OBJECTIVES-Human X-linked hypophosphatemia (XLH) and its murine homologue, Hyp are caused by inactivating mutations in PHEX gene. The protein encoded by PHEX gene is an endopeptidase whose physiological substrate(s) has not been identified. Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP), two members of the Small Integrin-Binding LIgand, N-linked Glycoprotein (SIBLING) family are proteolytically processed. It has been speculated that PHEX endopeptidase may be responsible for the proteolytic cleavage of DMP1 and DSPP. To test this hypothesis and to analyse the distribution of SIBLING proteins in the predentin/ dentin complex and mandible of Hyp mice, we compared the expression of four SIBLING proteins, DMP1, DSPP, bone sialoprotein (BSP) and osteopontin (OPN) between Hyp and wild-type mice.METHODS-These SIBLING proteins were analysed by protein chemistry and immunohistochemistry. RESULTS-(1)Dentin matrix protein 1 and DSPP fragments are present in the extracts of Hyp predentin/dentin and bone; (2) the level of DMP1 proteoglycan form, BSP and OPN is elevated in the Hyp bone.CONCLUSIONS-The PHEX protein is not the enzyme responsible for the proteolytic processing of DMP1 and DSPP. The altered distribution of SIBLING proteins may be involved in the pathogenesis of bone and dentin defects in Hyp and XLH.Keywords dentin matrix protein 1; dentin sialophosphoprotein; bone sialoprotein; osteopotin; X-linked hypophosphatemic rickets

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Understanding subclonal architecture and their biological functions poses one of the key challenges to deeply portray and investigative the cause of triple-negative breast cancer (TNBC). Here we combine single-cell and bulk sequencing data to analyze tumor heterogeneity through characterizing subclone compositions and proportions. Based on sing-cell RNA-seq data (GSE118389) we identified five distinct cell subpopulations and characterized their biological functions based on their gene markers. It is worth noting that C1 and C2 relate to immune functions, while C5 relates to programmed cell death. Then based on subclonal basis gene expression matrix, we applied CBS deconvolution algorithm on TCGA tissue RNA-seq data, and found that patients with low and high C1 proportions have different immune microenvironment;and high C5 proportions would led to poor survival outcome, p-value and HR [95%CI] for five years overall survival in TCGA dataset were 0.0326 and 1.664 [1.038-2.667], and in GSE96058 dataset were 0.0158 and 2.557 [1.160-5.636]. Collectively, our analysis reveals the both intra-tumor and inter-tumor heterogeneity and their association with subclonal microenvironment in TNBC (subclone compositions and proportions), and uncovers the organic combination of subclones dictating poor outcomes in this disease.