Chromatin profiling identifies chondrocyte-specific Sox9 enhancers important for skeletal development

Ichiyama-Kobayashi S., Hata K., Wakamori K., et al. Chromatin profiling identifies chondrocyte-specific Sox9 enhancers important for skeletal development. JCI Insight 9, e175486 (2024); https://doi.org/10.1172/jci.insight.175486.The transcription factor SRY-related HMG box 9 (Sox9) is essential for chondrogenesis. Mutations in and around SOX9 cause campomelic dysplasia (CD) characterized by skeletal malformations. Although the function of Sox9 in this context is well studied, the mechanisms that regulate Sox9 expression in chondrocytes remain to be elucidated. Here, we have used genome-wide profiling to identify 2 Sox9 enhancers located in a proximal breakpoint cluster responsible for CD. Enhancer activity of E308 (located 308 kb 5′ upstream) and E160 (located 160 kb 5′ upstream) correlated with Sox9 expression levels, and both enhancers showed a synergistic effect in vitro. While single deletions in mice had no apparent effect, simultaneous deletion of both E308 and E160 caused a dwarf phenotype, concomitant with a reduction of Sox9 expression in chondrocytes. Moreover, bone morphogenetic protein 2–dependent chondrocyte differentiation of limb bud mesenchymal cells was severely attenuated in E308/E160 deletion mice. Finally, we found that an open chromatin region upstream of the Sox9 gene was reorganized in the E308/E160 deletion mice to partially compensate for the loss of E308 and E160. In conclusion, our findings reveal a mechanism of Sox9 gene regulation in chondrocytes that might aid in our understanding of the pathophysiology of skeletal disorders

On the Correlation between Hydration of the Stratum Corneum and the Nutritional Status of Dialysis Patients

　Stratum corneum (SC) prevents evaporation of internal moisture and maintains dermal flexibility and fluidity. Malnutrition is known to decrease SC hydration, but involvement of nutritional status in SC hydration of dialysis patients is unclear. In this study, we examined the association between SC hydration and nutritional status on dialysis patients. We studied 16 control subjects and 81 dialysis patients to examine SC hydration of the neck, upper arm and lower leg. In the 81 patients, we measured serum albumin (Alb), transferrin, geriatric nutritional risk index (GNRI) and normalized protein catabolic rate (nPCR). We then classified the dialysis patients into a 21-patients group, with both Alb ≥ 3.6 g/dl and nPCR ≥ 0.9 g/kg/ day, and a 60-patients group with either Alb ＜3.6 g/dl or nPCR ＜0.9 g/kg/day. SC hydration in the lower leg and the Alb value in the 81 patients were significantly lower than those in the control subjects. SC hydration in the upper arm and lower leg and the values of transferrin and GNRI in the 60-patients group were significantly lower than those in the 21-patients group. This study demonstrates for the first time that nutritional status is correlated with maintenance of SC hydration on dialysis patients

Recognition and opinion of Nutritionists and Dietitians on the Gluten-Free Labeling System

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グルテンフリー表示制度に対する栄養士・管理栄養士の認識と見解について

近年、日本でもグルテンフリー（以下GF）食品が増加傾向にあるが、GF表示に関する法律は存在していない。我々は以前、栄養士・管理栄養士（計178名）を対象に、GF表示制度は必要かとの調査を行い、必要（55％）、不要（8.8％）、わからない（36％）との回答を得ている。今回、本論は、回答が分かれた理由は、各々が患者の健康を守ることを第一目的としながらも、それぞれの異なった考えに基づいて回答をしたことに拠るとの仮説を立てた。計量テキスト分析にて集団の回答理由を分析した結果、回答理由は①「安心できる食品選択」、②「患者が存在するから」、③「アレルギー患者の利益のため」、④「日本でGFは馴染みがない」、⑤「エビデンスもなく曖昧な現状のため」、⑥「自分の知識不足」に分けられた。そして、これらは、そのまま①②③が必要、④⑤が不必要、⑥がわからない、と答えた群の意見であることが判明した。よって、我々の仮説の妥当性を検証し得たと主張する