Hedgehog interacting protein as a circulating biomarker in women with obesity: a cross-sectional study and intervention studies

BACKGROUND

Although a study found a significant increase in serum hedgehog interacting protein (HHIP) concentrations in impaired fasting blood glucose, impaired glucose tolerance and newly diagnosed T2DM patients, the variation in circulating HHIP levels in obese individuals remains unknown.

PATIENTS AND METHODS

Gene Set Enrichment Analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were used for differentially expressed genes and signal pathways. The study is comprised of a total of 452 young women, including 248 obese individuals and 204 controls. Circulating HHIP and Adipoq levels were determined with ELISA kits. Euglycemic-hyperinsulinemic clamps (EHC) and oral glucose tolerance test (OGTT) were conducted in every subject. 32 women were given metformin and 49 were given liraglutide treatment for 6 weeks. The study was registered with www.chictr.org.cn (ChiCTR2000032878 and ChiCTR1800019776).

RESULTS

Obesity was significantly associated with the cAMP signal pathway, and HHIP was a secreted protein related to cAMP signalling, as determined by KEGG analysis. In this population-based cohort study, we found that the level of circulating HHIP was significantly elevated in obese women, and positively correlated with body mass index and blood glucose, blood lipid, insulin, homeostasis model assessment of insulin resistance, dehydroepiandrostenedione sulphate, and luteinizing hormone, while negatively correlated with M-value and Adipoq. Insulin resistance (IR) and ove™rweight/obesity were associated with the higher HHIP concentration. OGTT and EHC tests revealed that the levels of circulating HHIP were regulated by blood glucose but to a less extent by insulin. After therapy with metformin and liraglutide, circulating HHIP levels were decreased, whereas Adipoq levels increased significantly.

CONCLUSIONS

Our findings support HHIP as a potential biomarker for predicting obesity and IR. In addition, drugs targeting HHIP may be a new strategy to treat obesity.

Bioinformatics analysis of hedgehog interacting protein in colorectal cancer: a study based on GEO data and TCGA data

Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide. Hedgehog Interacting Protein (HHIP) is evolutionarily conserved protein, which are important morphogens for a wide range of developmental processes,However, the specific role and mechanism of HHIP in CRC remains not fully understood. In this study, we first performed pan-cancer analysis for HHIP's expression via The Cancer Genome Atlas (TCGA) and The Genotype-Tissue Expression (GTEx) data and found that HHIP might be a potential anti-oncogene for CRC. Subsequently, non-coding RNAs (ncRNAs) contributing to down-regulated HHIP expression were identified through a combination of a series of in silico analyses, including expression and correlation analysis. Finally, the LINC02381/miR-577 complex was identified as the top potential upstream regulator of HHIP in CRC. In addition, HHIP expression level was significantly correlated with tumor immune cell infiltration, biomarkers of immune cells, and immune checkpoint expression. Overall, our findings clarified ncRNAs-mediated down-regulation of HHIP which was associated with poor prognosis and tumor immune infiltration in CRC.

Hedgehog interacting protein activates sodium-glucose cotransporter 2 expression and promotes renal tubular epithelial cell senescence in a mouse model of type 1 diabetes

AIMS/HYPOTHESIS

Senescent renal tubular cells may be linked to diabetic kidney disease (DKD)-related tubulopathy. We studied mice with or without diabetes in which hedgehog interacting protein (HHIP) was present or specifically knocked out in renal tubules (Hhip^RT-KO), hypothesising that local deficiency of HHIP in the renal tubules would attenuate tubular cell senescence, thereby preventing DKD tubulopathy.

METHODS

Low-dose streptozotocin was employed to induce diabetes in both Hhip^RT-KO and control (Hhip^fl/fl) mice. Transgenic mice overexpressing Hhip in renal proximal tubular cells (RPTC) (Hhip^RPTC-Tg) were used for validation, and primary RPTCs and human RPTCs (HK2) were used for in vitro studies. Kidney morphology/function, tubular senescence and the relevant molecular measurements were assessed.

RESULTS

Compared with Hhip^fl/fl mice with diabetes, Hhip^RT-KO mice with diabetes displayed lower blood glucose levels, normalised GFR, ameliorated urinary albumin/creatinine ratio and less severe DKD, including tubulopathy. Sodium-glucose cotransporter 2 (SGLT2) expression was attenuated in RPTCs of Hhip^RT-KO mice with diabetes compared with Hhip^fl/fl mice with diabetes. In parallel, an increased tubular senescence-associated secretory phenotype involving release of inflammatory cytokines (IL-1β, IL-6 and monocyte chemoattractant protein-1) and activation of senescence markers (p16, p21, p53) in Hhip^fl/fl mice with diabetes was attenuated in Hhip^RT-KO mice with diabetes. In contrast, Hhip^RPTC-Tg mice had increased tubular senescence, which was inhibited by canagliflozin in primary RPTCs. In HK2 cells, HHIP overexpression or recombinant HHIP increased SGLT2 protein expression and promoted cellular senescence by targeting both ataxia-telangiectasia mutated and ataxia-telangiectasia and Rad3-related-mediated cell arrest.

CONCLUSIONS/INTERPRETATION

Tubular HHIP deficiency prevented DKD-related tubulopathy, possibly via the inhibition of SGLT2 expression and cellular senescence.

Exosomal microRNAs in the DLK1-DIO3 imprinted region derived from cancer-associated fibroblasts promote progression of hepatocellular carcinoma by targeting hedgehog interacting protein

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most commonly diagnosed cancer and third leading cause of cancer-related death worldwide in 2020. Exosomes derived from cancer-associated fibroblasts (CAFs-exo) can promote tumor progression in various human cancers. However, the underlying regulatory mechanism controlling how CAFs-exo can promote HCC progression remains poorly understood.

METHODS

CAFs and para-cancer fibroblasts (PAFs) were isolated from HCC tissues and corresponding para-cancer tissues, then were cultured in vitro. CAFs and PAFs were characterized by immunofluorescence and western blot (WB) assays. Exosomes were isolated by ultracentrifugation, and characterized by transmission electron microscopy, nanoflow cytometry, and WB assay. The internalization of exosomes by HCC cells was observed under a fluorescence microscope. Cell Counting Kit-8 (CCK-8) assay was used to evaluate cell proliferation. Wound healing and transwell assays were used for migration and invasion experiments. RT-PCR assay was used to examine differentially expressed microRNAs (miRNAs) in exosomes and HCC cells. The TargetScan database was used to predict miRNA target genes. Hedgehog interacting protein (HHIP) expression analysis, prognostic analysis, and enrichment analysis of HHIP-related co-expressed genes were performed using the TIMER, UALCAN, Kaplan-Meier plotter, and LinkedOmics databases.

RESULTS

CAFs-exo were internalized by HCC cells. CAFs-exo contributed to the aggressive phenotype of HCC cells, while inhibiting exosome secretion reversed these effects. Mechanistically, miRNAs in the DLK1-DIO3 imprinted region (miR-329-3p, miR-380-3p, miR-410-5p, miR-431-5p) were increased in HCC cells co-cultured with CAFs-exo compared with PAFs-exo. Expression of HHIP, a possible miR-431-5p target gene, was significantly downregulated in HCC cells. Low HHIP expression level in tumor tissues could predict poor prognosis in HCC patients. HHIP-related co-expressed genes were mainly associated with cell adhesion molecules.

CONCLUSIONS

CAFs-exo can promote HCC progression by delivering miRNAs in the DLK1-DIO3 imprinted region to HCC cells, subsequently inhibiting HHIP expression. HHIP is a potential prognostic biomarker in HCC.

Hedgehog (HH) pathway endogenous antagonist HHIP: unique lingual expression in filiform papillae during homeostasis and ectopic in fungiform papillae during HH signaling inhibition

BACKGROUND

Hedgehog (HH) signaling is essential for homeostasis in gustatory fungiform papillae (FP) and taste buds. However, activities of HH antagonists in these tissues remain unexplored. We investigated a potential role for HH-interacting protein (HHIP), an endogenous pathway antagonist, in regulating HH signaling during taste organ homeostasis. We found a restricted pattern of Hhip-expressing cells in the anterior epithelium of each nongustatory filiform papilla (FILIF) only. To test for roles in antagonism of HH signaling, we investigated HHIP after pathway inhibition with SMO inhibition via sonidegib and Smo deletion, Gli2 deletion/suppression, or with chorda tympani/lingual nerve cut.

RESULTS

In all approaches, the HHIP expression pattern was retained in FILIF suggesting HH-independent regulation of HHIP. Remarkably, after pathway inhibition, HHIP expression was detected also in the conical, FILIF-like atypical FP. We found a close association of de novo expression of HHIP in atypical FP with loss of Gli1+, HH-responding cells. Further, we report that PTCH1 is another potential HH antagonist in FILIF that co-localizes with HHIP.

CONCLUSIONS

After HH pathway inhibition the ectopic expression of HHIP correlates with a FILIF-like morphology in atypical FP and we propose that localized expression of the HH antagonist HHIP regulates pathway inhibition to maintain FILIF during tongue homeostasis. This article is protected by copyright. All rights reserved.

Expression of Sonic Hedgehog and pathway components in the embryonic mouse head: anatomical relationships between regulators of positive and negative feedback

Objective

The Hedgehog pathway is a fundamental signaling pathway in organogenesis. The expression patterns of the ligand Sonic Hedgehog (Shh) and key pathway components have been studied in many tissues but direct spatial comparisons across tissues with different cell compositions and structural organization are not common and could reveal tissue-specific differences in pathway dynamics.

Results

We directly compared the expression characteristics of Shh, and four genes with functional roles in signaling and whose expression levels serve as readouts of pathway activity in multiple tissues of the embryonic mouse head at embryonic day 15.5 by serial in situ hybridization. The four readout genes were the positive feedback regulator Gli1, and three negative feedback regulators, Patched1, Patched2, and Hedgehog Interacting Protein. While the relative abundance of Gli1 was similar across tissues, the relative expression levels and spatial distribution of Shh and the negative feedback regulators differed, suggesting that feedback regulation of hedgehog signaling is context dependent. This comparative analysis offers insight into how consistent pathway activity could be achieved in tissues with different morphologies and characteristics of ligand expression.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05714-5.