Chemokines in Leishmaniasis: Map of cell movements highlights the landscape of infection and pathogenesis

Memory T Cell Subsets Expressing Tissue Homing Receptors and Chemokine Levels in Human Tegumentary Leishmaniasis

Tegumentary leishmaniasis (TL) presents two main clinical forms: cutaneous (CL) and mucosal (ML) leishmaniasis affecting skin and nasopharyngeal mucosa. Due to parasite localization through disease stages, recruitment of T cells expressing chemokine receptors and their ligands will influence the generated host responses. The aim of this work was to characterize differential profiles of T cells expressing chemokine receptors and their plasma ligands by flow cytometry and ELISA. CL patients showed increased numbers of effector memory CD4+ T cells expressing skin homing receptors (CLA, CCR4), with the reversion of this effector phenotype observed after achieving clinical recovery. Meanwhile, ML patients showed higher frequencies of effector memory/terminal effector CD4+ and CD8+ T cells expressing chemokine receptors directed to skin (CLA, CCR4, CCR10) and mucosal (CCR6) tissues. Additionally, we reported that plasma amounts of ligands (CCL17, CCL20) vary according to the clinical form of TL. Finally, we demonstrated the ability of Leishmania spp. to modulate chemokine production (CCL17) in vitro. This work highlights the effector T cell response directed to skin and mucosal tissues in TL, emphasizing the role of cytotoxic functions in ML. The studied chemokine receptors could contribute to predicting disease progression and guiding future studies targeting relevant receptors to diminish pathogenic effector functions.

Determination of key hub genes in Leishmaniasis as potential factors in diagnosis and treatment based on a bioinformatics study

Leishmaniasis is an infectious disease caused by protozoan parasites from different species of leishmania. The disease is transmitted by female sandflies that carry these parasites. In this study, datasets on leishmaniasis published in the GEO database were analyzed and summarized. The analysis in all three datasets (GSE43880, GSE55664, and GSE63931) used in this study has been performed on the skin wounds of patients infected with a clinical form of leishmania (Leishmania braziliensis), and biopsies have been taken from them. To identify differentially expressed genes (DEGs) between leishmaniasis patients and controls, the robust rank aggregation (RRA) procedure was applied. We performed gene functional annotation and protein-protein interaction (PPI) network analysis to demonstrate the putative functionalities of the DEGs. The study utilized Molecular Complex Detection (MCODE), Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) to detect molecular complexes within the protein-protein interaction (PPI) network and conduct analyses on the identified functional modules. The CytoHubba plugin's results were paired with RRA analysis to determine the hub genes. Finally, the interaction between miRNAs and hub genes was predicted. Based on the RRA integrated analysis, 407 DEGs were identified (263 up-regulated genes and 144 down-regulated genes). The top three modules were listed after creating the PPI network via the MCODE plug. Seven hub genes were found using the CytoHubba app and RRA: CXCL10, GBP1, GNLY, GZMA, GZMB, NKG7, and UBD. According to our enrichment analysis, these functional modules were primarily associated with immune pathways, cytokine activity/signaling pathways, and inflammation pathways. However, a UBD hub gene is interestingly involved in the ubiquitination pathways of pathogenesis. The mirNet database predicted the hub gene's interaction with miRNAs, and results revealed that several miRNAs, including mir-146a-5p, crucial in fighting pathogenesis. The key hub genes discovered in this work may be considered as potential biomarkers in diagnosis, development of agonists/antagonist, novel vaccine design, and will greatly contribute to clinical studies in the future.

Evaluation of Chemokines MIG and IP-10 as Immunological Biomarkers of Human Visceral Leishmaniasis: A Systematic Review

Visceral leishmaniasis (VL) is a neglected tropical disease that is potentially fatal when untreated. Current diagnostic methods have limitations that contribute to ongoing transmission and poor prognosis. Thus, new tests are needed to provide quick, accurate diagnoses and evaluate clinical progression and treatment efficacy. The monokine induced by interferon-gamma (MIG) and interferon-gamma-inducible protein 10 (IP-10) has been associated with the host susceptibility to VL with potential diagnostic and prognostic purposes. We performed a systematic review using four search databases (Scopus, PubMed, Web of Science, and MEDLINE) to identify studies assessing MIG and IP-10 as potential biomarkers in patients with VL across various clinical conditions. A total of 13 studies were potentially eligible and included in this review. The articles, in general, reveal that the chemokines MIG and IP-10 are elevated in response to infection by Leishmania spp., acting on the host's resistance to the development of the disease. They are associated with asymptomatic conditions and after VL treatment, and this relationship can be observed in both immunocompetent and immunocompromised individuals. Consequently, these chemokines hold relevance in the diagnoses and appropriate management of individuals with VL.

An integrated bioinformatic analysis of microarray datasets to identify biomarkers and miRNA-based regulatory networks in leishmaniasis

Micro RNAs (miRNAs, miRs) and relevant networks might exert crucial functions during differential host cell infection by the different Leishmania species. Thus, a bioinformatic analysis of microarray datasets was developed to identify pivotal shared biomarkers and miRNA-based regulatory networks for Leishmaniasis. A transcriptomic analysis by employing a comprehensive set of gene expression profiling microarrays was conducted to identify the key genes and miRNAs relevant for Leishmania spp. infections. Accordingly, the gene expression profiles of healthy human controls were compared with those of individuals infected with Leishmania mexicana, L. major, L. donovani, and L. braziliensis. The enrichment analysis for datasets was conducted by utilizing EnrichR database, and Protein-Protein Interaction (PPI) network to identify the hub genes. The prognostic value of hub genes was assessed by using receiver operating characteristic (ROC) curves. Finally, the miRNAs that interact with the hub genes were identified using miRTarBase, miRWalk, TargetScan, and miRNet. Differentially expressed genes were identified between the groups compared in this study. These genes were significantly enriched in inflammatory responses, cytokine-mediated signaling pathways and granulocyte and neutrophil chemotaxis responses. The identification of hub genes of recruited datasets suggested that TNF, SOCS3, JUN, TNFAIP3, and CXCL9 may serve as potential infection biomarkers and could deserve value as prognostic biomarkers for leishmaniasis. Additionally, inferred data from miRWalk revealed a significant degree of interaction of a number of miRNAs (hsa-miR-8085, hsa-miR-4673, hsa-miR-4743-3p, hsa-miR-892c-3p, hsa-miR-4644, hsa-miR-671-5p, hsa-miR-7106-5p, hsa-miR-4267, hsa-miR-5196-5p, and hsa-miR-4252) with the majority of the hub genes, suggesting such miRNAs play a crucial role afterwards parasite infection. The hub genes and hub miRNAs identified in this study could be potentially suggested as therapeutic targets or biomarkers for the management of leishmaniasis.

Schistosoma and Leishmania: An Untold Story of Coinfection

A remarkable characteristic of infectious diseases classified as Neglected Tropical Diseases (NTDs) is the fact that they are mostly transmitted in tropical and subtropical regions with poor conditions of sanitation and low access to healthcare, which makes transmission areas more likely to overlap. Two of the most important NTDs, schistosomiasis and leishmaniasis, despite being caused by very different etiological agents, have their pathogenesis heavily associated with immune-mediated mechanisms, and Schistosoma spp. and Leishmania spp. have been shown to simultaneously infect humans. Still, the consequences of Schistosoma-Leishmania coinfections remain underexplored. As the inflammatory processes elicited by each one of these parasites can influence the other, several changes have been observed due to this coinfection in naturally infected humans, experimental models, and in vitro cell assays, including modifications in susceptibility to infection, pathogenesis, prognostic, and response to treatment. Herein, we review the current knowledge in Schistosoma-Leishmania coinfections in both human populations and experimental models, with special regard to how schistosomiasis affects tegumentary leishmaniasis, discuss future perspectives, and suggest a few steps to further improve our understanding in this model of parasite-host-parasite interaction.

The Treatment Based on Ruxolitinib and Amphotericin B is Effective for Relapsed Leishmaniasis-Related Hemophagocytic Lymphohistiocytosis: A Case Report and Literature Review

BACKGROUND

Hemophagocytic lymphohistiocytosis (HLH) is known as a life-threatening syndrome, and Leishmania is the most common protozoan that triggers infection-related HLH. It is thus important to find the root cause and treat it effectively.

CASE REPORT

This paper reports a 44-year-old man who developed antisynthetase antibody syndrome previously. The patient progressed rapidly to the extent of meeting the HLH-2004 diagnostic criteria, despite the unknown etiology. Although the patient was promptly treated in line with the HLH-1994 protocol to achieve remission, he still relapsed after glucocorticoid reduction. Afterwards, it was found out that HLH was secondary to Leishmania infection. The symptoms of HLH were alleviated quickly by the treatment with Ruxolitinib and Amphotericin B.

CONCLUSION

Etiological screening plays a crucial role in leishmaniasis-related HLH. An experienced pathologist and real-time PCR are essential for treating Leishmania. The treatment of Ruxolitinib and Amphotericin B proved effective in alleviating the relapse of visceral leishmaniasis-related HLH.

Identification of thrombin as a key regulator of chondrocyte catabolic activity through RNA-Seq and experimental verification

The present study was designed to explore the relationship between thrombin and catabolic activity in chondrocytes. Primary rat chondrocytes were cultured for 24 h with rat serum (RS), rat plasma (RP), or rat plasma supplemented with thrombin (RPT). RNA-sequencing was then performed. Cell proliferation was analyzed by EdU uptake, CCK-8 assays and protein-protein interaction (PPI) network of proliferation-related genes. Heatmaps were used to visualize differences in gene expression. Gene Ontology (GO) enrichment analyses of up- and down-regulated differentially expressed genes were conducted. Molecular probes were used to label the endoplasmic reticulum in chondrocytes from three treatment groups. Immunofluorescence and Safranin O staining were used to assess type II collagen (Col2a1) expression and proteoglycan synthesis, whereas Lox expression was assessed by immunocytochemistry. The expression of enzymes involved in the synthesis and maturation of extracellular matrix (ECM) components and chemokines were measured by qPCR while matrix metalloproteinases (MMPs) levels were evaluated by Western blotting. Relevant nodules were selected through further PPI network analyses. A total of 727 and 1162 genes were up- and down-regulated based on the Venn diagrams comparison among groups. Thrombin was thus able to promote chondrocyte proliferation and a shift towards fibrotic morphology, while upregulating MMPs and chemokines linked to ECM degradation. In addition, thrombin decreased the enzyme expression involved in the synthesis and maturation of ECM.

Role of Chemokines in the Pathogenesis of Visceral Leishmaniasis

Visceral leishmaniasis (VL; also known as kala-azar), caused by the protozoan parasite Leishmania donovani, is characterized by the inability of the host to generate an effective immune response. The manifestations of the disease depend on the involvement of various immune components such as activation of macrophages, cell mediated immunity, secretion of cytokines and chemokines, etc. Macrophages are the final host cells for Leishmania parasites to multiply, and they are the key to a controlled or aggravated response that leads to clinical symptoms. The two most common macrophage phenotypes are M1 and M2. The pro-inflammatory microenvironment (mainly by IL-1β, IL-6, IL-12, IL-23, and TNF-α cytokines) and tissue injury driven by classically activated macrophages (M1-like) and wound healing driven by alternatively activated macrophages (M2-like) in an anti-inflammatory environment (mainly by IL-10, TGF-β, chemokine ligand (CCL)1, CCL2, CCL17, CCL18, and CCL22). Moreover, on polarized Th cells, chemokine receptors are expressed differently. Typically, CXCR3 and CCR5 are preferentially expressed on polarized Th1 cells, whereas CCR3, CCR4, and CCR8 have been associated with the Th2 phenotype. Further, the ability of the host to produce a cell-mediated immune response capable of regulating and/or eliminating the parasite is critical in the fight against the disease. Here, we review the interactions between parasites and chemokines and chemokine receptors in the pathogenesis of VL.

Assessment of liver function test and associated factors among visceral leishmaniasis patients attending university of gondar leishmaniasis research and treatment center, Northwest Ethiopia

BACKGROUND

Visceral leishmaniasis (VL) is one of the major public health burden, mainly distributed throughout tropical and subtropical regions of the world. Among the Sub-Saharan African countries, Ethiopia is the second most affected country with VL. An Alteration of liver function is a typical manifestation of the disease.

OBJECTIVE

The purpose of conducting this study was to assess liver function tests and associated risk factors among VL patients at Leishmaniasis Research and Treatment Center of University of Gondar Comprehensive Specialized Hospital, North West Ethiopia.

METHOD

Hospital based comparative cross-sectional study design was conducted. A total of 102 study participants were involved in this study. Newly diagnosed VL patients who were attended at Leishmaniasis Research and Treatment Center of University of Gondar Comprehensive Specialized Hospital from 21st February 2020 to 30th September 2020 were included under case group category. On the other hand, age-sex matched apparently healthy study subjects were categorized as control group. Written consent was obtained willingness of patients to participate after ethical clearance was obtained from the Institutional Review Board of School of Medicine, University of Gondar. After overnight fasting, 5ml venous blood was drawn from both VL patients and controls to evaluate liver function tests, including AST, ALT, total bilirubin, albumin, and total protein. Thus, senior health professionals (laboratory technologist) investigate the results using Cobas Integra 400 Plus clinical chemistry analyzer. Data was entered into Epi-data version 4.6 and exported to STATA 14 for analysis of liver function tests and associated risk factors.

RESULT

The result of this study showed that significant mean difference was exhibited in aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin, serum albumin, and total protein level among VL patients and controls. It showed that there was a statistically significant elevation in the level of AST, ALT, and total bilirubin among cases as compared to control. The serum AST level was significantly (p<0.001) elevated among cases as compared to controls. Serum ALT was significantly (p<0.001) elevated among cases compared to controls. Additionally, the total serum bilirubin level was significantly increased (P<0.001) among cases as compared to controls. There was a statistically significant (P<0.001) reduction of serum albumin level among VL patients as compared to controls. Similarly, serum total protein was significantly (P<0.001) reduced in VL patients than control groups.

CONCLUSION

There were significantly higher mean levels of serum AST, ALT, and total bilirubin among VL patients as compared to controls. On the other hand, VL patients showed significantly lowered level of albumin and total protein as compared to controls.

Determinants of Innate Immunity in Visceral Leishmaniasis and Their Implication in Vaccine Development

Leishmaniasis is endemic to the tropical and subtropical regions of the world and is transmitted by the bite of an infected sand fly. The multifaceted interactions between Leishmania, the host innate immune cells, and the adaptive immunity determine the severity of pathogenesis and disease development. Leishmania parasites establish a chronic infection by subversion and attenuation of the microbicidal functions of phagocytic innate immune cells such as neutrophils, macrophages and dendritic cells (DCs). Other innate cells such as inflammatory monocytes, mast cells and NK cells, also contribute to resistance and/or susceptibility to Leishmania infection. In addition to the cytokine/chemokine signals from the innate immune cells, recent studies identified the subtle shifts in the metabolic pathways of the innate cells that activate distinct immune signal cascades. The nexus between metabolic pathways, epigenetic reprogramming and the immune signaling cascades that drive the divergent innate immune responses, remains to be fully understood in Leishmania pathogenesis. Further, development of safe and efficacious vaccines against Leishmaniasis requires a broader understanding of the early interactions between the parasites and innate immune cells. In this review we focus on the current understanding of the specific role of innate immune cells, the metabolomic and epigenetic reprogramming and immune regulation that occurs during visceral leishmaniasis, and the strategies used by the parasite to evade and modulate host immunity. We highlight how such pathways could be exploited in the development of safe and efficacious Leishmania vaccines.

Immunological role of keratinocytes in leishmaniasis

Following inoculation of Leishmania, a protozoan parasite, into the skin of a mammal, the epidermal keratinocytes recognize the parasite and influence the local immune response that can give rise to different outcomes of leishmaniasis. The early keratinocyte-derived cytokines and keratinocytes-T cells interactions shape the anti-leishmanial immune responses that contribute to the resistance or susceptibility to leishmaniasis. The keratinocyte-derived cytokines can directly potentiate the leishmanicidal activity of monocytes and macrophages. As keratinocytes express MHC-II and enhance the expression of costimulatory molecules, these cells act as antigen-presenting cells (APCs) in cutaneous leishmaniasis (CL). Depending on the epidermal microenvironment, the keratinocytes induce various types of effector CD4⁺ T cells. Keratinocyte apoptosis and necrosis have been also implicated in ulceration in CL. Further, keratinocytes contribute to the healing of Leishmania-related cutaneous wounds. However, keratinocyte-derived IL-10 may play a key role in the development of post-kala-azar dermal leishmaniasis (PKDL). In this review, a comprehensive discussion regarding the multiple roles played by keratinocytes during leishmaniasis was provided, while highlighting novel insights concerning the immunological and pathological roles of these cells.

Host immune response against leishmaniasis and parasite persistence strategies: A review and assessment of recent research

Leishmaniasis, a neglected parasitic disease caused by a unicellular protozoan of the genus Leishmania, is transmitted through the bite of a female sandfly. The disease remains a major public health problem and is linked to tropical and subtropical regions, with an endemic picture in several regions, including East Africa, the Mediterranean basin and South America. The different causative species display a diversity of clinical presentations; therefore, the immunological data on leishmaniasis are both scarce and controversial for the different forms and infecting species of the parasite. The present review highlights the main immune parameters associated with leishmaniasis that might contribute to a better understanding of the pathogenicity of the parasite and the clinical outcomes of the disease. Our aim was to provide a concise overview of the immunobiology of the disease and the factors that influence it, as this knowledge may be helpful in developing novel chemotherapeutic and vaccine strategies.