Collagen triple helix repeat containing-1 promotes functional recovery of sweat glands by inducing adjacent microvascular network reconstruction in vivo

Background:Sweat glands(SGs)have low regenerative potential after severe burns or trauma and their regeneration or functional recovery still faces many obstacles.In practice,restoring SG function requires not only the structural integrity of the gland itself,but also its neighboring tissues,especially blood vessels.Collagen triple helix repeat containing-1(CTHRC1)was first identified in vascular repair,and increasing reports showed a close correlation between cutaneous appendage specification,patterning and regeneration.The purpose of the present study was to clarify the role of CTHRC1 in SGs and their adjacent microvessels and find therapeutic strategies to restore SG function.Methods:The SGs and their adjacent microvascular network of Cthrc^(1−/−)mice were first inves-tigated using sweat test,laser Doppler imaging,tissue clearing technique and transcriptome analysis.The effects of CTHRC1 on dermal microvascular endothelial cells(DMECs)were further explored with cell proliferation,DiI-labeled acetylated low-density lipoprotein uptake,tube for-mation and intercellular junction establishment assays.The effects of CTHRC1 on SG function restoration were finally confirmed by replenishing the protein into the paws of Cthrc(1−/−)mice.Results:CTHRC1 is a key regulator of SG function in mice.At the tissue level,Cthrc1 deletion resulted in the disorder and reduction of the microvascular network around SGs.At the molecular level,the knockout of Cthrc1 reduced the expression of vascular development genes and functional proteins in the dermal tissues.Furthermore,CTHRC1 administration considerably enhanced SG function by inducing adjacent vascular network reconstruction.Conclusions:CTHRC1 promotes the development,morphogenesis and function execution of SGs and their neighboring vasculature.Our study provides a novel target for the restoration or regeneration of SG function in vivo.

Hepatitis B virus hijacks CTHRC1 to evade host immunity and maintain replication

HepatitisBvirus(HBV)infection causes acuteand chronic liver diseases,but is not directly cytopathic.Liver injury results fromrepeated attempts of the cellular immune response system to control the viral infection.Here,we investigate the roles of cellular factors and signaling pathways involved in the regulation of HBV replication to reveal the mechanism underlying HBV infection and pathogenesis.Weshowthat collagen triple helix repeat containing 1(CTHRC1)expression is elevated in HBV-infected patients andin HBV-transfected cells through epigenetic modification and transcriptional regulation.CTHRC1 facilitates HBV replication in cultured cells and BALB/c mice by activating the PKCa/ERK/JNK/c-Jun cascade to repress the IFN/JAK/STAT pathway.HBV-activated CTHRC1 downregulates the activityof typeI interferon(IFN),theproductionof IFN-stimulatedgenes(ISGs),andthephosphorylationofsignal transducerandactivator of transcription 1/2(STAT1/2),whereas it upregulates the phosphorylation and ubiquitination of type I IFN receptors(IFNARa/b).Thus,our results showthat HBV uses a novelmechanismto hijack cellular factors and signal cascades in order to evade host antiviral immunity and maintain persistent infection.We also demonstrate that CTHRC1 has a novel role in viral infection.