Epithelial homelessness: an atypical form of anoikis triggered by Leishmania interaction with epithelial cells.

Aim: Leishmaniasis is characterized by a spectrum of diseases with two main clinical forms, cutaneous and visceral, caused by Leishmania tropica and Leishmania donovani, respectively. Studying Leishmania's interaction with the epithelial barrier at the initial site of a bite is crucial to understanding the establishment of the disease. Materials & methods: To discern parasite-host epithelial interaction, we developed in vitro cellular models involving co-cultures of Leishmania and MDCK epithelial cells. Results: Both L. donovani-MDCK and L. tropica-MDCK co-culture models demonstrated a phenomenon known as atypical anoikis apoptosis, typically identified by distinctive 'flipping in' of cell membranes and disordered cytoskeletal frameworks. Conclusion: This study bridges the gap in the fundamental understanding of the intricate latticework involving vector-Leishmania-host and may inform drug development strategies.

Small parasites called Leishmania are passed to humans through the bites of sandflies. These parasites cause three deadly forms of disease: one that affects the organs, one that causes skin lesions and one that affects organ linings. This study looked at how Leishmania parasites behave when they enter through the skin. We found that when the parasites were in contact with cells, the cells changed their shape and lost contact with neighboring cells. This led to a type of cell death known as anoikis, a Greek term meaning 'homelessness'.

Screening of traditional medicinal plant extracts and compounds identifies a potent anti-leishmanial diarylheptanoid from Siphonochilus aethiopicus.

Available anti-leishmanial drugs are associated with toxic side effects, necessitating the search for safe and effective alternatives. This study is focused on identifying traditional medicinal plant natural products for anti-leishmanial potential and possible mechanism of action. Compounds S and T. cordifolia residual fraction (TC-5) presented the best anti-leishmanial activity (IC50: 0.446 and 1.028 mg/ml) against promastigotes at 48 h and less cytotoxicity to THP-1 macrophages. These test agents elicited increased expression of pro-inflammatory cytokines; TNFα and IL-12. In infected untreated macrophages, NO release was suppressed but was significantly (p < 0.05) increased in infected cells treated with compound S. Importantly, Compound S was found to interact with LdTopoIIdimer in silico, resulting in a likely reduced ability of nucleic acid (dsDNA)-remodelling and, as a result, parasite proliferation in vitro. Thereby, Compound S possesses anti-leishmanial activity and this effect occurs via a Th1-mediated pro-inflammatory response. An increase in NO release and its inhibitory effect on LdTopoII may also contribute to the anti-leishmanial effect of compound S. These results show the potential of this compound as a potential starting point for the discovery of novel anti-leishmanial leads.Communicated by Ramaswamy H. Sarma.

tREPs-A New Class of Functional tRNA-Encoded Peptides.

We asked if transfer RNA (tRNA) ever got an opportunity of translating its own sequence during evolution, what would have been the function of such tRNA-encoded peptides (tREPs)? If not, could one artificially synthesize tREPs to study the corresponding functional outcomes? Here, we report a novel, first-in-the-class, chemically synthesized tREP-18 molecule originating from the Escherichia coli tRNA sequence showing potent antileishmanial property. As a first step, E. coli tRNAs were computationally translated into peptide sequence equivalents and a database of full-length hypothetical tREPs was created. The tREP sequences were sent into sequence, structure, and energy filters to narrow down potential peptides for experimental validation. Based on the functional predictions, tREPs were screened against antiparasitic targets, leading to the identification of tREP-18 as a potential antiparasitic peptide. The in vitro assay of chemically synthesized tREP-18 on the Ag83 strain of Leishmania donovani showed its potent antileishmanial property (IC50 value of 22.13 nM). The atomic force microscopy and scanning electron microscopy images indicated significant alteration in the cytoskeletal architecture of tREP-18-treated parasites. Also, tREP-18 seems to destabilize the mitochondrial membrane potential of parasites, disrupting their cellular integrity and leading to parasitic death. The cellular assays of the tREP-18 peptide on the BS12 strain, a clinical isolate of post-kala azar dermal leishmaniasis, demonstrated its significant efficacy at an IC50 value of 15 nM. The tREP-18 peptide showed a toxic effect on the amastigote stage of the parasite, showing macrophage pathogen clearance at a concentration of 22.5 nM. This study provides the proof of the concept of making a new class of functional peptides from tRNA sequences. It also opens a huge untapped tRNA-peptide space toward novel discoveries and applications. In the future, it would be interesting to perform tREP edits and redesign tREPs toward specific applications.

Metalloprotease Gp63-Targeting Novel Glycoside Exhibits Potential Antileishmanial Activity.

Visceral leishmaniasis (VL) and post kala-azar dermal leishmaniasis (PKDL) affect most of the poor populations worldwide. The current treatment modalities include liposomal formulation or deoxycholate salt of amphotericin B, which has been associated with various complications and severe side effects. Encouraged from the recent marked antimalarial effects from plant-derived glycosides, in this study, we have exploited a green chemistry-based approach to chemically synthesize a library of diverse glycoside derivatives (Gly1-12) and evaluated their inhibitory efficacy against the AG83 strain of Leishmania donovani. Among the synthesized glycosides, the in vitro inhibitory activity of Glycoside-2 (Gly2) (1.13 µM IC50 value) on L. donovani promastigote demonstrated maximum cytotoxicity with ~94% promastigote death as compared to amphotericin B that was taken as a positive control. The antiproliferative effect of Gly2 on promastigote encouraged us to analyze the structure-activity relationship of Gly2 with Gp63, a zinc metalloprotease that majorly localizes at the surface of the promastigote and has a role in its development and multiplication. The result demonstrated the exceptional binding affinity of Gly2 toward the catalytic domain of Gp63. These data were thereafter validated through cellular thermal shift assay in a physiologically relevant cellular environment. Mechanistically, reduced multiplication of promastigotes on treatment with Gly2 induces the destabilization of redox homeostasis in promastigotes by enhancing reactive oxygen species (ROS), coupled with depolarization of the mitochondrial membrane. Additionally, Gly2 displayed strong lethal effects on infectivity and multiplication of amastigote inside the macrophage in the amastigote-macrophage infection model in vitro as compared to amphotericin B treatment. Gp63 is also known to bestow protection against complement-mediated lysis of parasites. Interestingly, Gly2 treatment enhances the complement-mediated lysis of L. donovani promastigotes in serum physiological conditions. In addition, Gly2 was found to be equally effective against the clinical promastigote forms of PKDL strain (IC50 value of 1.97 µM); hence, it could target both VL and PKDL simultaneously. Taken together, this study reports the serendipitous discovery of Gly2 with potent antileishmanial activity and proves to be a novel chemotherapeutic prototype against VL and PKDL.

Isolation and identification of carotenoid-producing yeast and evaluation of antimalarial activity of the extracted carotenoid(s) against P. falciparum.

Plasmodial resistance to a variety of plant-based antimalarial drugs has led toward the discovery of more effective antimalarial compounds having chemical or biological origin. Since natural compounds are considered as safer drugs, in this study, yeast strains were identified and compared for the production of carotenoids that are well-known antioxidants and this metabolite was tested for its antiparasitic activity. Plasmodium falciparum 3D7 strain was selected as the target parasite for evaluation of antimalarial activity of yeast carotenoids using in vitro studies. Data were analyzed by FACS (fluorescence-activated cell sorter) and counted via gold standard Giemsa-stained smears. The extracted yeast carotenoids showed a profound inhibitory effect at a concentration of 10-3 µg/µl and 10-4 µg/µl when compared to ß- carotene as control. SYBR Green1 fluorescent dye was used to confirm the decrease in parasitaemia at given range of concentration. Egress assay results suggested that treated parasite remained stalled at schizont stage with constricted morphology and were darkly stained. Non-toxicity of carotenoids on erythrocytes and on human liver hepatocellular carcinoma cells (HepG2 cells) was shown at a given concentration. This report provides strong evidence for antimalarial effects of extracted yeast carotenoids, which can be produced via a sustainable and cost-effective strategy and may be scaled up for industrial application.

Effect of age, comorbidity and remission status on outcome of COVID-19 in patients with hematological malignancies.

BACKGROUND: There is scarcity of data on outcome of COVID-19 in patients with hematological malignancies. Primary objective of study was to analyse the 14-day and 28-day mortality. Secondary objectives were to correlate age, comorbidities and remission status with outcome. METHODS: Retrospective multicentre observational study conducted in 11 centres across India. Total 130 patients with hematological malignancies and COVID-19 were enrolled. RESULTS: Fever and cough were commonest presentation. Eleven percent patients were incidentally detected. Median age of our cohort was 49.5 years. Most of our patients had a lymphoid malignancy (n = 91). One-half patients (52%) had mild infection, while moderate and severe infections contributed to one-fourth each. Sixty seven patients (52%) needed oxygen For treatment of COVID-19 infection, half(n = 66) received antivirals. Median time to RT-PCR COVID-19 negativity was 17 days (7-49 days). Nearly three-fourth (n = 95) of our patients were on anticancer treatment at time of infection, of which nearly two-third (n = 59;64%) had a delay in chemotherapy. Overall, 20% (n = 26) patients succumbed. 14-day survival and 28-day survival for whole cohort was 85.4% and 80%, respectively. One patient succumbed outside the study period on day 39. Importantly, death rate at 1 month was 50% and 60% in relapse/refractory and severe disease cohorts, respectively. Elderly patients(age ≥ 60) (p = 0.009), and severe COVID-19 infection (p = 0.000) had a poor 14-day survival. The 28-day survival was significantly better for patients in remission (p = 0.04), non-severe infection (p = 0.00), and age < 60 years (p = 0.05). CONCLUSIONS: Elderly patients with hematological malignancy and severe covid-19 have worst outcomes specially when disease is not in remission.

Enhanced antibacterial properties and the cellular response of stainless steel through friction stir processing.

Biofilm related bacterial infection is one of the primary causes of implant failure. Limiting bacterial adhesion and colonization of pathogenic bacteria is a challenging task in health care. Here, a highly simplistic processing technique for imparting antibacterial properties on a biomedical grade stainless steel is demonstrated. Low-temperature high strain-rate deformation achieved using submerged friction stir processing resulted in a nearly single phase ultra-fine grain structure. The processed stainless steel demonstrated improved antibacterial properties for both Gram-positive and Gram-negative bacteria, significantly impeding biofilm formation during the in vitro study. Also, the processed stainless steel showed better compatibility with human fibroblasts manifested through apparent cell spreading and proliferation. The substantial antibacterial properties of the processed steel are explained in terms of the favorable electronic characteristics of the metal-oxide and by using classical Derjaguin-Landau-Verwey-Overbeek (DLVO) and the extended DLVO (XDLVO) approach at the cell-substrate interface.

Amyloidosis: The Newer Discovered ALECT2 Associated with der7q add(7).

Amyloidosis is characterized by pathological deposition of abnormal protein aggregates in various tissues, AL protein being the commonest. ALECT 2 is the newest protein described, having a predisposition to affect the kidneys, sometimes the liver and rarely other organs. We present a case of renal amyloid ALECT 2 due to leucocyte cell derived chemotaxin 2, a novel amyloidogenic protein. The patient presented with mild proteinuria, scattered plasma cells on bone marrow examination and altered kappa/lambda ratio with associated cytogenetic abnormality of der7q add(7). It is essential to correctly type this protein and differentiate it from AL during diagnosis for appropriate and effective clinical management.

Primary choriocarcinoma of appendix mimicking acute appendicitis.

Choriocarcinoma is a malignant trophoblastic cancer, the incidence of primary choriocarcinoma (PCC) of the gastrointestinal tract (GIT) being extremely rare, with only 14 cases being reported in worldwide literature. Here we present an extremely rare case of PCCof the appendix in a 32-year-old male who presented with acute pain abdomen. Histopathological examination revealed PCC of the appendix. Examination of the testis was unremarkable. Further investigations revealed a very high serum beta-human chorionic gonadotropin (b-HCG) titer with a normal carcinoembryonic antigen (CEA). Radiological imaging showed multiple areas of liver metastasis. Chemotherapy-based treatment with bleomycin, etoposide, and cisplatin (BEP) regime was advised, however the patient failed to follow-up for further management.

Hepatobiliary fascioliasis in non-endemic zones: a surprise diagnosis.

Fascioliasis is a zoonotic infection caused by Fasciola hepatica. Because of population migration and international food trade, human fascioliasis is being an increasingly recognised entity in nonendemic zones. In most parts of Asia, hepatobiliary fascioliasis is sporadic. Human hepatobiliary infection by this trematode has two distinct phases: an acute hepatic phase and a chronic biliary phase. Hepatobiliary infection is mostly associated with intense peripheral eosinophilia. In addition to classically defined hepatic phase and biliary phase fascioliasis, some cases may have an overlap of these two phases. Chronic liver abscess formation is a rare presentation. We describe a surprise case of hepatobiliary fascioliasis who presented to us with liver abscess without intense peripheral eosinophilia, a rare presentation of human fascioliasis especially in non-endemic zones.