Leprosy is an infectious disease caused by non-cultivable bacteria Mycobacterium leprae. Ridley and Jopling classified the disease into five polar forms, Tuberculoid (TT) and Lepromatous (LL), in between two forms of the disease Borderline tuberculoid (BT), Borderline (BB) and Borderline lepromatous (BL) are laid. The tuberculoid type (BT/TT) leprosy patients show good recall of cellmediated immune (CMI) response and Th1 type of immune response, while lepromatous leprosy (LL) patients show defect in cell-mediated immunity to the causative agent and Th2 type of immune response. Due to distinct clinical and immunological spectra of the disease, leprosy attracted immunologists to consider an ideal model for the study of deregulations of various immune reactions. Recent studies show that Tregs, Th3 (TGF-β, IL-10), IL-35 producing Treg immune response associated with the immune suppressive environment, survival of bugs. IL-17 producing Th17 immune response associated with tuberculoid leprosy and play protective role. γδ T cells also increased from tuberculoid to lepromatous pole of leprosy. In this review, we will discuss the role of various subtypes of T-cell and their cytokines in the pathogenesis of leprosy. Keywords: Leprosy, Th1 and Th2 cells, Treg cells, pathogenesis of leprosy, tuberculoid leprosy, cytokines.
Leprosy is a chronic infectious disease caused by Mycobacterium leprae. FoxP3 have been shown to have important implications in various diseases. The present study describes the mechanism of action of FoxP3 in CD4⁺CD25⁺ T cells derived from leprosy patients. Increased molecular interactions of FoxP3 with histone deacetylases 7/9 in the nucleus of CD4⁺CD25⁺ T cells derived from borderline lepromatous leprosy/lepromatous leprosy (BL/LL) patients were found to be responsible for FoxP3-driven immune suppression activities during the progression of leprosy. Further, downregulation of CTLA-4 and CD25 genes in siFoxP3-treated PBMCs derived from BL/LL patients elucidated the transcription-activating nature of FoxP3. This observation was supported by direct binding of FoxP3 to the promoter region of the CTLA-4 and CD25 genes, and FoxP3's molecular interaction with histone acetyl transferases. The study also revealed that the increased expression of miR155 in CD4⁺CD25⁺ cells from BL/LL governs the competitive fitness of these cells. Again, reduced Annexin V & propidium iodide staining and Nur77 expression, and concomitantly increased Ki-67 positivity suggested that CD4⁺CD25⁺ cells derived from BL/LL patients are more competitively fit than those from borderline tuberculoid leprosy/tuberculoid leprosy and healthy controls. Taken together, the study shows the orchestration of FoxP3 leading to competitive fitness of Treg cells in leprosy.
Though intra-portal islet transplantation demonstrated as best suited strategy for the reversal of hyperglycemia without the threat of iatrogenic hyperglycemia in type 1 diabetes (T1D) in patients, the inferior quality of post-transplantation (tx) vascularization needs to be addressed for the maximization of post-tx islet survival. Therefore, in this study, we have first generated MSCs and endothelial progenitor cells (EPC) from mice bone marrow by in house optimized protocol and then 3-D co-cultured them with mice islets. Secretion of in the culture supernatant suggested the pro-angiogenic nature of 3D cultured mice islets. After 5 days post-tx of these pro-angiogenic islets in the omental pouch of syngeneic mice led to: 1) restoration of normoglycemia, 2) secretion of mouse C-peptide and 3) induction of angiogenic factors after 3 days of post-tx. The induction of angiogenic factors was done by RT-qPCR of omental biopsies. Importantly, pro-angiogenic islet recipient mice also demonstrated the clearance of glucose within 75 min, reflecting their efficient function and engraftment. Our results highlights needs of 3-D co-culture islets for superior quality post-tx islet vasculature and better engraftment â€" crux to improvise the challenges associated with post-tx islet vascularization and functions.
Background and Hypothesis: Hepatic stellate cells (HSC), which compromise ~15% of liver cells, are vital to hepatocellular function. Scaffold-free 3D-bioprinting (SF3DBP) offers an avenue for the creation of realistic organ models without the use of biomaterials. Therefore, we hypothesized that co-culturing primary hepatocytes with HSC in SF3DBP liver model would uphold hepatocyte function over time, providing us a better 3D-liver model for research.
Experimental Design: We used freshly thawed primary pig hepatocytes and immortalized pig HSC to generate spheroids with hepatocytes alone, HSC alone, or a combination of hepatocytes and HSC (2.5:1 ratio). Spheroids were formed using low adhesion plates, then characterized for distance from well center, diameter, roundness, and smoothness. A column of spheroids was printed using a Regenova 3D-bioprinter. Remaining loose spheroids are incubated over two weeks for albumin secretion, mRNA transcription, and histological analysis.
Results: Co-cultures of hepatocytes and HSC (2.5:1 ratio) formed spheroids within 48 hours, as did HSC only spheroids (Figure 1). Spheroids composed of only hepatocytes failed to form round spheroids. The combination spheroids increased in roundness and decreased in diameter between characterizations over 6 days.
Conclusion and Potential Impact: Spheroids proved too large to print at 48 hours but were successfully recognized and placed by the 3D-bioprinter. SF3DBP of combination spheroids would be viable by day 6. Optimization of spheroid composition using different cell ratios including HSC, hepatocytes, liver sinusoidal endothelial cells and fibroblasts, as well as optimization of spheroid incubation time will allow for production and printing of more advanced liver models.
Innate immune response is regulated by tissue resident or infiltrating immune cells such as macrophages (Mφ) that play critical role in tissue development, homeostasis, and repair of damaged tissue. However, the epigenetic mechanisms that regulate Mφ plasticity and innate immune functions are not well understood. Long non-coding RNA (lncRNA) are among the most abundant class of transcriptome but their function in myeloid cell biology is less explored. In this study, we deciphered the regulatory role of previously uncharacterized lncRNAs in Mφ polarization and innate immune responses. Two lncRNAs showed notable changes in their levels during M1 and M2 Mφ differentiation. Our findings indicate that LINC01010 expression increased and AC007032 expression decreased significantly. LINC01010 exhibit myeloid cell-specificity, while AC007032.1 is ubiquitous and expressed in both myeloid and lymphoid (T cells, B cells and NK cells) cells. Expression of these lncRNAs is dysregulated in periodontal disease (PD), a microbial biofilm-induced immune disease, and responsive to lipopolysaccharide (LPS) from different oral and non-oral bacteria. Knockdown of LINC01010 but not AC007032.1 reduced the surface expression of Mφ differentiation markers CD206 and CD68, and M1Mφ polarization markers MHCII and CD32. Furthermore, LINC01010 RNAi attenuated bacterial phagocytosis, antigen processing and cytokine secretion suggesting its key function in innate immunity. Mechanistically, LINC01010 knockdown Mφ treated with Escherichia coli LPS exhibit significantly reduced expression of multiple nuclear factor kappa B pathway genes. Together, our data highlight functional role of a PD-associated lncRNA LINC01010 in shaping macrophage differentiation, polarization, and innate immune activation.
Macrophages (Mφ) are long-lived myeloid cells that can polarize towards the proinflammatory M1 or proresolving M2 phenotype to control diverse biological processes such as inflammation, tissue damage, and regeneration. Noncoding RNA are a class of nonprotein-coding transcriptome with numerous interdependent biological roles; however, their functional interaction in the regulation of Mφ polarization and immune responses remain unclear. Here, we show antagonistic relationship between lncRNA (MALAT1) and microRNA (miR-30b) in shaping macrophage polarization and immune functions. MALAT1 expression displays a time-dependent induction during Mφ differentiation and, upon challenge with TLR4 agonist (E. coli LPS). MALAT1 knockdown promoted the expression of M2Mφ markers without affecting M1Mφ markers, suggesting that MALAT1 favors the M1 phenotype by suppressing M2 differentiation. Compared to the control, MALAT1 knockdown resulted in reduced antigen uptake and processing, bacterial phagocytosis, and bactericidal activity, strongly supporting its critical role in regulating innate immune functions in Mφ. Consistent with this, MALAT1 knockdown showed impaired cytokine secretion upon challenge with LPS. Importantly, MALAT1 exhibit an antagonistic expression pattern with all five members of the miR-30 family during M2 Mφ differentiation. Dual-luciferase assays validated a novel sequence on MALAT1 that interacts with miR-30b, a microRNA that promotes the M2 phenotype. Phagocytosis and antigen processing assays unequivocally demonstrated that MALAT1 and miR-30b are functionally antagonistic. Concurrent MALAT1 knockdown and miR-30b overexpression exhibited the most significant attenuation in both assays. In human subjects with periodontal disease and murine model of ligature-induced periodontitis, we observed higher levels of MALAT1, M1Mφ markers and downregulation of miR-30b expression in gingival tissues suggesting a pro-inflammatory function of MALAT1 in vivo . Overall, we unraveled the role of MALAT1 in Mφ polarization and delineated the underlying mechanism of its regulation by involving MALAT-1-driven miR-30b sequestration.
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