Immunophenotypical characterization of macrophages in rat bleomycin-induced scleroderma

The therapeutic potential of galectin-3 inhibition in fibrotic disease

Galectin-3 is a beta-galactoside-binding mammalian lectin and part of the 15 member galectin family that are evolutionarily highly conserved. It is the only chimeric protein with a C-terminal carbohydrate recognition domain (CRD) linked to a proline, glycine, and tyrosine rich additional N-terminal domain. Galectin-3 binds several cell surface glycoproteins via its CRD domain as well as undergoing oligomerization, via binding at the N-terminal or the CRD, resulting in the formation of a galectin-3 lattice on the cell surface. The galectin-3 lattice has been regarded as being a crucial mechanism whereby extracellular galectin-3 modulates cellular signalling by prolonging retention time or retarding lateral movement of cell surface receptors in the plasma membrane. As such galectin-3 can regulate various cellular functions such as diffusion, compartmentalization and endocytosis of plasma membrane glycoproteins and glycolipids and the functionality of membrane receptors. In multiple models of organ fibrosis, it has been demonstrated that galectin-3 is potently pro-fibrotic and modulates the activity of fibroblasts and macrophages in chronically inflamed organs. Increased galectin-3 expression also activates myofibroblasts resulting in scar formation and may therefore impact common fibrotic pathways leading to fibrosis in multiple organs. Over the last decade there has been a marked increase in the scientific literature investigating galectin-3 in a range of fibrotic diseases as well as the clinical development of new galectin-3 inhibitors. In this review we will examine the role of galectin-3 in fibrosis, the therapeutic strategies for inhibiting galectin-3 in fibrotic disease and the clinical landscape to date.

The expression and function of galectins in skin physiology and pathology

The galectin family comprises β-galactoside-binding proteins widely expressed in many organisms. There are at least 16 family members, which can be classified into three groups based on their carbohydrate-recognition domains. Pleiotropic functions of different galectins in physiological and pathological processes through extracellular or intracellular actions have been revealed. In the skin, galectins are expressed in a variety of cells, including keratinocytes, melanocytes, fibroblasts, dendritic cells, lymphocytes, macrophages and endothelial cells. Expression of specific galectins is reported to affect cell status, such as activation or death, and regulate the interaction between different cell types or between cells and the extracellular matrix. In vitro cellular studies, in vivo animal studies and studies of human clinical material have revealed the pathophysiologic roles of galectins in the skin. The pathogenesis of diverse non-malignant skin disorders, such as atopic dermatitis, psoriasis, contact dermatitis and wound healing, as well as skin cancers, such as melanoma, squamous cell carcinoma, basal cell carcinoma and cutaneous haematologic malignancy can be regulated by different galectins. Revelation of biological roles of galectins in skin may pave the way to future development of galectin-based therapeutic strategies for skin diseases.

Wound Healing in Streptozotocin-Induced Diabetic Rats Using Atmospheric-Pressure Argon Plasma Jet

In this study, we used an argon-based round atmospheric-pressure plasma jet (APPJ) for enhancing wound healing in streptozotocin (STZ) induced diabetic rats. The APPJ was characterized by optical emission spectroscopy. We induced Type 1 and Type 2 diabetes in rats with different amounts of STZ combined with normal and high-fat diets, respectively. The wound area ratio of all the plasma-treated normal and diabetic groups was greatly reduced (up to 30%) compared with that of the untreated groups during healing. Histological analysis revealed faster re-epithelialization, collagen deposition, less inflammation, and a complete skin structure in the plasma-treated groups was found as compared with the untreated control groups. In addition, the new blood vessels of plasma-treated tissues decreased more than untreated tissues in the middle (Day 14) and late (Day 21) stages of wound healing. The plasma-treated wounds demonstrated more transforming growth factor beta (TGF-β) expression in the early stage (Day 7), whereas they decreased in the middle and late stages of wound healing. The levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) increased after plasma treatment. In addition, plasma-treated water had a higher concentration of hydrogen peroxide, nitrite and nitrate when the plasma treatment time was longer. In summary, the proposed argon APPJ based on the current study could be a potential tool for treating diabetic wounds.

Histopathological Analysis of Rat Hepatotoxicity Based on Macrophage Functions: in Particular, an Analysis for Thioacetamide-induced Hepatic Lesions

Hepatic macrophages play an important role in homeostasis. The functional abnormalities of hepatic macrophages primarily or secondarily influence chemically induced hepatotoxicity. However, the evaluation system based on their functions has not yet been established. Recently, a new concept (M1-/M2-macrophage polarization) was proposed; M1-macropahges are induced by INF-γ, and show high phagocytosis/tissue damage, whereas M2-macropahges are induced by IL-4 and play roles in reparative fibrosis by releasing IL-10 and TGF-β1. In hepatogenesis, CD68-expressing M1-macrophages predominantly exist in embryos; in neonates, in contrast, CD163-/CD204-expressing M2-macrophages appear along the sinusoids and mature as Kupffer cells. Activated Kupffer cells by liposome decrease AST and ALT values, whereas AST and ALT values are increased under Kupffer cells depleted with clodronate treatment. Since Kupffer cells may be involved in clearance of liver enzymes, macrophage condition should be taken into consideration when hepatotoxicity is analyzed. In TAA-induced acute hepatic lesions, INF-γ, TNF-α and IL-6 for M1-factors and IL-4 for M2-factors are already increased before histopathological change; the appearance of CD68-expressing M1-macrophages and CD163-expressing M2-macrophages follows in injured centrilobular lesions, and TGF-β1 and IL-10 are increased for reparative fibrosis. CD68-expressing M1-macrophages co-express MHC class II and Iba-1, whereas CD163-expressing M2-macrophages also express CD204 and Galectin-3. Under macrophage depletion by clodoronate, TAA-treated rat livers show prolonged coagulation necrosis of hepatocytes, and then develop dystrophic calcification without reparative fibrosis. The depletion of hepatic macrophages influences hepatic lesion development. Collectively, a histopathological analysis method for hepatotoxicity according to M1-/M2-macrophage polarization would lead to the refinement of hazard characterization of chemicals in food and feed.

Parallel Aspects of the Microenvironment in Cancer and Autoimmune Disease

Cancer and autoimmune diseases are fundamentally different pathological conditions. In cancer, the immune response is suppressed and unable to eradicate the transformed self-cells, while in autoimmune diseases it is hyperactivated against a self-antigen, leading to tissue injury. Yet, mechanistically, similarities in the triggering of the immune responses can be observed. In this review, we highlight some parallel aspects of the microenvironment in cancer and autoimmune diseases, especially hypoxia, and the role of macrophages, neutrophils, and their interaction. Macrophages, owing to their plastic mode of activation, can generate a pro- or antitumoral microenvironment. Similarly, in autoimmune diseases, macrophages tip the Th1/Th2 balance via various effector cytokines. The contribution of neutrophils, an additional plastic innate immune cell population, to the microenvironment and disease progression is recently gaining more prominence in both cancer and autoimmune diseases, as they can secrete cytokines, chemokines, and reactive oxygen species (ROS), as well as acquire an enhanced ability to produce neutrophil extracellular traps (NETs) that are now considered important initiators of autoimmune diseases. Understanding the contribution of macrophages and neutrophils to the cancerous or autoimmune microenvironment, as well as the role their interaction and cooperation play, may help identify new targets and improve therapeutic strategies.

CSF-1-dependant donor-derived macrophages mediate chronic graft-versus-host disease

Chronic GVHD (cGVHD) is the major cause of late, nonrelapse death following stem cell transplantation and characteristically develops in organs such as skin and lung. Here, we used multiple murine models of cGVHD to investigate the contribution of macrophage populations in the development of cGVHD. Using an established IL-17-dependent sclerodermatous cGVHD model, we confirmed that macrophages infiltrating the skin are derived from donor bone marrow (F4/80+CSF-1R+CD206+iNOS-). Cutaneous cGVHD developed in a CSF-1/CSF-1R-dependent manner, as treatment of recipients after transplantation with CSF-1 exacerbated macrophage infiltration and cutaneous pathology. Additionally, recipients of grafts from Csf1r-/- mice had substantially less macrophage infiltration and cutaneous pathology as compared with those receiving wild-type grafts. Neither CCL2/CCR2 nor GM-CSF/GM-CSFR signaling pathways were required for macrophage infiltration or development of cGVHD. In a different cGVHD model, in which bronchiolitis obliterans is a prominent manifestation, F4/80+ macrophage infiltration was similarly noted in the lungs of recipients after transplantation, and lung cGVHD was also IL-17 and CSF-1/CSF-1R dependent. Importantly, depletion of macrophages using an anti-CSF-1R mAb markedly reduced cutaneous and pulmonary cGVHD. Taken together, these data indicate that donor macrophages mediate the development of cGVHD and suggest that targeting CSF-1 signaling after transplantation may prevent and treat cGVHD.

Immunohistochemical Characterization and Morphometric Analysis of Macrophages in Rat Mammary Tumors

Macrophages are an important leukocyte component of the microenvironment of neoplasms. Macrophages have classically been subdivided into M1 and M2, depending on their roles in immune response, wound healing, and promotion or inhibition of tumor growth. In human breast cancer, increased presence of M2 macrophages has been associated with poor prognosis. The authors hypothesized that rat mammary carcinomas have increased macrophage influx compared to benign mammary proliferative lesions and normal mammary glands as well. In humans, both M1 and M2 macrophages express CD68, while CD163 is expressed primarily by M2 macrophages. Based on a single immunolabeling protocol with anti-CD68 and anti-CD163 antibodies, the extent of macrophage influx was investigated by morphometry to quantitate the immunopositive cells in normal rat mammary glands, benign mammary proliferative lesions, and mammary carcinomas. In mammary carcinomas, there was significantly higher percentage of CD68+ cells compared to benign mammary proliferative lesions and normal mammary glands. There was also higher percentage of CD163+ cells in mammary carcinomas compared to benign mammary proliferative lesions. Thus, increase in CD68+ and CD163+ macrophages corresponded to increased malignancy of rat mammary tumors in this study.