PMID- 35804301 OWN - NLM STAT- MEDLINE DCOM- 20220712 LR - 20221220 IS - 1471-2180 (Electronic) IS - 1471-2180 (Linking) VI - 22 IP - 1 DP - 2022 Jul 8 TI - Cyclic-di-GMP stimulates keratinocyte innate immune responses and attenuates methicillin-resistant Staphylococcus aureus colonization in a murine skin wound infection model. PG - 176 LID - 10.1186/s12866-022-02583-1 [doi] LID - 176 AB - BACKGROUND: Staphylococcus aureus is a leading cause for morbidity and mortality associated with skin and burn wound infections. Therapeutic options for methicillin-resistant S. aureus (MRSA) have dwindled and therefore alternative treatments are urgently needed. In this study, the immuno-stimulating and anti-MRSA effects of cyclic di-guanosine monophosphate (c-di-GMP), a uniquely bacterial second messenger and immuno-modulator, were investigated in HaCaT human epidermal keratinocytes and a murine skin wound infection model. RESULTS: Stimulation of HaCaT cells with 125 muM c-di-GMP for 12 h prior to MRSA challenge resulted in a 20-fold reduction in bacterial colonization compared with untreated control cells, which was not the result of a direct c-di-GMP toxic effect, since bacterial viability was not affected by this dose in the absence of HaCaT cells. C-di-GMP-stimulated or MRSA-challenged HaCaT cells displayed enhanced secretion of the antimicrobial peptides human beta-defensin 1 (hBD-1), hBD-2, hBD-3 and LL-37, but for hBD1 and LL-37 the responses were additive in a c-di-GMP-dose-dependent manner. Secretion of the chemokines CXCL1 and CXCL8 was also elevated after stimulation of HaCaT cells with lower c-di-GMP doses and peaked at a dose of 5 muM. Finally, pre-treatment of mice with a 200 nmol dose of c-di-GMP 24 h before a challenge with MRSA in skin wound infection model resulted in a major reduction (up to 1,100-fold by day 2) in bacterial CFU counts recovered from challenged skin tissue sections compared PBS-treated control animals. Tissue sections displayed inflammatory cell infiltration and enhanced neutrophil influx in the c-di-GMP pre-treated animals, which might account for the reduced ability of MRSA to colonize c-di-GMP pre-treated mice. CONCLUSIONS: These results demonstrate that c-di-GMP is a potent immuno-modulator that can stimulate anti-MRSA immune responses in vivo and might therefore be a suitable alternative prophylactic or therapeutic agent for MRSA skin or burn wound infections. CI - (c) 2022. The Author(s). FAU - Gao, Shuai AU - Gao S AD - Department of Medical Microbiology and Parasitology, and Department of Infection of the Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, 866Yuhangtang Road, West Lake District, Hangzhou, 310058, China. FAU - Khan, Abidullah AU - Khan A AD - Department of Burns, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China. FAU - Chen, Xuhong AU - Chen X AD - Department of Medical Microbiology and Parasitology, and Department of Infection of the Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, 866Yuhangtang Road, West Lake District, Hangzhou, 310058, China. FAU - Xiao, Guohui AU - Xiao G AD - Department of Medical Microbiology and Parasitology, and Department of Infection of the Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, 866Yuhangtang Road, West Lake District, Hangzhou, 310058, China. FAU - van der Veen, Stijn AU - van der Veen S AD - Department of Microbiology, and Department of Dermatology of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, China. FAU - Chen, Yin AU - Chen Y AD - Key Laboratory of Emergency Detection for Public Health of Zhejiang Province, Zhejiang Provincial Center for Disease Control and Prevention, 3399 Binsheng Road, Binjiang District, Hangzhou, 310051, China. yinch@cdc.zj.cn. FAU - Lin, Xu'ai AU - Lin X AD - Department of Medical Microbiology and Parasitology, and Department of Infection of the Children's Hospital, National Clinical Research Center for Child Health, School of Medicine, Zhejiang University, 866Yuhangtang Road, West Lake District, Hangzhou, 310058, China. lxai122@zju.edu.cn. LA - eng PT - Journal Article DEP - 20220708 PL - England TA - BMC Microbiol JT - BMC microbiology JID - 100966981 RN - 0 (Adjuvants, Immunologic) RN - 61093-23-0 (bis(3',5')-cyclic diguanylic acid) RN - H2D2X058MU (Cyclic GMP) SB - IM MH - *Adjuvants, Immunologic/pharmacology/therapeutic use MH - Animals MH - Burns/complications MH - Cyclic GMP/*analogs & derivatives/pharmacology/therapeutic use MH - Disease Models, Animal MH - Humans MH - *Immunity, Innate/drug effects MH - Keratinocytes/drug effects MH - *Methicillin-Resistant Staphylococcus aureus/drug effects MH - Mice MH - *Staphylococcal Skin Infections/drug therapy PMC - PMC9264594 OTO - NOTNLM OT - Immunomodulatory OT - MRSA OT - Skin infection OT - c-di-GMP COIS- We declare that we have no conflict of interests. EDAT- 2022/07/09 06:00 MHDA- 2022/07/14 06:00 PMCR- 2022/07/08 CRDT- 2022/07/08 23:41 PHST- 2021/11/03 00:00 [received] PHST- 2022/06/22 00:00 [accepted] PHST- 2022/07/08 23:41 [entrez] PHST- 2022/07/09 06:00 [pubmed] PHST- 2022/07/14 06:00 [medline] PHST- 2022/07/08 00:00 [pmc-release] AID - 10.1186/s12866-022-02583-1 [pii] AID - 2583 [pii] AID - 10.1186/s12866-022-02583-1 [doi] PST - epublish SO - BMC Microbiol. 2022 Jul 8;22(1):176. doi: 10.1186/s12866-022-02583-1.