In systemic sclerosis (SSc), a common and etiologically mysterious form of scleroderma (defined as pathologic fibrosis of the skin), previously healthy adults acquire fibrosis of the skin and viscera in association with autoantibodies [1]. Familial recurrence is extremely rare and causal genes have not been identified. While the onset of fibrosis in SSc typically correlates with the production of autoantibodies, whether they contribute to disease pathogenesis or simply serve as a marker of disease remains controversial and the mechanism for their induction is largely unknown [2]. The study of SSc is hindered by a lack of animal models that recapitulate the etiology of this complex disease. To gain a foothold in the pathogenesis of pathologic skin fibrosis, we chose to study stiff skin syndrome (SSS), a rare but tractable Mendelian disorder that shows childhood onset of diffuse skin fibrosis with autosomal dominant inheritance and complete penetrance. We showed that SSS is caused by heterozygous missense mutations in the gene (FBN1) encoding fibrillin-1, the major constituent of extracellular microfibrils [3]. Notably, SSS mutations all localize to the only domain in fibrillin-1 that harbors an Arg-Gly-Asp (RGD) motif needed to mediate cell-matrix interactions by binding to cell-surface integrins [3]. Here we show that mouse lines that harbor analogous amino acid substitutions in fibrillin-1 recapitulate aggressive skin fibrosis that is prevented by integrin-modulating therapies and reversed by antagonism of the pro-fibrotic cytokine transforming growth factor β (TGFβ). Mutant mice show skin infiltration of pro-inflammatory immune cells including plasmacytoid dendritic, T helper, and plasma cells, and autoantibody production; these findings are normalized by integrin-modulating therapies or TGFβ antagonism. These data show that alterations in cell-matrix interactions are sufficient to initiate and sustain inflammatory and pro-fibrotic programs and highlight novel therapeutic strategies.

An oncogenic mutation (G49A:E17K) in the AKT1 gene has been described recently in human breast, colon, and ovarian cancers. The low frequency of this mutation and perhaps other selective pressures have prevented the isolation of human cancer cell lines that harbor this mutation thereby limiting functional analysis. Here, we create a physiologic in vitro model to study the effects of this mutation by using somatic cell gene targeting using the nontumorigenic human breast epithelial cell line, MCF10A. Surprisingly, knock in of E17K into the AKT1 gene had minimal phenotypic consequences and importantly, did not recapitulate the biochemical and growth characteristics seen with somatic cell knock in of PIK3CA hotspot mutations. These results suggest that mutations in critical genes within the PI3-kinase (PI3K) pathway are not functionally equivalent, and that other cooperative genetic events may be necessary to achieve oncogenic PI3K pathway activation in cancers that contain the AKT1 E17K mutation.

Deformational plagiocephaly (DP) in infants has been associated with developmental delay that can last until adolescence. Despite this association and a 5-fold increase in incidence of DP over the past 2 decades, there are currently no guidelines regarding screening for developmental delay or identification of which infants with DP are at the greatest risk of delay. A prospective, nonrandomized study was performed. Infants diagnosed with DP who had no prior intervention were eligible for enrollment. Cranial deformity was measured by cross-cranial measurements using calipers, and developmental delay was measured using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Correlation between cranial deformity and developmental delay was analyzed using a linear regression. Twenty-seven infants, ages 4.0 to 11.0 months (mean = 6.61 months) diagnosed with DP were studied. Developmental delay was observed on the composite language (n = 3 of 27, 11%), and composite motor (n = 5 of 23, 22%) scales, but not the cognitive scale. Severity of cranial deformity did not correlate with scores on any Bayley-III scales (cognitive R = 0.058, P = 0.238; composite language R = 0.03, P = 0.399; composite motor R = 0.0195, P = 0.536). This study demonstrates that severity of cranial deformity cannot be used to predict presence or degree of developmental delay. Craniofacial surgeons should be aware of this risk and consider developmental screening based on clinical suspicion.