Plasmodium falciparum heat shock proteins as antimalarial drug targets: An update.

Global efforts to eradicate malaria are threatened by multiple factors, particularly the emergence of antimalarial drug resistant strains of Plasmodium falciparum. Heat shock proteins (HSPs), particularly P. falciparum HSPs (PfHSPs), represent promising drug targets due to their essential roles in parasite survival and virulence across the various life cycle stages. Despite structural similarities between human and malarial HSPs posing challenges, there is substantial evidence for subtle differences that could be exploited for selective drug targeting. This review provides an update on the potential of targeting various PfHSP families (particularly PfHSP40, PfHSP70, and PfHSP90) and their interactions within PfHSP complexes as a strategy to develop new antimalarial drugs. In addition, the need for a deeper understanding of the role of HSP complexes at the host-parasite interface is highlighted, especially heterologous partnerships between human and malarial HSPs, as this opens novel opportunities for targeting protein-protein interactions crucial for malaria parasite survival and pathogenesis.

In silico identification of modulators of J domain protein-Hsp70 interactions in Plasmodium falciparum: a drug repurposing strategy against malaria.

Plasmodium falciparum is a unicellular, intracellular protozoan parasite, and the causative agent of malaria in humans, a deadly vector borne infectious disease. A key phase of malaria pathology, is the invasion of human erythrocytes, resulting in drastic remodeling by exported parasite proteins, including molecular chaperones and co-chaperones. The survival of the parasite within the human host is mediated by P. falciparum heat shock protein 70s (PfHsp70s) and J domain proteins (PfJDPs), functioning as chaperones-co-chaperones partnerships. Two complexes have been shown to be important for survival and pathology of the malaria parasite: PfHsp70-x-PFE0055c (exported); and PfHsp70-2-PfSec63 (endoplasmic reticulum). Virtual screening was conducted on the drug repurposing library, the Pandemic Response Box, to identify small-molecules that could specifically disrupt these chaperone complexes. Five top ranked compounds possessing preferential binding affinity for the malarial chaperone system compared to the human system, were identified; three top PfHsp70-PfJDP binders, MBX 1641, zoliflodacin and itraconazole; and two top J domain binders, ezetimibe and a benzo-diazepinone. These compounds were validated by repeat molecular dockings and molecular dynamics simulation, resulting in all the compounds, except for MBX 1461, being confirmed to bind preferentially to the malarial chaperone system. A detailed contact analysis of the PfHsp70-PfJDP binders identified two different types of modulators, those that potentially inhibit complex formation (MBX 1461), and those that potentially stabilize the complex (zoliflodacin and itraconazole). These data suggested that zoliflodacin and itraconazole are potential novel modulators specific to the malarial system. A detailed contact analysis of the J domain binders (ezetimibe and the benzo-diazepinone), revealed that they bound with not only greater affinity but also a better pose to the malarial J domain compared to that of the human system. These data suggested that ezetimibe and the benzo-diazepinone are potential specific inhibitors of the malarial chaperone system. Both itraconazole and ezetimibe are FDA-approved drugs, possess anti-malarial activity and have recently been repurposed for the treatment of cancer. This is the first time that such drug-like compounds have been identified as potential modulators of PfHsp70-PfJDP complexes, and they represent novel candidates for validation and development into anti-malarial drugs.

Survey on Sensors and Smart Devices for IoT Enabled Intelligent Healthcare System.

The Internet of Things (IoT) in the healthcare system is rapidly changing from the conventional hospital and concentrated specialist behavior to a distributed, patient-centric approach. With the advancement of new techniques, a patient needs sophisticated healthcare requirements. IoT-enabled intelligent health monitoring system with sensors and devices is a patient analysis technique to monitor the patient 24 h a day. IoT is swapping the architecture and has improved the application of different complex systems. Healthcare devices are one of the most remarkable applications of the IoT. Many patient monitoring techniques are available in the IoT platform. This review presents an IoT-enabled intelligent health monitoring system by analyzing the papers reported between 2016 and 2023. This survey also discusses the concept of big data in IoT networks and the IoT computing technology known as edge computing. This review concentrated on sensors and smart devices used in intelligent IoT based health monitoring systems with merits and demerits. This survey gives a brief study based on sensors and smart devices used in IoT smart healthcare systems.

Exported J domain proteins of the human malaria parasite.

The heat shock protein 40 (Hsp40) family, also called J domain proteins (JDPs), regulate their Hsp70 partners by ensuring that they are engaging the right substrate at the right time and in the right location within the cell. A number of JDPs can serve as co-chaperone for a particular Hsp70, and so one generally finds many more JDPs than Hsp70s in the cell. In humans there are 13 Hsp70s and 49 JDPs. The human malaria parasite, Plasmodium falciparum, has dedicated an unusually large proportion of its genome to molecular chaperones, with a disproportionately high number of JDPs (PfJDPs) of 49 members. Interestingly, just under half of the PfJDPs are exported into the host cell during the asexual stage of the life cycle, when the malaria parasite invades mature red blood cells. Recent evidence suggests that these PfJDPs may be functionalizing both host and parasite Hsp70s within the infected red blood cell, and thereby driving the renovation of the host cell towards pathological ends. PfJDPs have been found to localize to the host cytosol, mobile structures within the host cytosol (so called "J Dots"), the host plasma membrane, and specialized structures associated with malaria pathology such as the knobs. A number of these exported PfJDPs are essential, and there is growing experimental evidence that they are important for the survival and pathogenesis of the malaria parasite. This review critiques our understanding of the important role these exported PfJDPs play at the host-parasite interface.

Hsp90 and Associated Co-Chaperones of the Malaria Parasite.

Heat shock protein 90 (Hsp90) is one of the major guardians of cellular protein homeostasis, through its specialized molecular chaperone properties. While Hsp90 has been extensively studied in many prokaryotic and higher eukaryotic model organisms, its structural, functional, and biological properties in parasitic protozoans are less well defined. Hsp90 collaborates with a wide range of co-chaperones that fine-tune its protein folding pathway. Co-chaperones play many roles in the regulation of Hsp90, including selective targeting of client proteins, and the modulation of its ATPase activity, conformational changes, and post-translational modifications. Plasmodium falciparum is responsible for the most lethal form of human malaria. The survival of the malaria parasite inside the host and the vector depends on the action of molecular chaperones. The major cytosolic P. falciparum Hsp90 (PfHsp90) is known to play an essential role in the development of the parasite, particularly during the intra-erythrocytic stage in the human host. Although PfHsp90 shares significant sequence and structural similarity with human Hsp90, it has several major structural and functional differences. Furthermore, its co-chaperone network appears to be substantially different to that of the human host, with the potential absence of a key homolog. Indeed, PfHsp90 and its interface with co-chaperones represent potential drug targets for antimalarial drug discovery. In this review, we critically summarize the current understanding of the properties of Hsp90, and the associated co-chaperones of the malaria parasite.

Role of the J Domain Protein Family in the Survival and Pathogenesis of Plasmodium falciparum.

Plasmodium falciparum has dedicated an unusually large proportion of its genome to molecular chaperones (2% of all genes), with the heat shock protein 40 (Hsp40) family (now called J domain proteins, JDPs) exhibiting evolutionary radiation into 49 members. A large number of the P. falciparum JDPs (PfJDPs) are predicted to be exported, with certain members shown experimentally to be present in the erythrocyte cytosol (PFA0660w and PFE0055c) or erythrocyte membrane (ring-infected erythrocyte surface antigen, RESA). PFA0660w and PFE0055c are associated with an exported plasmodial Hsp70 (PfHsp70-x) within novel mobile structures called J-dots, which have been proposed to be dedicated to the trafficking of key membrane proteins such as erythrocyte membrane protein 1 (PfEMP1). Well over half of the PfJDPs appear to be essential, including the J-dot PfJDP, PFE0055c, while others have been found to be required for growth under febrile conditions (e.g. PFA0110w, the ring-infected erythrocyte surface antigen protein [RESA]) or involved in pathogenesis (e.g. PF10_0381 has been shown to be important for protrusions of the infected red blood cell membrane, the so-called knobs). Here we review what is known about those PfJDPs that have been well characterised, and may be directly or indirectly involved in the survival and pathogenesis of the malaria parasite.

Analysis, Modeling, and Representation of COVID-19 Spread: A Case Study on India.

Coronavirus outbreak is one of the challenging pandemics for the entire human population on Earth. Techniques, such as the isolation of infected people and maintaining social distancing, are the only preventive measures against the pandemic. The actual estimation of the number of infected peoples with limited data is an indeterminate problem faced by data scientists. There are several techniques in the existing literature, including reproduction number and case fatality rate, for predicting the duration of a pandemic and infectious population. This article presents a case study of different techniques for analyzing, modeling, and representing the data associated with a pandemic such as COVID-19. We further propose an algorithm for estimating infection transmission states in a particular area. This work also presents an algorithm for estimating end time of a pandemic from the susceptible infectious and recovered model. Finally, this article presents the empirical and data analysis to study the impact of transmission probability, rate of contact, infectious, and susceptible population on the pandemic spread.

Exported plasmodial J domain protein, PFE0055c, and PfHsp70-x form a specific co-chaperone-chaperone partnership.

Plasmodium falciparum is a unicellular protozoan parasite and causative agent of a severe form of malaria in humans, accounting for very high worldwide fatality rates. At the molecular level, survival of the parasite within the human host is mediated by P. falciparum heat shock proteins (PfHsps) that provide protection during febrile episodes. The ATP-dependent chaperone activity of Hsp70 relies on the co-chaperone J domain protein (JDP), with which it forms a chaperone-co-chaperone complex. The exported P. falciparum JDP (PfJDP), PFA0660w, has been shown to stimulate the ATPase activity of the exported chaperone, PfHsp70-x. Furthermore, PFA0660w has been shown to associate with another exported PfJDP, PFE0055c, and PfHsp70-x in J-dots, highly mobile structures found in the infected erythrocyte cytosol. Therefore, the present study aims to conduct a structural and functional characterization of the full-length exported PfJDP, PFE0055c. Recombinant PFE0055c was successfully expressed and purified and found to stimulate the basal ATPase activity of PfHsp70-x to a greater extent than PFA0660w but, like PFA0660w, did not significantly stimulate the basal ATPase activity of human Hsp70. Small-molecule inhibition assays were conducted to determine the effect of known inhibitors of JDPs (chalcone, C86) and Hsp70 (benzothiazole rhodacyanines, JG231 and JG98) on the basal and PFE0055c-stimulated ATPase activity of PfHsp70-x. In this study, JG231 and JG98 were found to inhibit both the basal and PFE0055c-stimulated ATPase activity of PfHsp70-x. C86 only inhibited the PFE0055c-stimulated ATPase activity of PfHsp70-x, consistent with PFE0055c binding to PfHsp70-x through its J domain. This research has provided further insight into the molecular basis of the interaction between these exported plasmodial chaperones, which could inform future antimalarial drug discovery studies.

The peptidyl-prolyl cis-trans isomerase activity of the wheat cyclophilin, TaCypA-1, is essential for inducing thermotolerance in Escherichia coli.

Growth at high temperatures is one of the desired features for industrial applications of microbes, as it results in decrease in contamination and enhanced solubility of certain substrates. In this study, it is demonstrated that heterologous expression of a wheat cyclophilin, TaCypA-1, confers thermotolerance to Escherichia coli. The TaCypA-1 possesses peptidyl-prolyl cis-trans isomerase (PPIase) activity that catalyses cis to trans isomerization of the peptidyl prolyl bonds, a rate limiting step in protein folding. Expression of deleted mutants of TaCypA-1, that lacked PPIase activity, resulted in abrogation of thermotolerance, providing the first evidence that this activity plays a key role in stress tolerance of cells and can be exploited for industrial applications. Further, we also demonstrate that TaCypA-1 interacts with calmodulin (CaM), and the CaM-binding domain is localized to amino acid residues 51-71 in the N-terminus region.

Characterization of Peptidyl-Prolyl Cis-Trans Isomerase- and Calmodulin-Binding Activity of a Cytosolic Arabidopsis thaliana Cyclophilin AtCyp19-3.

Cyclophilins, which bind to immunosuppressant cyclosporin A (CsA), are ubiquitous proteins and constitute a multigene family in higher organisms. Several members of this family are reported to catalyze cis-trans isomerisation of the peptidyl-prolyl bond, which is a rate limiting step in protein folding. The physiological role of these proteins in plants, with few exceptions, is still a matter of speculation. Although Arabidopsis genome is predicted to contain 35 cyclophilin genes, biochemical characterization, imperative for understanding their cellular function(s), has been carried only for few of the members. The present study reports the biochemical characterization of an Arabidopsis cyclophilin, AtCyp19-3, which demonstrated that this protein is enzymatically active and possesses peptidyl-prolyl cis-trans isomerase (PPIase) activity that is specifically inhibited by CsA with an inhibition constant (Ki) of 18.75 nM. The PPIase activity of AtCyp19-3 was also sensitive to Cu(2+), which covalently reacts with the sulfhydryl groups, implying redox regulation. Further, using calmodulin (CaM) gel overlay assays it was demonstrated that in vitro interaction of AtCyp19-3 with CaM is Ca(2+)-dependent, and CaM-binding domain is localized to 35-70 amino acid residues in the N-terminus. Bimolecular fluorescence complementation assays showed that AtCyp19-3 interacts with CaM in vivo also, thus, validating the in vitro observations. However, the PPIase activity of the Arabidopsis cyclophilin was not affected by CaM. The implications of these findings are discussed in the context of Ca(2+) signaling and cyclophilin activity in Arabidopsis.

Molecular characterization of cyclophilin A-like protein from Piriformospora indica for its potential role to abiotic stress tolerance in E. coli.

BACKGROUND: Cyclophilins (CyP), conserved in all genera, are known to have regulatory responses of various cellular processes including stress tolerance. Interestingly, CyP has a crucial role as peptidyl-prolyl cis-trans isomerases (PPIases). Our earlier in silico based approach resulted into the identification of cyclophilin family from rice, Arabidopsis and yeast. In our recent report, we discovered a new OsCYP-25 from rice. Here, we identified a novel cyclophylin A-like protein (PiCyP) from Piriformospora indica which is responsible for abiotic stress tolerance in E. coli. RESULTS: Cyclophylin A-like protein (CyPA) (accession number GQ214003) was selected from cDNA library. The genomic organization CyPA revealed a 1304 bp of CyPA in P. indica genome, showing 10 exons and 9 introns. Further, CyPA was evident in PCR with gDNA and cDNA and Southern blot analysis. The phylogenetic examination of CyPA of P. indica showed that it is closed to human cyclophilin. The uniqueness of PiCyPA protein was apparent in western blot study. Kinetics of purified PiCyPA protein for its PPIas activity was determined via first order rate constant (0.104 s-1) in the presence of 1 µg of PiCyPA, with increasing PiCyPA concentration, in the presence of cyclosporin A (CsA) and the inhibition constant (4.435 nM) of CsA for inhibition of PiCyPA. The differential response of E. coli harbouring pET28a-PiCypA was observed for their different degree of tolerance to different abiotic stresses as compared to empty pET28a vector. CONCLUSIONS: Overexpression of PiCyPA protein E. coli cells confer enhanced tolerance to wide range of abiotic stresses. Thus, this study provides the significance of PiCypA as a molecular chaperone which advanced cellular stress responses of E. coli cells under adverse conditions, and it, furthermore, confirms the mounting the sustainability of E. coli for exploitation in recombinant proteins production. Additionally, the PiCyPA gene cooperates substantial functions in cellular network of stress tolerance mechanism, essentially required for various developmental stages, and might be a potential paramount candidate for crop improvement and its sustainable production under adverse conditions.

Structural and biochemical characterization of the cytosolic wheat cyclophilin TaCypA-1.

Cyclophilins belong to a family of proteins that bind to the immunosuppressive drug cyclosporin A (CsA). Several members of this protein family catalyze the cis-trans isomerization of peptide bonds preceding prolyl residues. The present study describes the biochemical and structural characteristics of a cytosolic cyclophilin (TaCypA-1) cloned from wheat (Triticum aestivum L.). Purified TaCypA-1 expressed in Escherichia coli showed peptidyl-prolyl cis-trans isomerase activity, which was inhibited by CsA with an inhibition constant of 78.3 nM. The specific activity and catalytic efficiency (kcat/Km) of the purified TaCypA-1 were 99.06 ± 0.13 nmol s(-1) mg(-1) and 2.32 × 10(5) M(-1) s(-1), respectively. The structures of apo TaCypA-1 and the TaCypA-1-CsA complex were determined at 1.25 and 1.20 Šresolution, respectively, using X-ray diffraction. Binding of CsA to the active site of TaCypA-1 did not result in any significant conformational change in the apo TaCypA-1 structure. This is consistent with the crystal structure of the human cyclophilin D-CsA complex reported at 0.96 Å resolution. The TaCypA-1 structure revealed the presence of a divergent loop of seven amino acids (48)KSGKPLH(54) which is a characteristic feature of plant cyclophilins. This study is the first to elucidate the structure of an enzymatically active plant cyclophilin which shows peptidyl-prolyl cis-trans isomerase activity and the presence of a divergent loop.

Developmental changes in storage proteins and peptidyl prolyl cis-trans isomerase activity in grains of different wheat cultivars.

In the present study, storage proteins from five different wheat cultivars were extracted, fractionated and evaluated for their accumulation at different stages of development. SDS-PAGE analysis revealed that the accumulation of high molecular weight glutenin subunits was cultivar and stage dependent. However, low molecular weight glutenin subunits' accumulation was not altered significantly after 16days post anthesis in any of the cultivars. The rheological parameters (storage- and loss-modulus) of dough and gluten showed close association with either gliadins or glutenins. Peptidyl prolyl cis-trans isomerase (PPIase) activity, measured at different stages of grains development, showed variability with both the developmental stage and cultivar, and appeared to be primarily due to cyclophilins. Principal component analysis revealed the association of PPIase activity with either gliadin or total proteins, suggesting their significant role in the deposition of storage proteins in wheat.