Ccl2/Ccr2 signalling recruits a distinct fetal microchimeric population that rescues delayed maternal wound healing

Pr Sélim ARACTINGI, Mathieu Castela, Dany Nassar, Maria Sbeih, Marie Jachiet, Zhe Wang

Nature Communication


Foetal microchimeric cells (FMCs) traffic into maternal circulation during pregnancy and persist for decades after delivery. Upon maternal injury, FMCs migrate to affected sites where they participate in tissue healing. However, the specific signals regulating the trafficking of FMCs to injury sites had to be identified. Here we report that, in mice, a subset of FMCs implicated in tissue repair displays CD11bþ CD34þ CD31þ phenotype and highly express C-C chemokine receptor 2 (Ccr2). The Ccr2 ligand chemokine ligand 2 (Ccl2) enhances the recruitment of FMCs to maternal wounds where these cells transdifferentiate into endothelial cells and stimulate angiogenesis through Cxcl1 secretion. Ccl2 administration improves delayed maternal wound healing in pregnant and postpartum mice but never in virgin ones. This role of Ccl2/Ccr2 signalling opens new strategies for tissue repair through natural stem cell therapy, a concept that can be later applied to other types of maternal diseases.

Re-Epithelialization of Pathological Cutaneous Wounds Is Improved by Local Mineralocorticoid Receptor Antagonism

Pr Sélim ARACTINGI, Nguyen VT, Farman N, Maubec E, Nassar D, Desposito D, Waeckel L, Jaisser F

J Invest Dermatol


Impaired cutaneous wound healing is a social burden. It occurs as a consequence of glucocorticoid treatment in several pathologies. Glucocorticoids (GC) bind not only to the glucocorticoid receptor but also to the mineralocorticoid receptor (MR), both expressed by keratinocytes. In addition to its beneficial effects through the glucocorticoid receptor, GC exposure may lead to inappropriate MR occupancy. We hypothesized that dermatological use of MR antagonists (MRA) might be beneficial by overcoming the negative impact of GC treatment on pathological wounds. The potent GC clobetasol, applied as an ointment to mouse skin, or added to cultured human skin explants, induced delayed wound closure and outgrowth of epidermis with reduced proliferation of keratinocytes. Delayed wound re-epithelialization was rescued by local MRA application. Normal skin was unaffected by MRA. The benefit of MR blockade is explained by the increased expression of MR in clobetasol-treated mouse skin. Blockade of the epithelial sodium channel by phenamil also rescued cultured human skin explants from GC-impaired growth of the epidermis. MRA application over post-biopsy wounds of clobetasol-treated skin zones of healthy volunteers (from the Interest of Topical Spironolactone's Administration to Prevent Corticoid-induced Epidermal Atrophy clinical trial) also accelerated wound closure. In conclusion, we propose repositioning MRA for cutaneous application to improve delayed wound closure occurring in pathology.

Delayed Healing of Sickle Cell Ulcers Is due to Impaired Angiogenesis and CXCL12 Secretion in Skin Wounds

Pr Sélim ARACTINGI, Nguyen VT, Nassar D, Batteux F, Raymond K, Tharaux PL

J Invest Dermatol


Leg ulcers are a major complication of sickle cell disease that occur in 2.5-40% of patients. Leg ulcers are responsible for frequent complications because they are often long-lasting and are highly resistant to therapy. Although their occurrence is associated with hyperhemolysis, the mechanisms underlying sickle cell ulcers remain poorly understood. In this study, we show that skin wound healing is severely altered in old SAD sickle cell mice but is normal in young animals, consistent with reports in humans. Alterations of wound healing were associated with impaired blood and lymphatic angiogenesis in the wound beds and poor endothelial progenitor cell mobilization from the bone marrow. CXCL12 secretion by keratinocytes and inflammatory cells was low in the wounds of SAD mice. Local therapy with endothelial progenitor cells or recombinant CXCL12 injections restored wound angiogenesis and rescued the healing defect together with mobilization of circulating endothelial progenitor cells. To our knowledge, this is a previously unreported study of the cellular and molecular mechanisms of sickle cell ulcers in a murine model that provides promising therapeutic perspectives for clinical trials.

Prognostic Value of 25-hydroxyvitamin D3 Levels at Diagnosis and During Follow-up in Melanoma Patients

Pr Sélim ARACTINGI, Saiag P, Aegerter P, Vitoux D, Lebbé C, Wolkenstein P, Dupin N, Descamps V, Funck-Brentano E, Autier P, Dragomir M, Boniol M

J Natl Cancer Inst


BACKGROUND: A low 25-hydroxyvitamin D3 (25(OH)D3) serum concentration at melanoma diagnosis might be associated with worse survival. We prospectively studied the prognostic value of 25(OH)D3 at diagnosis and during follow-up. METHODS: MelanCohort is a cohort of invasive melanoma patients. Serum 25(OH)D3 was measured by mass spectrometry and standardized on month of blood drawn, age, sex, and body mass index (BMI). Role of 25(OH)D3 levels and risk of relapse was analyzed in a Cox proportional hazards model adjusting for age, sex, BMI, and American Joint Committee on Cancer (AJCC) stage. All statistical tests were two-sided. RESULTS: One thousand one hundred seventy-one patients were included. 25(OH)D3 levels at diagnosis (median = 49.0 nmol/L) were inversely correlated with prognostic factors such as AJCC stage (P < .001 Kruskal-Wallis), Breslow's thickness (P < .001 Spearman correlation), and ulceration (P < .001 Kruskal-Wallis), but not with risk of relapse. Changes in 25(OH)D3 levels during follow-up were associated with worse prognosis: With a third quartile Q3 of average change per year (-0.30 to 4.60 nmol/L/Y) used as reference, hazard ratios for the first, second, and fourth quarters were 1.94 (95% confidence interval [CI] = 1.36 to 2.76), 1.23 (95% CI = 0.85 to 1.78), and 1.61 (95% CI = 1.14 to 2.28), respectively. In sensitivity analyses, no changes were observed either by AJCC stage, number of 25(OH)D3 measures performed, or by 25(OH)D3 level at baseline. No evidence of reverse causation was identified. Analyses performed on overall survival yielded similar results. CONCLUSIONS: We show that 25(OH)D3 variation during follow-up is an independent melanoma prognostic marker, but not its level at diagnosis. Previously reported associations between low 25(OH)D3 level at diagnosis and poor prognosis seem to be due to insufficient adjustment for prognostic factors.