The Drp1-Mediated Mitochondrial Fission Protein Interactome as an Emerging Core Player in Mitochondrial Dynamics and Cardiovascular Disease Therapy.

Mitochondria, the membrane-bound cell organelles that supply most of the energy needed for cell function, are highly regulated, dynamic organelles bearing the ability to alter both form and functionality rapidly to maintain normal physiological events and challenge stress to the cell. This amazingly vibrant movement and distribution of mitochondria within cells is controlled by the highly coordinated interplay between mitochondrial dynamic processes and fission and fusion events, as well as mitochondrial quality-control processes, mainly mitochondrial autophagy (also known as mitophagy). Fusion connects and unites neighboring depolarized mitochondria to derive a healthy and distinct mitochondrion. In contrast, fission segregates damaged mitochondria from intact and healthy counterparts and is followed by selective clearance of the damaged mitochondria via mitochondrial specific autophagy, i.e., mitophagy. Hence, the mitochondrial processes encompass all coordinated events of fusion, fission, mitophagy, and biogenesis for sustaining mitochondrial homeostasis. Accumulated evidence strongly suggests that mitochondrial impairment has already emerged as a core player in the pathogenesis, progression, and development of various human diseases, including cardiovascular ailments, the leading causes of death globally, which take an estimated 17.9 million lives each year. The crucial factor governing the fission process is the recruitment of dynamin-related protein 1 (Drp1), a GTPase that regulates mitochondrial fission, from the cytosol to the outer mitochondrial membrane in a guanosine triphosphate (GTP)-dependent manner, where it is oligomerized and self-assembles into spiral structures. In this review, we first aim to describe the structural elements, functionality, and regulatory mechanisms of the key mitochondrial fission protein, Drp1, and other mitochondrial fission adaptor proteins, including mitochondrial fission 1 (Fis1), mitochondrial fission factor (Mff), mitochondrial dynamics 49 (Mid49), and mitochondrial dynamics 51 (Mid51). The core area of the review focuses on the recent advances in understanding the role of the Drp1-mediated mitochondrial fission adaptor protein interactome to unravel the missing links of mitochondrial fission events. Lastly, we discuss the promising mitochondria-targeted therapeutic approaches that involve fission, as well as current evidence on Drp1-mediated fission protein interactions and their critical roles in the pathogeneses of cardiovascular diseases (CVDs).

Therapeutic considerations related to stress levels associated with hand eczema: A clinico-etiological study.

Understanding the etiological factors, stress and quality of life have important implications in the management. There is dearth of the literature in this subject, assessing the stress levels in hand eczema and disparities exist in results of the available literature. Primary objective of this study is to assess the clinico-etiological factors in cases of hand eczema. The secondary objectives include to find any correlation between morphological types and the etiological factors, and to determine the role of stress level in these patients. Patients with hand eczema who attended the outpatient department of our tertiary care institution were enrolled in this descriptive study. Sociodemographic and clinico-etiologic data were collected and patch testing of all patients were done. Stress levels were assessed with Perceived stress scale (PSS). Among the 62 patients enrolled, allergic contact dermatitis predominated with 37 (59.7%) cases and patch test was positive in 41 (66.1%). Potassium dichromate was the most common allergen in males, and fragrance mix in females. Significant levels of stress were seen in 67.7% of the subjects. There was no significant correlation between morphological subtypes and the identified aetiologies. Hand eczema is most commonly due to allergic contact dermatitis, and patch testing is helpful in reaching an etiological diagnosis in most of the cases. A large proportion of patients have high stress levels, and hence stress management should also be a part of treatment in addition to traditional treatment.

Rational design, synthesis and structural characterization of peptides and peptidomimetics to target Hsp90/Cdc37 interaction for treating hepatocellular carcinoma.

Heat shock protein 90 (Hsp90) and cell division cycle 37 (Cdc37) work together as a molecular chaperone complex to regulate the activity of a multitude of client protein kinases. These kinases belong to a wide array of intracellular signaling networks that mediate multiple cellular processes including proliferation. As a result, Hsp90 and Cdc37 represent innovative therapeutic targets in various cancers (such as leukemia, multiple myeloma, and hepatocellular carcinoma (HCC)) in which their expression levels are elevated. Conventional small molecule Hsp90 inhibitors act by blocking the conserved adenosine triphosphate (ATP) binding site. However, by targeting less conserved sites in a more specific manner, peptides and peptidomimetics (modified peptides) hold potential as more efficacious and less toxic alternatives to the conventional small molecule inhibitors. Using a rational approach, we herein developed bioactive peptides targeting Hsp90/Cdc37 interaction. A six amino acid linear peptide derived from Cdc37, KTGDEK, was designed to target Hsp90. We used in silico computational docking to first define its mode of interaction, and binding orientation, and then conjugated the peptide with a cell penetrating peptide, TAT, and a fluorescent dye to confirm its ability to colocalize with Hsp90 in HCC cells. Based on the parent linear sequence, we developed a peptidomimetics library of pre-cyclic and cyclic derivatives. These peptidomimetics were evaluated for their binding affinity to Hsp90, and bioactivity in HCC cell lines. Among them, a pre-cyclic peptidomimetic demonstrates high binding affinity and bioactivity in HCC cells, causing reduced cell proliferation that is associated with induction of cell apoptosis, and down-regulation of phosphorylated MEK1/2. Overall, this generalized approach of rational design, structural optimization, and cellular validation of 'drug-like' peptidomimetics against Hsp90/Cdc37 offers a feasible and promising way to design novel therapeutic agents for malignancies and other diseases that are dependent on this molecular chaperone complex.

Exploring Biomolecular Interaction Between the Molecular Chaperone Hsp90 and Its Client Protein Kinase Cdc37 using Field-Effect Biosensing Technology.

Biomolecular interactions play versatile roles in numerous cellular processes by regulating and coordinating functionally relevant biological events. Biomolecules such as proteins, carbohydrates, vitamins, fatty acids, nucleic acids, and enzymes are fundamental building blocks of living beings; they assemble into complex networks in biosystems to synchronize a myriad of life events. Proteins typically utilize complex interactome networks to carry out their functions; hence it is mandatory to evaluate such interactions to unravel their importance in cells at both cellular and organism levels. Toward this goal, we introduce a rapidly emerging technology, field-effect biosensing (FEB), to determine specific biomolecular interactions. FEB is a benchtop, label-free, and reliable biomolecular detection technique to determine specific interactions and uses high-quality electronic-based biosensors. The FEB technology can monitor interactions in the nanomolar range due to the biocompatible nanomaterials used on its biosensor surface. As a proof of concept, the protein-protein interaction (PPI) between heat shock protein 90 (Hsp90) and cell division cycle 37 (Cdc37) was elucidated. Hsp90 is an ATP-dependent molecular chaperone that plays an essential role in the folding, stability, maturation, and quality control of many proteins, thereby regulating multiple vital cellular functions. Cdc37 is regarded as a protein kinase-specific molecular chaperone, as it specifically recognizes and recruits protein kinases to Hsp90 to regulate their downstream signal transduction pathways. As such, Cdc37 is considered a co-chaperone of Hsp90. The chaperone-kinase pathway (Hsp90/Cdc37 complex) is hyper-activated in multiple malignancies promoting cellular growth; therefore, it is a potential target for cancer therapy. The present study demonstrates the efficiency of FEB technology using the Hsp90/Cdc37 model system. FEB detected a strong PPI between the two proteins (KD values of 0.014 µM, 0.053 µM, and 0.072 µM in three independent experiments). In summary, FEB is a label-free and cost-effective PPI detection platform, which offers fast and accurate measurements.

COVID-19 Pandemic: Preparing to Care for Patients With Cancer From the Perspective of Low- and Middle-Income Countries.

As the coronavirus spread from Asia to Western Europe and North America, healthcare institutions in the Middle East, Africa, South Asia, and Latin America prepared for the COVID-19 pandemic. Interprofessional task forces were established to coordinate institutions' responses, inventory supplies of personal protective equipment, educate staff and patients, develop procedures for triaging patients and prioritizing care, and provide support to nurses to mitigate their stress. Despite challenges, nurses continued to deliver quality care to patients with cancer.

Quercetin binding to Spatholobus parviflorus lectin: Promise of a macromolecular, specific-compound carrier for drug.

Glycan recognition is the most attractive defining feature of lectins, and also they exhibit specific phytochemical interactions at distinct sites without interfering the glycocode recognition capability. These additional sites may be viewed as potential drug carrying sites that could be exploited for targeted drug delivery. The pharmacological effects of quercetin (QN) have already been studied. However, its molecular mechanism of interactions with lectin has not yet been addressed. The extending novelty provokes us to unravel the binding profile of QN with Spatholobus parviflorus lectin (SPL) using a combination series of biophysical and computational approaches. The UV absorption studies revealed an intense SPL-QN complex formation, indicating a hyperchromic effect. The fluorescence spectroscopic analysis using sugar-free SPL and sugar saturated SPL (ssSPL) revealed that QN binding significantly quenched the intrinsic fluorescence of SPL. The thermodynamic parameters maintained uniformity with the binding stoichiometry (n = 4) of both SPL and ssSPL, hence it may be assumed that the sugar binding onto the SPL would not have been influenced with QN binding. The molecular docking analysis also maintained consistency with the in vitro results. It could be concluded from SPL-QN interactions without altering unique carbohydrate specificities, leave SPL unrestricted for other molecular recognition events.

Photophysical and thermodynamic evaluation on the in vitro and in silico binding profile of Camptothecin with DNA.

Camptothecin (CMT) is an anti-tumour alkaloid drug exhibiting selective topoisomerase-I inhibitory activity by eventually hindering dynamic functions of DNA duplex via initiating apoptosis. Unravelling the binding mechanism of CMT with bio macromolecular systems can offer fundamental information regarding the mechanism of actions which can lead to the design of rational proactive drugs. This study endeavoured the binding interactions of CMT with calf thymus DNA (ct-DNA) along with the structural alterations attained by the DNA duplex owing to CMT interactions through multi-spectroscopic, calorimetric and molecular docking studies. The UV-visible absorbance and fluorescence quenching studies revealed the binding strength of CMT with ct-DNA, evident from the binding constants K1 = 3.79 × 103 M-1 and Kq = 2 × 103 M-1. The time-resolved lifetime measurements inferred that the quenching was static due to the non-fluorescent ground state complex formation. The dye displacement study, temperature melting and viscosity measurements established a typical non-intercalative binding mode of CMT with ct-DNA. The binding isotherm deduced from ITC was found to be spontaneous and exothermic exerting a promising ΔG value of -6.2 kcal mol-1. The thermal kinetic parameters implied that the forces primarily involved in the CMT-ct-DNA complexation are hydrogen bonding and van der Waals interactions. Moreover, the structural alterations of DNA duplex reflected in the CD and FTIR spectra could undeniably confirm the groove binding manner of CMT. The in silico extra precision docking study explored more accurate molecular illustrations of sequence specific minor groove binding mechanism evolved between CMT and DNA corroborating well with the experimental results. These innovative findings may shorten the path towards the development of novel and more effective CMT drug derivatives.