M2-Polarized Macrophages Determine Human Cutaneous Lesions in Lacaziosis

Macrophage immunophenotypes in Jorge Lobo's disease and lepromatous leprosy- A comparative study

Jorge Lobo's disease (JLD) and lepromatous leprosy (LL) share several clinical, histological and immunological features, especially a deficiency in the cellular immune response. Macrophages participate in innate and adaptive inflammatory immune responses, as well as in tissue regeneration and repair. Macrophage function deficiency results in maintenance of diseases. M1 macrophages produce pro-inflammatory mediators and M2 produce anti-inflammatory cytokines. To better understand JLD and LL pathogenesis, we studied the immunophenotype profile of macrophage subtypes in 52 JLD skin lesions, in comparison with 16 LL samples, using a panmacrophage (CD68) antibody and selective immunohistochemical markers for M1 (iNOS) and M2 (CD163, CD204) responses, HAM56 (resident/fixed macrophage) and MAC 387 (recently infiltrating macrophage) antibodies. We found no differences between the groups regarding the density of the CD163, CD204, MAC387+ immunostained cells, including iNOS, considered a M1 marker. But HAM56+ cell density was higher in LL samples. By comparing the M2 and M1 immunomarkers in each disease separately, some other differences were found. Our results reinforce a higher M2 response in JLD and LL patients, depicting predominant production of anti-inflammatory cytokines, but also some distinction in degree of macrophage activation. Significant amounts of iNOS + macrophages take part in the immune milieu of both LL and JLD samples, displaying impaired microbicidal activity, like alternatively activated M2 cells.

Transcription factor c-Maf drives macrophages to promote hypertrophic scar formation

BACKGROUND

Hypertrophic scar (HS) is caused by the abnormal proliferation of fibroblasts and excessive deposition of extracellular matrix (ECM). Emerging evidence demonstrates that c-Maf positive M2 macrophages were mainly located in the hypertrophic scar tissues of proliferative phase. But whether c-Maf positive M2 macrophages can promote hypertrophic scar formation through modulating hypertrophic scar fibroblasts remains elusive.

AIMS

The aim of this study is to investigate the effects of c-Maf positive M2 macrophages on the biological behaviors and functions of hypertrophic scar fibroblasts and the potential mechanism.

METHODS

HE and Masson trichrome staining were used to examine the histological features of human hypertrophic scar. Immunofluorescence staining was employed to label and quantify the c-Maf+ /CD68+ M2 macrophages. CCK8, wound healing, and transwell assays were utilized to test the effects of c-Maf overexpressed M2 macrophages or the cell culture supernatants on the proliferation and migration of hypertrophic scar derived fibroblasts (HFBs) and normal skin derived fibroblasts (NFBs). Western blot and qPCR were harnessed to test the expressions of COL1, COL3, and α-SMA in the co-cultivated fibroblasts and TGF-β1 in the c-Maf overexpressed M2 macrophages.

RESULTS

Increased number of c-Maf+ /CD68+ M2 macrophages were found in HS in contrast to the normal skin (NS). Elevated proliferation and migration were observed in the HFBs or NFBs co-cultured with c-Maf overexpressed macrophages or the cell culture supernatants. A higher mRNA and protein expressions of COL1, COL3, and α-SMA were recorded in the HFBs co-cultured with c-Maf overexpressed macrophages or treated with its culture supernatants. In addition, augmented mRNA and protein expressions of TGF-β1 were also investigated in the c-Maf overexpressed macrophages.

CONCLUSION

c-Maf positive macrophages promote hypertrophic scar formation through regulating HFBs proliferation, migration, and ECM deposition via the secreted TGF-β1.

All-Trans Retinoic Acid Promotes M2 Macrophage Polarization in Vitro by Activating the p38MAPK/STAT6 Signaling Pathway

BACKGROUND

M2-type macrophages are inflammation-suppressing cells that are differentiated after induction by cytokines such as IL-4 or IL-13, which play an important regulatory role in inflammation and influence the regression of inflammation-related diseases. All-trans retinoic acid (ATRA) has an important role in suppressing immune-mediated inflammatory responses but the effect and underlying mechanism of ATRA on the polarization of M2 macrophages remains unclear.

METHODS

Macrophages were isolated from peritoneal wash fluid, and IL-4 (20 ng/mL) was used to construct a m2-type macrophage polarization model. The model was incubated with different concentrations of ATRA (15 µg/ml, 30 µg/ml, 45 µg/ml) for 24 h, and pretreated macrophages with p38MAPKα inhibitor SB202190 (20 μM). MTT, Trypan blue staining, Annexin V-PE/7-AAD staining, flow cytometry, real-time PCR and western blotting were used to investigate the effect and mechanism of ATRA on the polarization of M2 macrophages.

RESULTS

Compared with the IL-4 group, the proportion of F4/80⁺CD206⁺ M2-type macrophages was significantly higher in the ATRA group (P < 0.01). mRNA and protein expression levels of Arg-1, IL-10 and TGF-β1 were as significantly higher (P < 0.01) in the ATRA group as phosphorylation levels of STAT6 and p38MAPK (P < 0.01). After pretreatment with the addition of the inhibitor SB202190, M2-type macrophages proportion and their associated factors expression were significantly (P < 0.01) reduced, as compared with those in the ATRA group, but they were comparable (P > 0.05) with the IL-4 group.

CONCLUSION

The combination of ATRA and IL-4 activated the p38MAPK/STAT6-signaling pathway to promote polarization of M2 macrophages.

Mycetoma, chromoblastomycosis and other deep fungal infections: diagnostic and treatment approach

PURPOSE OF REVIEW

to review recent advances in the epidemiology, diagnosis, and treatment of deep fungal infections.

RECENT FINDINGS

Mycetoma and chromoblastomycosis are the only deep fungal infections incorporated in the list of neglected tropical diseases. These infections start in the skin but progress to deep tissues if not recognized early. A wide array of fungal pathogens are the causative agents. Molecular methods allow for early and accurate identification of the pathogens, but are unfortunately not available in endemic areas. Treatment options are mostly based upon clinical experience rather than on well-designed clinical trials.

SUMMARY

Deep fungal infections of the skin and soft tissues are rare conditions of wide world distribution but mostly reported from tropical countries. Urgent need for affordable and easily accessible molecular methods and well-conducted studies to allow for accurate diagnosis and to provide evidence to guide proper therapy are urgently needed.