Disulfiram enhances meropenem activity against NDM- and IMP-producing carbapenem-resistant Acinetobacter baumannii infections.

OBJECTIVES: To evaluate the in vitro and in vivo efficacy of the FDA-approved drug disulfiram in combination with meropenem against MBL-expressing carbapenem-resistant Acinetobacter baumannii. METHODS: Chequerboard and antibiotic resistance reversal analysis were performed using 25 clinical isolates producing different MBLs. Three representative strains harbouring NDM, IMP or non-MBL genes were subjected to a time-kill assay to further evaluate this synergistic interaction. Dose-dependent inhibition by disulfiram was assessed to determine IC50 for NDM-1, IMP-7, VIM-2 and KPC-2. Further, to test the efficacy of meropenem monotherapy and meropenem in combination with disulfiram against NDM- and IMP-harbouring A. baumannii, an experimental model of systemic infection and pneumonia was developed using BALB/c female mice. RESULTS: Chequerboard and antibiotic reversal assay displayed a synergistic interaction against MBL-expressing A. baumannii strains with 4- to 32-fold reduction in MICs of meropenem. In time-kill analysis, meropenem and disulfiram exhibited synergy against NDM- and IMP-producing carbapenem-resistant A. baumannii (CRAb) isolates. In vitro dose-dependent inhibition analysis showed that disulfiram inhibits NDM-1 and IMP-7 with IC50 values of 1.5 ± 0.6 and 16.25 ± 1.6 µM, respectively, with slight or no inhibition of VIM-2 (<20%) and KPC-2. The combination performed better in the clearance of bacterial load from the liver and spleen of mice infected with IMP-expressing CRAb. In the pneumonia model, the combination significantly decreased the bacterial burden of NDM producers compared with monotherapy. CONCLUSIONS: These results strongly suggest that the combination of disulfiram and meropenem represents an effective treatment option for NDM- and IMP-associated CRAb infections.

Cadherin profiling for therapeutic interventions in Epithelial Mesenchymal Transition (EMT) and tumorigenesis.

The major hallmarks of Epithelial-Mesenchymal Transition (EMT) is the loss of epithelial cell polarity and loss of expression of the cell- cell adhesion molecule like E-cadherin and acquired mesenchymal cells marker called N-Cadherin. This phenotypical changes of E-M plasticity of cells is extensively considered to be a crucial factor for tumor cells invasion and cancer metastasis; landmark events for transforming a locally growing tumor (benign tumor) into a systemic and live-threatening disease (malignant tumor). Cadherin molecules are adherens junction proteins and expressed as multiple isoforms. Cadherin switching occurs during normal tissue developmental processes; also recapitulates the increasing aggressive behavior and metastatic nature of cancer cells when E-Cadherin converts to N-Cadherin, in particular. There are several mechanisms established that cadherin switching and some of the underlying pathways involves multiple steps associated with migration and invasion of cancer cells, and finally colonization of micro metastatic lesions to form macro-metastasis. Inhibition of metastasis is complicated by the plasticity of cancer cells behaviors and the evolving nature of microenvironment. Although there is no clear evidence how that dynamic structural switching of cadherin family member occurs, stabilized and eventually influence cell behavior, phenotypic transformations and initiate tumorigenesis. Therefore, we emphasize here the major functions of over 20 existing human cadherins in tissue integrity and stability as well as mechanistic understanding on recent work of cadherin ectodomain-mediated adhesion, functional studies of the cell-cell adhesion through key signaling intermediates interacting with other binding partners. We hope understanding on how the dynamic all existing cadherins influence the cell behavior can be targeted to design possible therapeutic interventions to combat its activity and prevent tumor cell growth, invasion and metastasis.

Understanding the role of structural integrity and differential expression of integrin profiling to identify potential therapeutic targets in breast cancer.

Breast cancer is found to be the most prevalent neoplasm in women worldwide. Despite the function of physically tethering cells to the matrix, transmembrane protein integrins are crucially involved in diverse cellular functions such as cell differentiation, proliferation, invasion, migration, and metastasis. Dysregulation of integrins and their interactions with the cells and their microenvironment can trigger several signaling cues that determine the cell fate decision. In this review, we spotlight all pre-existing integrin molecules, their structure, molecular interactions motifs, and function through several cross talks with kinase receptors. We also discuss the role of these integrins as potential prognostic and therapeutic targets and also in the regulation of breast cancer cells differentiation. Understanding of integrin structure and their motifs for ligand interactions in this context will enable the development of new therapeutic approaches to sensitize the tumors and their microenvironment to conventional therapy and overall suppress their metastatic phenotype.

Primary and Immortalized Cultures of Human Proximal Tubule Cells Possess Both Progenitor and Non-Progenitor Cells That Can Impact Experimental Results.

Studies have reported the presence of renal proximal tubule specific progenitor cells which co-express PROM1 and CD24 markers on the cell surface. The RPTEC/TERT cell line is a telomerase-immortalized proximal tubule cell line that expresses two populations of cells, one co-expressing PROM1 and CD24 and another expressing only CD24, identical to primary cultures of human proximal tubule cells (HPT). The RPTEC/TERT cell line was used by the authors to generate two new cell lines, HRTPT co-expressing PROM1 and CD24 and HREC24T expressing only CD24. The HRTPT cell line has been shown to express properties expected of renal progenitor cells while HREC24T expresses none of these properties. The HPT cells were used in a previous study to determine the effects of elevated glucose concentrations on global gene expression. This study showed the alteration of expression of lysosomal and mTOR associated genes. In the present study, this gene set was used to determine if pure populations of cells expressing both PROM1 and CD24 had different patterns of expression than those expressing only CD24 when exposed to elevated glucose concentrations. In addition, experiments were performed to determine whether cross-talk might occur between the two cell lines based on their expression of PROM1 and CD24. It was shown that the expression of the mTOR and lysosomal genes was altered in expression between the HRTPT and HREC24T cell lines based on their PROM1 and CD24 expression. Using metallothionein (MT) expression as a marker demonstrated that both cell lines produced condition media that could alter the expression of the MT genes. It was also determined that PROM1 and CD24 co-expression was limited in renal cell carcinoma (RCC) cell lines.

Hypertension: Constraining the Expression of ACE-II by Adopting Optimal Macronutrients Diet Predicted via Support Vector Machine.

The recent elevation of cases infected from novel COVID-19 has placed the human life in trepidation mode, especially for those suffering from comorbidities. Most of the studies in the last few months have undeniably raised concerns for hypertensive patients that face greater risk of fatality from COVID-19. Furthermore, one of the recent WHO reports has estimated a total of 1.13 billion people are at a risk of hypertension of which two-thirds live in low and middle income countries. The gradual escalation of the hypertension problem andthe sudden rise of COVID-19 cases have placed an increasingly higher number of human lives at risk in low and middle income countries. To lower the risk of hypertension, most physicians recommend drugs that have angiotensin-converting enzyme (ACE) inhibitors. However, prolonged use of such drugs is not recommended due to metabolic risks and the increase in the expression of ACE-II which could facilitate COVID-19 infection. In contrast, the intake of optimal macronutrients is one of the possible alternatives to naturally control hypertension. In the present study, a nontrivial feature selection and machine learning algorithm is adopted to intelligently predict the food-derived antihypertensive peptide. The proposed idea of the paper lies in reducing the computational power while retaining the performance of the support vector machine (SVM) by estimating the dominant pattern in the features space through feature filtering. The proposed feature filtering algorithm has reported a trade-off performance by reducing the chances of Type I error, which is desirable when recommending a dietary food to patients suffering from hypertension. The maximum achievable accuracy of the best performing SVM models through feature selection are 86.17% and 85.61%, respectively.

Protein interactions with metallothionein-3 promote vectorial active transport in human proximal tubular cells.

Metallothionein 3 (MT-3) is a small, cysteine-rich protein that binds to essential metals required for homeostasis, as well as to heavy metals that have the potential to exert toxic effects on cells. MT-3 is expressed by epithelial cells of the human kidney, including the cells of the proximal tubule. Our laboratory has previously shown that mortal cultures of human proximal tubular (HPT) cells express MT-3 and form domes in the cell monolayer, a morphological feature indicative of vectorial active transport, an essential function of the proximal tubule. However, an immortalized proximal tubular cell line HK-2 lacks the expression of MT-3 and fails to form domes in the monolayer. Transfection of HK-2 cells with the MT-3 gene restores dome formation in these cells suggesting that MT-3 is required for vectorial active transport. In order to determine how MT-3 imparts this essential feature to the proximal tubule, we sought to identify proteins that interact either directly or indirectly with MT-3. Using a combination of pulldowns, co-immunoprecipitations, and mass spectrometry analysis, putative protein interactants were identified and subsequently confirmed by Western analysis and confocal microscopy, following which proteins with direct physical interactions were investigated through molecular docking. Our data shows that MT-3 interacts with myosin-9, aldolase A, enolase 1, ß-actin, and tropomyosin 3 and that these interactions are maximized at the periphery of the apical membrane of doming proximal tubule cells. Together these observations reveal that MT-3 interacts with proteins involved in cytoskeletal organization and energy metabolism, and these interactions at the apical membrane support vectorial active transport and cell differentiation in proximal tubule cultures.

Understanding structure-based dynamic interactions of antihypertensive peptides extracted from food sources.

Functional foods are emerging as essential healthy nutritional component due to their abundant wellbeing benefits. Especially the food-derived peptides are considered as key components for playing their biologically active roles. One such robust therapeutics that already exploited with food peptides that help treating high blood pressure via targeting Angiotensin-Converting Enzyme (ACE). This in silico study demonstrated the inhibitory potential of antihypertensive peptides derived from food sources. This study involves an intensive structure-based analysis of enzyme-peptide interactions using Molecular Dynamics (MD) simulations. Interestingly, this study will help us to get deeper understanding on how food peptides achieve successful inhibition of ACE. In this study, the peptide-enzyme complexes revealed two binding pockets, A and B, on either side of the active site Zn atom. Pocket B has a smaller binding site volume than pocket A, comprised of ß-sheets and the active site opening cleft. The interface of the binding sites showed that the enzyme structure was negative to neutral charge, and the peptide structure was positive to neutral charge. The dynamics of complex structures of seven highly potential peptides were performed for 20 ns each at 300 K. Comparative analysis of RMSD, RMSF and binding energies show the enzyme-peptide complexes and the overall stability of apo-enzyme. Importantly, two peptides AFKAWAVAR and IWHHTF showed the highest variation in their RMSD as compared to the apo-enzyme. This study will further be useful for the assessment of the characteristics to predict novel inhibitory peptides that can be generated from food proteins.Communicated by Ramaswamy H. Sarma.

Anti-hypertensive Peptide Predictor: A Machine Learning-Empowered Web Server for Prediction of Food-Derived Peptides with Potential Angiotensin-Converting Enzyme-I Inhibitory Activity.

Angiotensin converting enzyme-I (ACE-I) is a key therapeutic target of the renin-angiotensin-aldosterone system (RAAS), the central pathway of blood pressure regulation. Food-derived peptides with ACE-I inhibitory activities are receiving significant research attention. However, identification of ACE-I inhibitory peptides from different food proteins is a labor-intensive, lengthy, and expensive process. For successful identification of potential ACE-I inhibitory peptides from food sources, a machine learning and structural bioinformatics-based web server has been developed and reported in this study. The web server can take input in the FASTA format or through UniProt ID to perform the in silico gastrointestinal digestion and then screen the resulting peptides for ACE-I inhibitory activity. This unique platform provides elaborated structural and functional features of the active peptides and their interaction with ACE-I. Thus, it can potentially enhance the efficacy and reduce the time and cost in identifying and characterizing novel ACE-I inhibitory peptides from food proteins. URL: http://hazralab.iitr.ac.in/ahpp/index.php.