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An easy-to-synthesize Glu with the side chain modified by photosensitive p -methoxyphenacyl group was synthesized. It could be introduced into peptide by standard Fmoc-SPPS, be re-exposed by removing the photosensitive group under light irradiation. [Display omitted] The development of photocaged glutamic acid (Glu) contributes to the time-resolved control of peptide and protein activities. Here, we efficiently synthesized the Glu with the side chain modified by photosensitive p -methoxyphenacyl group. This photocaged Glu can be introduced into peptide through standard 9‑fluorenylmethoxycarbonyl (Fmoc) solid phase peptide synthesis (SPPS), and can be re-exposed the Glu side-chain carboxy group by removing the photosensitive group under light irradiation. We prepared caged Endothelin-1 (ET-1) analogues with p -methoxyphenacyl-modified Glu and successfully achieved decaging. [ABSTRACT FROM AUTHOR]

The photocaged glycine installed at position 64 and 92 of SUMO-2 prevented aspartimide formation and temporarily blocked probes activity, respectively, which enabled the expedient generation of on demand-activated SUMO-based probes that could be activated to capture SENPs upon photo-irradiation. [Display omitted] The transiently-activated SUMO probes are conducive to understand the dynamic control of SENPs activity. Here, we developed a photocaged glycine-assisted strategy for the construction of on demand-activated SUMO-ABPs. The light-sensitive groups installed at G92 and G64 backbone of SUMO-2 can temporarily block probes activity and hamper aspartimide formation, respectively, which enabled the efficient synthesis of inert SUMO-2 propargylamide (PA). The probe could be activated to capture SENPs upon photo-irradiation not only in vitro but also in intact cells, providing opportunities to further perform intracellular time-resolved proteome-wide profiling of SUMO-related enzymes. [ABSTRACT FROM AUTHOR]

Abstract Steroid-induced osteonecrosis of the femoral head (SONFH) is difficult to be diagnosed at the early stages when it can be administrated effectively. Yet, to date no study has been performed to identify diagnostic biomarkers and to develop diagnostic models for SONFH. In the current study, a total of 60 SONFH patients with Association Research Circulation Osseous (ARCO) stages I–IV, and 20 controls were enrolled and divided into the discovery and validation cohorts. The serum samples were collected and the gene expression profiles were detected by microarray analysis based on the discovery cohort. Then, eight genes (BIRC3, CBL, CCR5, LYN, PAK1, PTEN, RAF1 and TLR4) were identified as the candidate serum biomarkers of SONFH due to the significant differential expression patterns and the topological importance in the interaction network of SONFH-related differentially expressed genes. Functionally, these candidate serum biomarkers were significantly involved into several pathological processes during SONFH progression, such as the immune regulation and inflammation, bone metabolism and angiogenesis. After that, a prediction model for the diagnosis of SONFH was constructed using Partial least squares regression based on the serum levels of the candidate biomarkers. Notably, both the 10-fold cross-validation and the independent dataset test demonstrated the good performance of this model. In conclusion, our study discovered eight promising serum biomarkers and developed the multi-biomarker-based prediction model as a new, potential and non-invasive diagnostic tool for the detection of SONFH, as well as benefit the administration of SONFH in a daily clinical setting. Graphical abstract Unlabelled Image Highlights • Eight serum gene biomarkers were identified for the detection of SONFH. • The eight-biomarker serum gene signature-based diagnostic model for SONFH was developed. • The eight-biomarker serum gene signature-based diagnostic model displayed the good performance in predicting SONFH. [ABSTRACT FROM AUTHOR]

Highlights • This experiment is carried out based on patients with femoral head necrosis. • The accuracy of the experiment is at millimeter level. • This study mainly determined the relationship between density and elastic modulus for the entire femoral head. • The material properties of necrotic femoral heads and normal femoral heads are measured in this experiment using ultrasound scanning combined with CT scanning. Abstract Image-based finite element modelling has been commonly used to determine the biomechanical behaviours of human femora, particularly for the diagnosis of femoral head necrosis. One of the fundamental aspects of biomechanical modelling is the relationship between bone density, which is obtained from images, and elastic modulus. While there exist some empirical equations relating density with elastic modulus, the characterization of this relationship remains incomplete, especially for necrotic femoral heads. The objective of this study was to determine the relationship between density and elastic modulus by combining ultrasonic scanning and computed tomography (CT). Bone specimens were surgically removed from the femora of eight persons (seven females and one male in the age range of 55–68 years old) and underwent both ultrasonic and CT scanning. The images were processed with MATLAB scripts, and a bilinear interpolation algorithm was used to determine the relationship between the CT-measured densities and ultrasound-measured elastic moduli. The results showed different density–elastic modulus relations between the hardening strap of the necrotic region and non-hardening strap areas of the necrotic region. The uniqueness of this study is the characterization of mechanical properties (in the present study, the density–modulus relationship) from clinical images, which would be valuable in computational biomechanics used for the diagnosis and treatment evaluation of femoral head necrosis. [ABSTRACT FROM AUTHOR]