Hemin competitively inhibits HSPA8 ATPase activity mitigating its foldase function.

Hemolysis in red blood cells followed by hemoglobin degradation results in high hemin levels in the systemic circulation. Such a level of hemin is disastrous for cells and tissues and is considerably responsible for the pathologies of diseases like severe malaria. Hemin's hydrophobic chemical nature and structure allow it to bind several proteins leading to their functional modification. Such modifications in physiologically relevant proteins can have a high impact on various cellular processes. HSPA8 is a chaperone that has a protective role in oxidative stress by aiding protein refolding. Through ATPase activity assays we found that hemin can competitively inhibit ATP hydrolysis by the chaperone HSPA8. Hemin as such does not affect the structural integrity of the protein which is inferred from CD spectroscopy and Gel filtration but it hinders the ATP-dependent foldase function of the chaperone. HSPA8 was not able to cause the refolding of the model protein lysozyme in the presence of hemin. The loss in HSPA8 function was due to competition between hemin and ATP as the chaperone was able to regain the foldase function when the concentration of ATP was gradually increased with hemin present at the inhibitory concentration. In-silico studies to establish the competition for the specific binding site revealed that ATP was unable to replace hemin from the ATP binding pocket of HSPA8 and was forced to form a non-specific and unstable complex. In-vitro isothermal calorimetry revealed that the affinity of ATP for binding to HSPA8 was reduced 22 folds in the presence of hemin. The prevention of HSPA8's cytoprotective function by hemin can be a major factor contributing to the overall cellular damage during hemin accumulation in the case of severe malaria and other hemolytic diseases.

Role Transformation of HSPA8 to Heme-peroxidase After Binding Hemin to Catalyze Heme Polymerization.

Hemin, a byproduct of hemoglobin degradation, inflicts oxidative insult to cells. Following its accumulation, several proteins are recruited for heme detoxification with heme oxygenase playing the key role. Chaperones play a protective role primarily by preventing protein degradation and unfolding. They also are known to have miscellaneous secondary roles during similar situations. To discover a secondary role of chaperones during heme stress we studied the role of the chaperone HSPA8 in the detoxification of hemin. In-silico studies indicated that HSPA8 has a well-defined biophoric environment to bind hemin. Through optical difference spectroscopy, we found that HSPA8 binds hemin through its N-terminal domain with a Kd value of 5.9 ± 0.04 µM and transforms into a hemoprotein. The hemoprotein was tested for exhibiting peroxidase activity using guaiacol as substrate. The complex formed reacts with H2O2 and exhibits classical peroxidase activity with an ability to oxidize aromatic and halide substrates. HSPA8 is dose-dependently catalyzing heme polymerization through its N-terminal domain. The IR results reveal that the polymer formed exhibits structural similarities to ß-hematin suggesting its covalent nature. The polymerization mechanism was tested through optical spectroscopy, spin-trap, and activity inhibition experiments. The results suggest that the polymerization occurs through a peroxidase-H2O2 system involving a one-electron transfer mechanism, and the formation of free radical and radical-radical interaction. It highlights a possible role of the HSPA8-hemin complex in exhibiting cytoprotective function during pathological conditions like malaria, sickle cell disease, etc.

Tandem (4 + 3)-Annulation of Aziridines: Stereoselective Access to Fused Azepinoindoles.

A stereoselective tandem (4 + 3)-coupling of aziridines with 4-alkylidene indole malonates has been disclosed under Cu-catalysis involving a base-promoted annulation. The methodology serves as a potential approach toward the facile construction of fused azepinoindoles with good yields and diastereoselectivities. Late-stage natural product and drug modification as well as preliminary investigations for the enantioselective (4 + 3)-annulation are important practical features.

Plasmodium falciparum FIKK 9.1 kinase modeling to screen and identify potent antimalarial agents from chemical library.

The Plasmodium FIKK kinases are diverged from human kinases structurally. They harbour conserved ATP-binding domains that are non-homologous to other existing kinases. FIKK9.1 kinase is considered as an essential protein for parasite survival. It is localized in major organelles present in parasite and trafficked throughout the infected RBC. It is speculated that FIKK9.1 may phosphorylate several substrates in the parasite's proteome and contribute to parasite survival. Therefore, FIKK9.1 is an attractive target that may lead to a novel class of antimalarials. To identify specific FIKK9.1 kinase inhibitors, we virtually screened organic structural scaffolds from a library of 623 entries. The top hits were identified based on conformations and molecular interactions with the ATP biophore. The hits were also validated under in vitro conditions. In this study, we identified seven top hit organic compounds that may arrest the growth of parasites by inhibiting FIKK9.1 kinase. Evaluation of top hit compounds in antimalarial activity assay identifies that the highly substituted 1,3-selenazolidin-2-imine 1 and thiophene 2 are inhibiting parasite growth with an IC50 of 3.2 ± 0.27 µg/ml and 3.13 ± 0.16 µg/ml, respectively. These functionalized heterocyclic compounds 1 and 2 kills the malaria parasite with an IC50 of 2.68 ± 0.02 µg/ml and 3.08 ± 0.14 µg/ml, respectively. Isothermal titration calorimetry analysis indicate that ATP is binding to the FIKK9.1 kinase. The dissociation constant (Kd) is measured to be 27.8 ± 2.07 µM with a stoichiometry of n = 1. The heterocyclic scaffolds 1 and 2 were abolishing the binding of ATP into the binding pocket. They in-turn reduce the ability of FIKK9.1 kinase to phosphorylate its substrate. Our study found that compounds 1 and 2 are potent inhibitor of FIKK9.1 kinase and the inhibition of FIKK9.1 kinase using small molecules disturbs the parasite life cycle and leads to the death of parasites. This provides new insight in development of novel antimalarials. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03677-x.

Molecular modelling, docking and network analysis of phytochemicals from Haritaki churna: role of protein cross-talks for their action.

Phytochemicals are bioactive agents present in medicinal plants with therapeutic values. Phytochemicals isolated from plants target multiple cellular processes. In the current work, we have used fractionation techniques to identify 13 bioactive polyphenols in ayurvedic medicine Haritaki Churna. Employing the advanced spectroscopic and fractionation, structure of bioactive polyphenols was determined. Blasting the phytochemical structure allow us to identify a total of 469 protein targets from Drug bank and Binding DB. Phytochemicals with their protein targets from Drug bank was used to create a phytochemical-protein network comprising of 394 nodes and 1023 edges. It highlights the extensive cross-talk between protein target corresponding to different phytochemicals. Analysis of protein targets from Binding data bank gives a network comprised of 143 nodes and 275 edges. Taking the data together from Drug bank and binding data, seven most prominent drug targets (HSP90AA1, c-Src kinase, EGFR, Akt1, EGFR, AR, and ESR-α) were found to be target of the phytochemicals. Molecular modelling and docking experiment indicate that phytochemicals are fitting nicely into active site of the target proteins. The binding energy of the phytochemicals were better than the inhibitors of these protein targets. The strength and stability of the protein ligand complexes were further confirmed using molecular dynamic simulation studies. Further, the ADMET profiles of phytochemicals extracted from HCAE suggests that they can be potential drug targets. The phytochemical cross-talk was further proven by choosing c-Src as a model. HCAE down regulated c-Src and its downstream protein targets such as Akt1, cyclin D1 and vimentin. Hence, network analysis followed by molecular docking, molecular dynamics simulation and in-vitro studies clearly highlight the role of protein network and subsequent selection of drug candidate based on network pharmacology.Communicated by Ramaswamy H. Sarma.

Extraction, phytochemical characterization and anti-cancer mechanism of Haritaki churna: An ayurvedic formulation.

Haritaki churna (HC), a single herb ayurvedic formulations is known to be prescribed for various gastro-intestinal disorders in Ayurveda. Haritaki churna aqueous extract (HCAE) has anti-cancer activity against different types of cancer cells with an IC50 in the range of 50-97 µg/ml. Bioavailability of Haritaki Churna is very high in digestive track and treatment of colorectal cancer cells HCT-116, DLD1, HT-29 with HCAE reduces its cellular viability with anti-cancer IC50 70µg/ml. HCAE consumption is safe for human as it didn't affect the cellular viability of primary human PBMCs or non-cancerogenic HEK-293 cells. Haritaki churna was found to be stable in biological gastric fluids and bioactive agents are not losing their anti-cancer activity under such harsh conditions. The HPLC Chromatogram of HCAE is giving 13 major peaks and 11 minor peaks. Exploiting LC-MS, IR and NMR spectroscopic techniques, a total of 13 compounds were identified from HCAE namely Shikimic acid, Chebulic acid, gallic acid, 5-hydroxymethylfurfural, Protocatechuic acid, 4-O-galloyl-shikimic Acid, 5-O-galloyl-shikimic Acid, Methylgallate, corilagin, 1, 2, 6, Tri-O-galloyl ß-D-glucose, chebulagic acid, chebulinic acid, and Ellagic acid. Reconstitution and subtraction of phytochemicals from the mixture indicate that Ellagic acid significantly contribute into anti-cancer effect of HCAE. Cancer cells treated with ellagic acid from HCAE were incapable of completing their cell-cycle and halted the cell-cycle at DNA synthesis S-Phase, as demonstrated by decreased cyclin A2 expression levels with increasing ellagic acid concentration. Halting of cells at S-phase causes induction of apoptosis in cancer cells. Cancer cells exhibiting DNA fragmentation, changes in expression of several apoptotic proteins such as Bcl2, cytochrome-c and formation of cleaved products of caspase 3 and PARP-1 suggests ellagic acid induces cell death via mitochondrial pathway of apoptosis.

Isolation and characterization of Newcastle disease virus from biological fluids using column chromatography.

Newcastle disease virus (NDV), belonging to the species avian orthoavulavirus 1, genus Orthoavulavirus, and family Paramyxoviridae, is responsible for Newcastle disease in poultry and other avian species. It has shown significant potential as an oncolytic virus and as a vector for vaccine delivery. NDV from infected biological serum is usually isolated or purified using density gradient ultracentrifugation. However, it has many disadvantages, including the fact that it is time consuming and can process only a limited quantity of sample at one time. In our study, native agarose gel electrophoresis and dynamic light scattering (DLS) analysis showed that NDV carried a net negative surface charge. Thus, we purified the virus using a HiTrap Q Sepharose Fast Flow anion exchange column with salt elution. Hemagglutination assay and plaque assay showed that the procedure yielded high-purity NDV particles with a recovery of more than 80%, and the process was fast and simple. The purity of the virus was confirmed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blot analysis. The hydrodynamic volume and 'dry state' diameter of the purified NDV were analyzed using dynamic light scattering and transmission electron microscopy and were to be in the range of 200-300 nm. The viruses did not exhibit any deviation from their known physical properties. The genome of the virus was also detected by amplifying a 423-bp region using reverse transcription-polymerase chain reaction. Our study confirmed that NDV could be effectively purified using an anion exchange column. In addition, the procedure could be easily upscaled or downscaled based on the experimental requirements.

Delivery of Small Molecules by Syndiotactic Peptides for Breast Cancer Therapy.

The utilization of peptide-based drug delivery systems has been suboptimal due to their poor proteolytic susceptibility, poor cell permeability, and limited tumor homing capabilities. Earlier attempts in using d-enantiomers in peptide sequences increased proteolytic stability but have compromised the overall penetration capability. We designed a series of peptides (STRAPs) with a syndiotactic polypeptide backbone that can potentially form a spatial array of cationic groups, an important feature that facilitates cellular uptake. The peptides penetrate cell membranes through a combination of active and passive modes. Furthermore, the cellular uptake of the peptides was unaffected by the presence of or treatment with bovine serum and human plasma. The designed peptides successfully delivered methotrexate, an anticancer drug, to the in vitro and in vivo models of breast cancer, with the best performing peptide STRAP-4-MTX conjugate having an EC50 value of 1.34 µM. Peptide drug delivery in mouse xenograft models showed a greater reduction of primary tumor and metastasis of breast cancer, in comparison to methotrexate of the same dose. The in vivo biodistribution assay of the STRAP-4 peptide suggests that the peptide accumulates at the tumor site after 2 h of treatment, and in the absence of tumors, the peptide gets metabolized and excreted from the system.

Hemin acts as CD36 ligand to activate down-stream signalling to disturb immune responses and cytokine secretion from macrophages.

Inflammatory responses to hemin are believed to play an important role in tissue damage and cerebral malaria pathology. Macrophage exposed to hemin exhibits modulation of non-opsonic phagocytosis of aged RBCs, ability to kill bacteria and secretion of cytokines. Immuno-fluorescence study indicates translocation and sequestration of CD36 within the intracellular storage in the hemin treated macrophages. It in-turn modulates the global cytokine secretion from macrophages. CD36 has strong affinity for hemin with a dissociation constant of 1.26±0.24 µM. CD36 has hemin bio-phoric environment involving R292, D372 and Q382. The mutation in biophoric residues significantly reduced the affinity towards hemin. Hemin stimulated MG63 cells (transfected with CD36) showed several folds increment in cytokines TNFα, MCP-1, RANTES and CCL1 and CD36-hemin interaction is crucial for aberrant cytokine secretion. CD-36: Hemin interaction is driving down-stream signalling and subsequent recruitment of adaptor proteins to the cytosolic domain of CD36. Immunoprecipitation of membrane bound CD36 gives Lyn kinase as potential adaptor protein down-stream to CD36: hemin signalling. Interestingly, disruption of Lyn kinase abolishes the hemin mediated dysregulation of immune responses. In summary, hemin-CD36-Lyn kinase signalling axis could be a contribution factor to severe malaria pathology and prognosis.

CD36 Ectodomain Detects Apoptosis in Mammalian Cells.

The cells that undergo apoptosis show phosphatidylserine (PS) on the cell membrane. The fluorescently labeled hCD36_ecto is staining and detecting apoptotic cells in a flow-based assay with several advantages over Annexin V. The human CD36 ectodomain (hCD36_ecto) is stable for a range of temperatures and experimental conditions and doesn't require Ca2+ for detecting apoptosis and specific towards PS compared to other lipids. The blocking with unlabeled hCD36_ecto reduces the staining of Annexin V-FITC for apoptotic cells, whereas R63A does not affect the binding of Annexin V- FITC to apoptotic cells. It indicates the role of CD36-PS interaction in detecting apoptotic cells. Dual-staining with hCD36_ecto-FITC/PI is universally detecting apoptosis in different nucleated cells or eryptosis in non-nucleated RBCs. Hence, our study highlights the utility of CD36 as a probe to detect apoptosis in mammalian cells. It might be a robust, economical reagent for the scientific community to facilitate their research.

Hemozoin is a potential threat in cerebral malaria pathology through the induction of RBC-EC cytoadherence.

Cerebral malaria is an outcome of multifaceted and complicated condition. Cytoadherence is one critical factor in cerebral malaria pathology as high order cytoadherence complexes result in vascular congestion and cell apoptosis. Morphological abnormalities in uninfected RBCs can be a contributing factor to aggravate cytoadherence. Malaria pigment hemozoin is a potential bioactive molecule and the role of this pigment in cerebral malaria pathology is not completely understood. To understand this, primarily we investigated the impact of hemozoin pigment on uninfected RBCs. Secondarily, we investigated the role of this pigment in formation of endothelial cells-RBCs (EC-RBC) cytoadherence complex. We first observed that a dose dependent hemozoin exposure to uninfected RBCs induced structural abnormalities. Differential counting of these abnormal RBCs indicated population of acanthocytes, spherocytes and microcytes. The formation of abnormal RBCs was observed with phosphatidylserine externalization. Lipid peroxidation, reduced glutathione and reactive oxygen species (ROS) levels indicated an increase in hemozoin exposure mediated oxidative stress. Our in-vitro cytoadherence assay indicated formation of endothelial EC-RBC cytoadherence complex. The dose dependent hemozoin exposure to uninfected RBCs resulted in oxidative stress mediated high order cytoadherence complex formation. This effect was reversed in presence of antioxidant molecules. The inhibitory effect of antioxidant molecules indicates that oxidative stress can be a regulatory factor to control cerebral malaria pathology. Being the first report to highlight the impact of malaria pigment hemozoin on uninfected RBCs, this study brings attention to the role of abnormal RBCs in worsening of cerebral malaria pathology.

Plasmodium falciparum FIKK9.1 is a monomeric serine-threonine protein kinase with features to exploit as a drug target.

FIKK-9.1 is essential for parasite survival, but its structural and biochemical characterization will enable us to understand its role in the parasite life cycle. The recombinant FIKK9.1 kinase is monomeric with a native molecular weight of 60 ± 1.6 kDa. Structural characterization of FIKK9.1 kinase reveals that it consists of two domains: N-terminal FHA like domain and C-terminal kinase domain. The C-terminal domain has a well-defined pocket, but it displayed RMSD deviation of 1.38-3.2 Å from host kinases. ITC analysis indicates that ATP binds to the protein with a Kd of 45.6 ± 2.4 µM. Mutational studies confirm the role of Val-244, Met-245, Lys-320, 324, and Glu-366 for ATP binding. Co-localization studies revealed FIKK9.1 in the parasite cytosol with a component trafficked to the apicoplast and also to IRBC. FIKK9.1 has 23 pockets to serve as potential docking sites for substrates. Correlation analysis of peptides from the combinatorial library concluded that peptide P277 (MFDFHYTLGPMWGTL) was fitting nicely into the binding pocket. The peptide P277 picked up candidates from parasite and key players from RBC cytoskeleton. Interestingly, FIKK9.1 is phosphorylating spectrin, ankyrin, and band-3 from RBC cytoskeleton. Our study highlights the structural and biochemical features of FIKK9.1 to exploit it as a drug target.

Manikya Bhasma is a nanomedicine to affect cancer cell viability through induction of apoptosis.

BACKGROUND: Ayurveda is an ancient medicine system practiced in the Indian sub-continent. Ayurvedic Bhasma is incinerated herbo-metallic/mineral preparations that consist of the particles in the range of nano/micrometers with therapeutic effects against different diseases. Manikya Bhasma (MB) is composed of purified ruby, orpiment, and purified arsenic sulfide. OBJECTIVE: This study was conducted to identify the potential of MB as a nanomedicine that can be used for the treatment of cancer. MATERIALS AND METHODS: Biophysical characterization to determine the morphology and composition of bhasma particles was done using several techniques such as DLS, FTIR, FETEM, FESEM, EDX, and XRD. Cell viability assays were conducted to identify the cytotoxic effect of MB against different cancer cell lines and also to determine the mode of death caused by MB. RESULTS: The biophysical characterization of MB indicates that it is crystalline with a particle size of 70 nm. MB exhibits anticancer activity against MDAMB-231, HeLa, HCT-116, DLD-1, MG-63 cancer cells with an IC50 in the range of 105-155 µg/mL. MB induces oxidative stress in cancer cells, which in turn affects their cell-cycle with an accumulation of cells in the G1-phase. Also, apoptosis induced by MB involves loss of mitochondrial membrane potential, the release of Cyt c, activation of caspases, and DNA degradation. CONCLUSION: Our study highlights the dual potential of MB as a nano-carrier to deliver the drugs and exerting cytotoxic effects against cancer cells.

MycoVarP: Mycobacterium Variant and Drug Resistance Prediction Pipeline for Whole-Genome Sequence Data Analysis.

Whole-genome sequencing (WGS) provides a comprehensive tool to analyze the bacterial genomes for genotype-phenotype correlations, diversity of single-nucleotide variant (SNV), and their evolution and transmission. Several online pipelines and standalone tools are available for WGS analysis of Mycobacterium tuberculosis (Mtb) complex (MTBC). While they facilitate the processing of WGS data with minimal user expertise, they are either too general, providing little insights into bacterium-specific issues such as gene variations, INDEL/synonymous/PE-PPE (IDP family), and drug resistance from sample data, or are limited to specific objectives, such as drug resistance. It is understood that drug resistance and lineage-specific issues require an elaborate prioritization of identified variants to choose the best target for subsequent therapeutic intervention. Mycobacterium variant pipeline (MycoVarP) addresses these specific issues with a flexible battery of user-defined and default filters. It provides an end-to-end solution for WGS analysis of Mtb variants from the raw reads and performs two quality checks, viz, before trimming and after alignments of reads to the reference genome. MycoVarP maps the annotated variants to the drug-susceptible (DS) database and removes the false-positive variants, provides lineage identification, and predicts potential drug resistance. We have re-analyzed the WGS data reported by Advani et al. (2019) using MycoVarP and identified some additional variants not reported so far. We conclude that MycoVarP will help in identifying nonsynonymous, true-positive, drug resistance-associated variants more effectively and comprehensively, including those within the IDP of the PE-PPE/PGRS family, than possible from the currently available pipelines.

Insulin signalling in RBC is responsible for growth stimulation of malaria parasite in diabetes patients.

A cross-talk between diabetes and malaria within-host is well established. Diabetes is associated with modulation of the immune system, impairment of the healing process and to disturb the host metabolism to contribute towards propagation of parasite infection. Glucose metabolism in host is maintained by insulin and RBC has 2000 insulin receptor present on plasma membrane. These receptors are robust to relay down-stream signaling in RBCs but role of intracellular signaling in parasite growth is not been explored. The malaria parasite treated with insulin (100 ng/ml) is giving stimulation in parasite growth. The effect is lasting for several generations resulting into high parasitemia. Insulin signaling is phosphorylating protein in infected RBCs and level is high in parasite RBCs compared to uninfected RBCs. It is phosphorylating Spectrin-(α/ß), Band-4.2, Ankyrin and the other proteins of RBC cytoskeleton. It in-turn induces enhanced glucose uptake inside infected RBCs. There is a high level of infection of normal RBCs by merozoites. In summary, insulin and glucose metabolism plays a crucial role in parasite propagation, disease severity and need consideration while treating patients.

Conformationally constrained peptides for drug delivery.

Peptides have shown great potential in acting as template for developing versatile carrier platforms in nanomedicine, aimed at selective delivery of drugs to only pathological tissues saving its normal neighbors. Cell-penetrating peptides (CPPs) are short oligomeric peptides capable of translocating across the cell membrane while simultaneously employing multiple mechanisms of entry. Most CPPs exist as disordered structures in solution and may adopt a helical conformation on interaction with cell membrane, vital to their penetrative capability. Herein, we report a series of cationic helical amphipathic peptides (CHAPs), which are topologically constrained to be helical. The peptides were tested against cervical and breast cancer cells for their cell penetration and drug delivery potential. The cellular uptake of CHAP peptides is independent of temperature and energy availability. The activity of the peptides is biocompatible in bovine serum. CHAPs delivered functional methotrexate (MTX) inside the cell as CHAP-MTX conjugates. CHAP-MTX conjugates were more toxic to cancer cells than MTX alone. However, the CHAP-MTX conjugates were less toxic to HEK-293 cells compared with the cancer cells suggesting higher affinity towards cancer cells.

Severe malaria: Biology, clinical manifestation, pathogenesis and consequences.

Every year, millions of people are infected with malaria, resulting in significant economic losses to the developing and developed nations. The malaria parasite pursues a complicated life cycle in an invertebrate, mosquito and vertebrate host with several distinct stages. In the human host, it invades the liver and red blood cells to complete its life cycle. It is surprising that not only these two organs are under pressure and exhibit functional abnormalities; a large number of clinical studies also support the notion that malaria parasite propagation in the host affects several other organs and modulates functional outcomes of individual cells. Moreover, patients recovered from severe malaria may suffer throughout their life from impairments in organ function such as loss of eyesight, kidney failure, and much more. Thus, malaria infection leads to several pathological outcomes involving different organs and individual cells in the host. The sole purpose of the present article was to give an overview of pathological outcomes during severe malaria along with their molecular mechanisms. A large proportion of deaths associated with disease is contributed by the pathological effect in host due to parasite propagation and toxicity of antimalarials or combination of both. Hence, there is a need, not only to develop antiparasitic agents but also to discover lead molecules to take care of pathophysiological effects in the host. This may help a beginner to get involved with the topic and initiate research work towards improving adjuvant therapy or avoiding serious complications.

Therapeutic Potentials of Scavenger Receptor CD36 Mediated Innate Immune Responses Against Infectious and Non-Infectious Diseases.

CD36 is a multifunctional glycoprotein, expressed in different types of cells and known to play a significant role in the pathophysiology of the host. The structural studies revealed that the scavenger receptor consists of short cytosolic domains, two transmembrane domains, and a large ectodomain. The ectodomain serves as a receptor for a diverse number of endogenous and exogenous ligands. The CD36-specific ligands are involved in regulating the immune response during infectious and non-infectious diseases in the host. The role of CD36 in regulating the innate immune response during Pneumonia, Tuberculosis, Malaria, Leishmaniasis, HIV, and Sepsis in a ligand- mediated fashion. Apart from infectious diseases, it is also considered to be involved in metabolic disorders such as Atherosclerosis, Alzheimer's, cancer, and Diabetes. The ligand binding to scavenger receptor modulates the CD36 down-stream innate immune response, and it can be exploited to design suitable immuno-modulators. Hence, the current review focused on the role of the CD36 in innate immune response and therapeutic potentials of novel heterocyclic compounds as CD36 ligands during infectious and non-infectious diseases.

A phthalimide-functionalized UiO-66 metal-organic framework for the fluorogenic detection of hydrazine in live cells.

Here, we demonstrated the synthesis, characterization and application of a phthalimide-functionalized UiO-66 metal-organic framework, which showed an intrinsic detection capability for hydrazine. The MOF material (1) was solvothermally prepared by the reaction between ZrCl4 and 2-(1,3-dioxoisoindolin-2-yl)benzene-1,4-dioic acid (H2L) ligand in DMF solvent in the presence of benzoic acid for 48 h at 120 °C. The guest molecule free material (1') was used as a turn-on fluorescent sensor for the selective detection of hydrazine under biological conditions. The phthalimide group anchored in the structure of 1' is converted to the amine group by reaction with hydrazine and this free amine is accountable for the turn-on fluorescence behavior. The probe exhibited an extraordinary detection limit towards hydrazine (0.87 µM). The cellular imaging ability of the MOF probe for hydrazine was also demonstrated with MDAMB-231 breast cancer cells. The probe-loaded cells didn't show considerable cellular cytotoxicity and morphological deformities. They responded towards hydrazine solution by giving an intense blue fluorescent signal. Hence, 1' is capable of monitoring hydrazine in both the aqueous phase and living cells.

Extracellular methemoglobin promotes cyto-adherence of uninfected RBC to endothelial cells: Insight into cerebral malaria pathology.

The endothelial cell barrier is tightly regulated, and disruption or the leaky behavior of the barrier leads to pathology. Disturbance of blood-brain barrier is observed during viral infection, cerebral malaria, and acute hemorrhagic encephalitis. Red blood cells (RBCs) bind to the endothelial cells (ECs) and their affinity towards ECs enhances in the presence of Plasmodium falciparum infection. ECs stimulated with methemoglobin (MetHb; 20 µM) for 1 hour exhibit high levels of cyto-adherence receptors CD36 and ICAM-1 on their cell surface compared with unstimulated cells. These ECs have acquired affinity towards uninfected RBCs in flow at arterial shear stress. SEM analysis indicates that EC-RBC cyto-adherence involved multiple attachment points. Initially, ECs bind single layer of RBCs and the number of RBCs increases over time to give high-order cyto-adherence with more than 30 RBCs adhered to each endothelial cell. The cyto-adherence complexes are stable to high shear stress and can withstand shear stress up to 450 dyne/cm 2 . MetHb-treated ECs exhibited high reactive oxygen species level, and preincubation of ECs with antioxidant (NAC or mannitol) abolished the formation of EC-RBC cyto-adherence complexes. In addition, gallic acid (present in red wine) and green tea extract has inhibited the formation of EC-RBC cyto-adherence complex. A better understanding of gallic acid and tea polyphenol targeting pathological cyto-adherence may allow us to develop a better adjuvant therapy for cerebral malaria and other noninfectious diseases.