A pig model carrying heterozygous point mutation of NCSTN simulates familial acne inversa and reveals dysregulated cholesterol biosynthesis via the Notch-pAMPK-HMGCR pathway

Upregulation of TLR2 in keratinocytes activates the MAPK pathway and plays a role in the pathogenesis of hidradenitis suppurativa

BACKGROUND

Mutations in gamma-secretase complex (GSC) genes are associated with hidradenitis suppurativa (HS), and toll-like receptor (TLR) 2 is elevated in HS lesions. However, it remains unclear whether TLR2 is upregulated in the skin lesions of patients with HS with GSC gene variants, and the role of its upregulation in the pathogenesis of this disease are unknown.

OBJECTIVE

To investigate the role of TLR2 upregulation in NCSTN and PSENEN knockdown keratinocytes.

METHODS

Human immortalized keratinocyte line (HaCaTs) was treated with potent short-hairpin RNA targeting NCSTN or PSENEN. RNA sequencing was used to assess the effects of PAM2CSK4 treatment on gene expression in HaCaT cells. Altered signaling pathways were confirmed in both HaCaT cells, as well as in skin lesions from patients with HS and in Ncstn keratinocyte-specific knockout (NcstnΔKC) mice.

RESULTS

TLR2 agonist stimulation exacerbated the increased phosphorylation levels of extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase (MAPK) in NCSTN- and PSENEN- knockdown keratinocytes. Similar findings were observed in skin lesions from patients with HS and NcstnΔKC mice.

CONCLUSION

Novel variations were identified within the GSC gene in Chinese patients with HS. Moreover, our study indicates that TLR2/MAPK signaling pathways play a key role in the pathogenesis of HS associated with GSC gene mutations and represent a crucial therapeutic target.

Discovery and Potential Functional Characterization of Long Noncoding RNAs Associated with Familial Acne Inversa with NCSTN Mutation

BACKGROUND

Long noncoding RNAs (lncRNAs) are associated with many dermatologic diseases. However, little is known about the regulatory function of lncRNAs in familial acne inversa (AI) patients with nicastrin (NCSTN) mutation.

OBJECTIVES

The aim of this study was to explore the regulatory function of lncRNAs in familial AI patients with NCSTN mutation.

METHODS

The expression profiles of lncRNAs and mRNAs in skin tissues from familial AI patients with NCSTN mutation and healthy individuals were analysed in this study via RNA sequencing (RNA-seq).

RESULTS

In total, 359 lncRNAs and 1,863 mRNAs were differentially expressed between the two groups. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed that the dysregulated mRNAs targeted by lncRNAs were mainly associated with the immune regulation, Staphylococcus aureus infection and B cell receptor signalling pathways. The lncRNA-miRNA-mRNA coexpression network contained 265 network pairs comprising 55 dysregulated lncRNAs, 11 miRNAs, and 74 mRNAs. Conservation analysis of the differentially expressed lncRNAs between familial AI patients with NCSTN mutation and Ncstn keratinocyte-specific knockout (NcstnΔKC) mice identified 6 lncRNAs with sequence conservation; these lncRNAs may participate in apoptosis, proliferation, and skin barrier function.

CONCLUSIONS

These findings provide a direction for exploring the regulatory mechanisms underlying the progression of familial AI patients with NCSTN mutation.