Effects of NCSTN Mutation on Hair Follicle Components in Mice

Expression of nicastrin, NICD1, and Hes1 in NCSTN knockout mice: implications for hidradenitis suppurativa, Alzheimer's, and liver cancer

BACKGROUND

Nicastrin, a subunit of the γ-secretase complex, is encoded by the NCSTN gene and regulates notch signaling, it is involved in the pathogenesis of hidradenitis suppurativa (HS), Alzheimer disease (AD), and liver cancer. However, the animal models for studying HS are relatively scarce.

METHODS

CRISPR/Cas-mediated genetic engineering was used to generate targeted knockout offspring mice (C57BL/6J). Different doses (10 mg/kg, 20 mg/kg, and 30 mg/kg) and injection methods (subcutaneous/intraperitoneal/gavage injection) of tamoxifen were used to induce the construction of NCSTN knockout mice (mice model). The expressions of nicastrin, NICD1, hes1 in skin, brain, and liver tissue in mice model and wild-type (WT) mice were measured by qRT-PCR and IHC.

RESULTS

The construction of mice model was successfully induced by tamoxifen, knockout efficiency was 93%, there was no difference in knockout efficiency among three doses, injection methods, genders (P > 0.05). HS-like lesions appeared on the skin of NCSTN knockout mice after 1 month of treatment with tamoxifen, male mice had a higher number of skin lesions compared to female mice (male vs female = 76.5% vs 41.7%, P = 0.027). Compared with WT mice, the expressions of nicastrin (skin P = 0.0009, brain P = 0.0194, liver P = 0.0066), NICD1 (skin P = 0.0115, brain P = 0.0307, liver P = 0.008), hes1 (skin P = 0.0476, brain P = 0.0143, liver P = 0.0003) in mice model all decreased.

CONCLUSIONS

The NCSTN knockout mouse might be employed as HS animal model; Reducing nicastrin may affect the expression of notch1-hes1 pathway molecules in skin, brain, and liver tissues; low dose (10 mg/kg/d) tamoxifen could be used to induce the deletion of the target gene in mice.

Comprehensive analysis of skin growth-related hub genes and microenvironment characterization in a mouse expanded skin model

Background

Mechanical stretch-mediated tissue expansion is effective for obtaining extra skin and soft tissue required for the repair of defects or reconstruction of surface organs. Understanding the cellular and molecular mechanisms and identifying hub genes and key cell types associated with skin expansion could help predict the success of skin growth during expansion procedures.

Methods

We analyzed murine chip sequencing data and single-cell sequencing data available from the Gene Expression Omnibus database. Based on the differentially expressed and epithelial-mesenchymal transition-related genes, random forest and protein-protein interaction network analysis identified hub genes for predicting skin regeneration in tissue expansion. The fate of the cell subpopulations, expression of hub genes in different cell types, and their communication were also assessed.

Results

Five genes, integrin beta 5 (Itgb5), tropomyosin 1 (Tpm1), secreted frizzled-related protein-1 (Sfrp1), Notch1, and insulin-like growth factor binding protein 2 (Igfbp2), were identified as having the greatest impact on prediction accuracy. These hub genes were primarily enriched in the Notch and phosphoinositide 3-kinase-AKT pathways. Immune cell infiltration analysis further revealed that mast cell infiltration was significantly higher in the expanded skin group than that in the control group. According to single-cell data, the interactions between epithelial cells, stem cells, and other cell types were higher in the expanded skin group than those in the control group. Moreover, Tpm1, Sfrp1, and Notch1 were highly expressed in all epithelial and stem cell subgroups.

Conclusions

The hub genes, Notch1, Tpm1 and Sfrp1, and their associated signaling pathways such as Notch and Wnt signaling and functions in key cell subsets highlight prospective therapeutic strategies to enhance skin growth under mechanical expansion. Moreover, mast cell activation and infiltration may trigger immune responses in the expanded skin, which requires further investigation.

New precision medicine avenues to the prevention of Alzheimer's disease from insights into the structure and function of γ-secretases

Two phase-III clinical trials with anti-amyloid peptide antibodies have met their primary goal, i.e. slowing of Alzheimer's disease (AD) progression. However, antibody therapy may not be the optimal therapeutic modality for AD prevention, as we will discuss in the context of the earlier small molecules described as "γ-secretase modulators" (GSM). We review here the structure, function, and pathobiology of γ-secretases, with a focus on how mutations in presenilin genes result in early-onset AD. Significant progress has been made in generating compounds that act in a manner opposite to pathogenic presenilin mutations: they stabilize the proteinase-substrate complex, thereby increasing the processivity of substrate cleavage and altering the size spectrum of Aβ peptides produced. We propose the term "γ-secretase allosteric stabilizers" (GSAS) to distinguish these compounds from the rather heterogenous class of GSM. The GSAS represent, in theory, a precision medicine approach to the prevention of amyloid deposition, as they specifically target a discrete aspect in a complex cell biological signalling mechanism that initiates the pathological processes leading to Alzheimer's disease.