Correlation between nerve growth factor and tissue expression of IL-17 in leprosy.

Leprosy is a serious public health problem in peripheral and developing countries. Leprosy is a chronic infectious-contagious disease caused by the intracellular, bacillus Mycobacterium leprae, which causes tissue damage and demyelination of peripheral nerves. Recent studies have demonstrated the participation of new subtype's cytokines profile in the inflammatory response of leprosy. Since nerve functions are affected by inflammatory response during the course of leprosy, changes in the production of NGF and its receptor (NGF R) may be directly associated with disability and sensory loss. Skin biopsies were collected and submitted to immunohistochemistry using specific antibodies to IL-17, NGF and NGF R. Quantitative analysis of NGF, NGFR and IL-17 immunostaining showed a significant difference between the clinical forms, with higher expression of NGF and NGFR in lepromatous leprosy and IL-17 in tuberculoid leprosy. The present study showed that IL-17, in addition to stimulating an inflammatory response, negatively regulates the action of NGF and NGF R in the polar forms of the disease.

Distinctive contact between CD34+ hematopoietic progenitors and CXCL12+ CD271+ mesenchymal stromal cells in benign and myelodysplastic bone marrow.

Mesenchymal stromal cells (MSCs) support hematopoiesis and are cytogenetically and functionally abnormal in myelodysplastic syndrome (MDS), implying a possible pathophysiologic role in MDS and potential utility as a diagnostic or risk-stratifying tool. We have analyzed putative MSC markers and their relationship to CD34+ hematopoietic stem/progenitor cells (HSPCs) within intact human bone marrow in paraffin-embedded bone marrow core biopsies of benign, MDS and leukemic (AML) marrows using tissue microarrays to facilitate scanning, image analysis and quantitation. We found that CD271+, ALP+ MSCs formed an extensive branching perivascular, periosteal and parenchymal network. Nestin was brightly positive in capillary/arteriolar endothelium and occasional subendothelial cells, whereas CD146 was most brightly expressed in SMA+ vascular smooth muscle/pericytes. CD271+ MSCs were distinct by double immunofluorescence from CD163+ macrophages and were in close contact with but distinct from brightly nestin+ and from brightly CD146+ vascular elements. Double immunofluorescence revealed an intimate spatial relationship between CD34+ HSPCs and CD271+ MSCs; remarkably, 86% of CD34+ HSPCs were in direct contact with CD271+ MSCs across benign, MDS and AML marrows, predominantly in a perivascular distribution. Expression of the intercrine chemokine CXCL12 was strong in the vasculature in both benign and neoplastic marrow, but was also present in extravascular parenchymal cells, particularly in MDS specimens. We identified these parenchymal cells as MSCs by ALP/CXCL12 and CD271/CXCL12 double immunofluorescence. The area covered by CXCL12+ ALP+ MSCs was significantly greater in MDS compared with benign and AML marrow (P=0.021, Kruskal-Wallis test). The preservation of direct CD271+ MSC/CD34+ HSPC contact across benign and neoplastic marrow suggests a physiologically important role for the CD271+ MSC/CD34+ HSPC relationship and possible abnormal exposure of CD34+ HSPCs to increased MSC CXCL12 expression in MDS.

Supraorganized collagen enhances Schwann cell reactivity and organization in vitro.

We investigated the reactivity and expression of basal lamina collagen by Schwann cells (SCs) cultivated on a supraorganized bovine-derived collagen substrate. SC cultures were obtained from sciatic nerves of neonatal Sprague-Dawley rats and seeded on 24-well culture plates containing collagen substrate. The homogeneity of the cultures was evaluated with an SC marker antibody (anti-S-100). After 1 week, the cultures were fixed and processed for immunocytochemistry by using antibodies against type IV collagen, S-100 and p75NTR (pan neurotrophin receptor) and for scanning electron microscopy (SEM). Positive labeling with antibodies to the cited molecules was observed, indicating that the collagen substrate stimulates SC alignment and adhesion (collagen IV labeling - organized collagen substrate: 706.33 ± 370.86, non-organized collagen substrate: 744.00 ± 262.09; S-100 labeling - organized collagen: 3809.00 ± 120.28, non-organized collagen: 3026.00 ± 144.63, P < 0.05) and reactivity (p75NTR labeling - organized collagen: 2156.33 ± 561.78, non-organized collagen: 1424.00 ± 405.90, P < 0.05; means ± standard error of the mean in absorbance units). Cell alignment and adhesion to the substrate were confirmed by SEM analysis. The present results indicate that the collagen substrate with an aligned suprastructure, as seen by polarized light microscopy, provides an adequate scaffold for SCs, which in turn may increase the efficiency of the nerve regenerative process after in vivo repair.

Supraorganized collagen enhances Schwann cell reactivity and organization in vitro

We investigated the reactivity and expression of basal lamina collagen by Schwann cells (SCs) cultivated on a supraorganized bovine-derived collagen substrate. SC cultures were obtained from sciatic nerves of neonatal Sprague-Dawley rats and seeded on 24-well culture plates containing collagen substrate. The homogeneity of the cultures was evaluated with an SC marker antibody (anti-S-100). After 1 week, the cultures were fixed and processed for immunocytochemistry by using antibodies against type IV collagen, S-100 and p75NTR (pan neurotrophin receptor) and for scanning electron microscopy (SEM). Positive labeling with antibodies to the cited molecules was observed, indicating that the collagen substrate stimulates SC alignment and adhesion (collagen IV labeling - organized collagen substrate: 706.33 ± 370.86, non-organized collagen substrate: 744.00 ± 262.09; S-100 labeling - organized collagen: 3809.00 ± 120.28, non-organized collagen: 3026.00 ± 144.63, P < 0.05) and reactivity (p75NTR labeling - organized collagen: 2156.33 ± 561.78, non-organized collagen: 1424.00 ± 405.90, P < 0.05; means ± standard error of the mean in absorbance units). Cell alignment and adhesion to the substrate were confirmed by SEM analysis. The present results indicate that the collagen substrate with an aligned suprastructure, as seen by polarized light microscopy, provides an adequate scaffold for SCs, which in turn may increase the efficiency of the nerve regenerative process after in vivo repair.

The involvement of CD4+CD25+ T cells in the acute phase of Trypanosoma cruzi infection.

The infection with Trypanosoma cruzi leads to a vigorous and apparently uncontrolled inflammatory response in the heart. Although the parasites trigger specific immune response, the infection is not completely cleared out, a phenomenon that in other parasitic infections has been attributed to CD4+CD25+ T cells (Tregs). Then, we examined the role of natural Tregs and its signaling through CD25 and GITR in the resistance against infection with T. cruzi. Mice were treated with mAb against CD25 and GITR and the parasitemia, mortality and heart pathology analyzed. First, we demonstrated that CD4+CD25+GITR+Foxp3+ T cells migrate to the heart of infected mice. The treatment with anti-CD25 or anti-GITR resulted in increased mortality of these infected animals. Moreover, the treatment with anti-GITR enhanced the myocarditis, with increased migration of CD4+, CD8+, and CCR5+ leukocytes, TNF-alpha production, and tissue parasitism, although it did not change the systemic nitric oxide synthesis. These data showed a limited role for CD25 signaling in controlling the inflammatory response during this protozoan infection. Also, the data suggested that signaling through GITR is determinant to control of the heart inflammation, parasite replication, and host resistance against the infection.

Astrocyte activation by fibroblast growth factor-1 and motor neuron apoptosis: implications for amyotrophic lateral sclerosis.

Fibroblast growth factor-1 (FGF1 or acidic FGF) is highly expressed in motor neurons. FGF-1 is released from cells by oxidative stress, which might occur from SOD-1 aberrant function in amyotrophic lateral sclerosis (ALS). Although FGF-1 is known to be neuroprotective after spinal cord injury or axotomy, we found that FGF-1 could activate spinal cord astrocytes in a manner that decreased motor neuron survival in co-cultures. FGF-1 induced accumulation of the FGF receptor 1 (FGFR1) in astrocyte nuclei and potently stimulated nerve growth factor (NGF) expression and secretion. The FGFR1 tyrosine kinase inhibitor PD166866 prevented these effects. Previously, we have shown that NGF secretion by reactive astrocytes induces motor neuron apoptosis through a p75(NTR)-dependent mechanism. Embryonic motor neurons co-cultured on the top of astrocytes exhibiting activated FGFR1 underwent apoptosis, which was prevented by PD166866 or by adding either anti-NGF or anti-p75(NTR) neutralizing antibodies. In the degenerating spinal cord of mice carrying the ALS mutation G93A of Cu, Zn superoxide dismutase, FGF-1 was no longer localized only in the cytosol of motor neurons, while FGFR1 accumulated in the nuclei of reactive astrocytes. These results suggest that FGF-1 released by oxidative stress from motor neurons might have a role in activating astrocytes, which could in turn initiate motor neuron apoptosis in ALS through a p75(NTR)-dependent mechanism.