitated with AnkrD1 antibody gave a single band of 500 bp as expected (27). Cells treated with TNFα resulted in an increase in density of the band suggesting enhanced binding of AnkrD1 to the region of chromatin in response to TNFα ( Figure 4A).…”

“…performed CHIP assays to determine whether exposure of C2C12 cells to TNFα induced recruitment of AnkrD1 to a NF-κB binding site previously reported in the AnkrD2 promoter (27). PCR amplification of DNA fragments immunoprecipitated with AnkrD1 antibody gave a single band of 500 bp as expected (27).…”

“…For example, AnkrD2 protein is able to modulate NF-κB transcriptional activity through direct interaction with the p50 subunit in human airway smooth muscle cells (27). Since the p50 subunit of NF-κB lacks a transactivation domain, its transcriptional activity is dependent on dimerization with other members of the NF-κB family, or on other co-regulators (28).…”

Global Deletion of Ankrd1 Results in a Wound-Healing Phenotype Associated with Dermal Fibroblast Dysfunction

“…Previous reports of deletion of one or all of the MARPs have detected minor effects. 6,7,19 The present findings in ischemic flaps and excisional wounds are highly consistent with the concept that ANKRD1 abundance becomes a rate-limiting factor when cells and tissues are challenged by injury and stress.…”

The Muscle Ankyrin Repeat Proteins CARP, Ankrd2, and DARP Are Not Essential for Normal Cardiac Development and Function at Basal Conditions and in Response to Pressure Overload

“…The generation of Ankrd2 KO mice has been described elsewhere [41]. For each of the three genes, the targeting vector was generated by replacement of the first 1–3 exons by lacZ and the neomycin resistance gene (neo), thereby disrupting gene expression (Fig.…”