Prevention of ribosome collision-induced neuromuscular degeneration by SARS CoV-2-encoded Nsp1.

An overarching goal of aging and age-related neurodegenerative disease research is to discover effective therapeutic strategies applicable to a broad spectrum of neurodegenerative diseases. Little is known about the extent to which targetable pathogenic mechanisms are shared among these seemingly diverse diseases. Translational control is critical for maintaining proteostasis during aging. Gaining control of the translation machinery is also crucial in the battle between viruses and their hosts. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing COVID-19 pandemic. Here, we show that overexpression of SARS-CoV-2-encoded nonstructural protein 1 (Nsp1) robustly rescued neuromuscular degeneration and behavioral phenotypes in Drosophila models of Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. These diseases share a common mechanism: the accumulation of aberrant protein species due to the stalling and collision of translating ribosomes, leading to proteostasis failure. Our genetic and biochemical analyses revealed that Nsp1 acted in a multipronged manner to resolve collided ribosomes, abort stalled translation, and remove faulty translation products causative of disease in these models, at least in part through the ribosome recycling factor ABCE1, ribosome-associated quality-control factors, autophagy, and AKT signaling. Nsp1 exhibited exquisite specificity in its action, as it did not modify other neurodegenerative conditions not known to be associated with ribosome stalling. These findings uncover a previously unrecognized mechanism of Nsp1 in manipulating host translation, which can be leveraged for combating age-related neurodegenerative diseases that are affecting millions of people worldwide and currently without effective treatment.

In vitro and in vivo studies on potentiation of curcumin-induced lysosomal-dependent apoptosis upon silencing of cathepsin C in colorectal cancer cells.

Cathepsins are lysosomal acid hydrolases that make crucial contributions to tumor progression through a variety of signaling mechanisms, including autophagy, cell survival, chemotherapeutic resistance, and metastasis. Herein, we report that cathepsin C (CTSC) silencing upregulates the anticancer potential of curcumin in colorectal cancer cells (CRCs) both in vitro and in athymic mice xenografts. Curcumin treatment enhances CTSC level in CRCs; however, CTSC silencing with subsequent curcumin treatment (sequential treatment) induces ER stress and autophagic dysregulation accompanied by lysosomal permeabilization and ROS generation. This lysosomal permeabilization triggered the cytosolic CTSB mediated BID-dependent mitochondrial membrane permeabilization and thereby caspase-dependent apoptosis. This phenotype can be rescued by CTSB inhibition and NAC, which further supported the involvement of ROS and CTSB in apoptosis following sequential treatment. Indeed, the sequential CTSC silencing and curcumin treatment also significantly curtailed tumor volume as well as ameliorated cytosolic cyt c and tBID protein levels in tumor tissues compared to those in control and individual treatments of CTSC targeting and on curcumin treatment in nude mice xenografts. The results reveal that CTSC can controls the curcumin-induced cytotoxic insult through autophagy maintenance both in vitro and in athymic mice xenografts, thereby providing an insight into the role of CTSC in chemoprevention of CRCs.

Purification and biochemical characterization of dipeptidyl peptidase-II (DPP7) homologue from germinated Vigna radiata seeds.

Dipeptidyl peptidases (DPPs) are potent exopeptidases, which possess central role in proteolysis. As compared to other members of DPP family, proline containing dipeptide hydrolysing activity of DPP-II (Dipeptidyl peptidase II) is unique as it hydrolyses imino group and plays a key role in protein metabolism. In present study, DPP-II was purified from germinated moong bean seeds using acid and ammonium sulphate precipitation followed by successive chromatographies on gel filtration (pH 7.4) and cation exchanger (pH 5.9). Native PAGE and in-situ gel assay confirmed the apparent homogeneity. Purified plant DPP-II is an oligomeric enzyme with molecular weight of 97.3kDa. Highest DPP-II activity was observed at pH 7.5 and 37°C, with stability in the range of neutral to alkaline pH. Substrate specificity showed consequent activity for proline containing dipeptide followed by Lys-Ala and other hydrophobic dipeptides, but none of the studied endopeptidase and monopeptidase substrate was hydrolysed. Catalytic characterization with modifier studies revealed the involvement of Ser and His residues in its catalytic mechanism. Its dipeptidyl peptidase activity for proline containing dipeptide supported its role in the bioactive peptide generation and food industry. Functional studies of DPP-II revealed the significant involvement of this glycoproteinous enzyme in protein mobilization during germination. Further studies on industrial applications exploring physiological role are in progress.

Biochemical and physiological studies on the effects of senescence leaves of Populus deltoides on Triticum vulgare.

Triticum vulgare (Wheat) based products are the major dietary source of food in developing countries. In India, it grows in association with boundary plantations of Populus deltoids (poplar). During winter, poplar enters in dormancy which cause a heavy leaf fall at the time of wheat seed germination. Large number of poplar senescence leaves may adversely affect the wheat. Therefore, the present study was performed to examine the effect of senescence poplar leaves on wheat germ and some other biochemical parameters. Seed's germination rate was determined by measuring root and shoot lengths, percent germination, germination index, and inhibition percentage. Biochemical parameters, namely, pigment, carbohydrate, protein, and phenol content, were estimated. Activities of catalase and polyphenol oxidase which are stress marker enzymes were also measured. Results revealed that germination and other biochemical parameters of wheat were severely affected by senescence poplar leaves even at very low concentration. So, intercropping of poplar along with wheat may be chosen carefully as wheat is the major dietary staple.

Ribosome stalling during c-myc translation presents actionable cancer cell vulnerability.

Myc is a major driver of tumor initiation, progression, and maintenance. Up-regulation of Myc protein level rather than acquisition of neomorphic properties appears to underlie most Myc-driven cancers. Cellular mechanisms governing Myc expression remain incompletely defined. In this study, we show that ribosome-associated quality control (RQC) plays a critical role in maintaining Myc protein level. Ribosomes stall during the synthesis of the N-terminal portion of cMyc, generating aberrant cMyc species and necessitating deployment of the early RQC factor ZNF598 to handle translational stress and restore cMyc translation. ZNF598 expression is up-regulated in human glioblastoma (GBM), and its expression positively correlates with that of cMyc. ZNF598 knockdown inhibits human GBM neurosphere formation in cell culture and Myc-dependent tumor growth in vivo in Drosophila. Intriguingly, the SARS-COV-2-encoded translational regulator Nsp1 impinges on ZNF598 to restrain cMyc translation and consequently cMyc-dependent cancer growth. Remarkably, Nsp1 exhibits synthetic toxicity with the translation and RQC-related factor ATP-binding cassette subfamily E member 1, which, despite its normally positive correlation with cMyc in cancer cells, is co-opted by Nsp1 to down-regulate cMyc and inhibit tumor growth. Ribosome stalling during c-myc translation thus offers actionable cancer cell vulnerability.

Anaplastic thyroid cancer spheroids as preclinical models to test therapeutics.

Anaplastic thyroid cancer (ATC) is the most aggressive thyroid cancer. Despite advances in tissue culture techniques, a robust model for ATC spheroid culture is yet to be developed. In this study, we created an efficient and cost-effective 3D tumor spheroids culture system from human ATC cells and existing cell lines that better mimic patient tumors and that can enhance our understanding of in vivo treatment response. We found that patient-derived ATC cells and cell lines can readily form spheroids in culture with a unique morphology, size, and cytoskeletal organization. We observed both cohesive (dense and solid structures) and discohesive (irregularly shaped structures) spheroids within the same culture condition across different cell lines. BRAFWT ATC spheroids grew in a cohesive pattern, while BRAFV600E-mutant ATC spheroids had a discohesive organization. In the patient-derived BRAFV600E-mutant ATC spheroids, we observed both growth patterns, but mostly the discohesive type. Histologically, ATC spheroids had a similar morphology to the patient's tumor through H&E staining and proliferation marker staining. Moreover, RNA sequencing analysis revealed that the gene expression profile of tumor cells derived from the spheroids closely matched parental patient tumor-derived cells in comparison to monolayer cultures. In addition, treatment response to combined BRAF and MEK inhibition in BRAFV600E-mutant ATC spheroids exhibited a similar sensitivity to the patient clinical response. Our study provides a robust and novel ex vivo spheroid model system that can be used in both established ATC cell lines and patient-derived tumor samples to better understand the biology of ATC and to test therapeutics.

Deregulation of ER-mitochondria contact formation and mitochondrial calcium homeostasis mediated by VDAC in fragile X syndrome.

Loss of fragile X messenger ribonucleoprotein (FMRP) causes fragile X syndrome (FXS), the most prevalent form of inherited intellectual disability. Here, we show that FMRP interacts with the voltage-dependent anion channel (VDAC) to regulate the formation and function of endoplasmic reticulum (ER)-mitochondria contact sites (ERMCSs), structures that are critical for mitochondrial calcium (mito-Ca2+) homeostasis. FMRP-deficient cells feature excessive ERMCS formation and ER-to-mitochondria Ca2+ transfer. Genetic and pharmacological inhibition of VDAC or other ERMCS components restored synaptic structure, function, and plasticity and rescued locomotion and cognitive deficits of the Drosophila dFmr1 mutant. Expressing FMRP C-terminal domain (FMRP-C), which confers FMRP-VDAC interaction, rescued the ERMCS formation and mito-Ca2+ homeostasis defects in FXS patient iPSC-derived neurons and locomotion and cognitive deficits in Fmr1 knockout mice. These results identify altered ERMCS formation and mito-Ca2+ homeostasis as contributors to FXS and offer potential therapeutic targets.

N-Acetyldopamine dimers from Oxya chinensis sinuosa attenuates lipopolysaccharides induced inflammation and inhibits cathepsin C activity.

Oxya chinensis sinuosa (rice field grasshopper) is an edible insect with numerous health beneficial properties, traditionally being used to treat many ailments in Korea and other countries. O. chinensis sinuosa has been used from centuries, however, a little is known about the chemical functionality of its bioactive compounds. Therefore, this study examined the anti-inflammatory and cathepsin C inhibitory activities of N-acetyldopamine dimer (2R, 3S)-2-(3',4'-dihydroxyphenyl)-3-acetylamino-7-(N-acetyl-2″-aminoethyl)-1,4-benzodioxane (DAB1) isolated from O. chinensis sinuosa. Results showed that DAB1 reduced the expression of pro-inflammatory mediator (iNOS, COX-2) and cytokines (TNF-α, IL-1ß, and IL-6), and curtailed the nuclear translocation of NF-κB by inhibiting the phosphorylation of IκBα in lipopolysaccharide stimulated macrophages. Additionally, DAB1 inhibited cathepsin C activity at the cellular level, supported by in vitro assay (Ki, 71.56 ± 10.21 µM and Kis, 133.55 ± 18.2 µM). Moreover, combinatorial molecular simulation and binding free energy analysis suggested a significant stability and binding affinity of cathepsin C-DAB1 complex via formation of hydrogen bond and hydrophobic interactions with the catalytic residues (Gln228, Thr379, Asn380, and Hie381). Also, essential dynamics analysis showed DAB1 induced non-functional motions in cathepsin C structure. Collectively, DAB1 was concluded as anti-inflammatory and cathepsin C inhibiting agent and could be used in the drug development against respective diseases.

The Potential of Receptor for Advanced Glycation End Products (RAGE) as a Therapeutic Target for Lung Associated Diseases.

The receptor for advanced glycation end products (RAGE) is a multi-ligand pattern recognition receptor that is highly expressed in lung epithelial cells. It helps alveolar epithelial cells to maintain their morphology and specific architecture. However, in various pathophysiological conditions, pulmonary tissues express a supraphysiological level of RAGE and its ligands including advanced glycation end products, high mobility group box 1 proteins, and S100 proteins. On interaction with RAGE, these ligands stimulate downstream signaling that generates inflammation and oxidative stress leading to asthma, chronic obstructive pulmonary disease, lung cancers, idiopathic pulmonary fibrosis, acute lung injury, pneumonia, bronchopulmonary dysplasia, cystic fibrosis, and sepsis. Thus, pharmacological agents that can either suppress the production of RAGE or block its biological activity would offer promising therapeutic value against pathogenesis of the aforementioned lungassociated diseases. This review presents a comprehensive overview of the recent progress made in defining the functions of RAGE in lung-associated diseases.

Cathepsins: Potent regulators in carcinogenesis.

Cathepsins (CTS) are mainly lysosomal acid hydrolases extensively involved in the prognosis of different diseases, and having a distinct role in tumor progression by regulating cell proliferation, autophagy, angiogenesis, invasion, and metastasis. As all these processes conjunctively lead to cancer progression, their site-specific regulation might be beneficial for cancer treatment. CTS regulate activation of the proteolytic cascade and protein turnover, while extracellular CTS is involved in promoting extracellular matrix degradation and angiogenesis, thereby stimulating invasion and metastasis. Despite cancer regulation, the involvement of CTS in cellular adaptation toward chemotherapy and radiotherapy augments their therapeutic potential. However, lysosomal permeabilization mediated cytosolic translocation of CTS induces programmed cell death. This complex behavior of CTS generates the need to discuss the different aspects of CTS associated with cancer regulation. In this review, we mainly focused on the significance of each cathepsin in cancer signaling and their targeting which would provide noteworthy information in the context of cancer biology and therapeutics.

Targeting of cathepsin C induces autophagic dysregulation that directs ER stress mediated cellular cytotoxicity in colorectal cancer cells.

As Autophagy is a pivotal mechanism of cancer cell survival and the development of chemotherapeutic resistance; therefore, new approaches are warranted for its targeting which may be fulfilled by cathepsins regulation. Amongst cathepsins, cathepsin C (CTSC) is highly expressed in various cancers and possesses significant therapeutic potential in autoimmune disorders; however, its role in colorectal cancer has not been explored. Herein, we aimed to investigate the role of CTSC in autophagy regulation mediated colorectal carcinoma cell proliferation. Cathepsin C targeting through inhibitors/siRNA leads to the accumulation of light chain 3 II and p62 without affecting the lysosomal integrity, revealed dysfunctional autolysosomal degradation which is also substantiated by proteolytic studies. Cathepsin C inhibition showed comparable autophagy blockade with E64d and augmented the autophagy blockade mediated by bafilomycin. Loss of CTSC function also induced ER stress-mediated JNK phosphorylation accompanied by the translocation of mitochondrial cyt c followed by apoptotic cell death in colorectal carcinoma cells. Taken together, the study reveals that CTSC targeting plays a key role in the regulation of autophagy mediated colorectal cancer cell proliferation. Further investigations are required to determine the functional role of CTSC in other tumors also which may have implications for the therapeutic prevention of cancer in the future.

CJK-7, a Novel Flavonoid from Paulownia tomentosa Triggers Cell Death Cascades in HCT-116 Human Colon Carcinoma Cells via Redox Signaling.

BACKGROUND: Colon cancer is the second most common cancer to cause death worldwide. About half of colon cancers patients require adjuvant therapy to control relapse following surgical resection. Therefore, abolition of tumor cell progression using an effective chemotherapeutic agent holds a feasible approach to treat patients suffering from colon cancer. In the present study, we evaluated the effects of geranylated flavonoid CJK-7, isolated from Paulownia tomentosa on HCT-116 human colon carcinoma cells. MATERIALS AND METHODS: The effects of CJK-7 as an active component on HCT-116 cells programmed cell death and its underlying molecular mechanism were examined by using MTT assay, morphological assessment, H2DCFDA staining, Fura-2AM staining, Hoechst-33342 staining, comet assay, Acridine orange staining, mitochondrial membrane potential (ΔΨm) assay and Western blot analyses. RESULTS AND CONCLUSION: The results revealed that, CJK-7 was capable of inducing caspase-dependent cell death events in cancer cells. Moreover, it was involved in up-regulation of autophagy signaling as evidenced by enhanced expression of LC3I/II. We also noticed stimulated expression of endoplasmic reticulum stress markers and phosphorylation of c-Jun NH2-terminal kinase (JNK), which was associated with up-regulated expression of p53, PUMA, Atg5 and Beclin-1, and down-regulation of Bcl-2, stressing the interaction of ROS on the aforementioned signaling. Furthermore, exposure to ROS scavengers (N-acetyl-l-cysteine (NAC), and JNK-specific inhibitor SP600125) significantly reversed the effects of CJK-7 by down-regulating apoptosis and autophagy signatures in HCT-116 cancer cells. Collectively our findings clarify the ROS-dependent regulatory effect of CJK-7 on programmed cell death signaling events in HCT-116 cancer cells while depicting its virile pro-oxidant capacity.

Vitexin induces apoptosis by suppressing autophagy in multi-drug resistant colorectal cancer cells.

Cancer treatment is limited due to the diverse multidrug resistance acquired by cancer cells and the collateral damage caused to adjacent normal cells by chemotherapy. The flavonoid compound vitexin exhibits anti-oxidative, anti-inflammatory and anti-tumor activity. This study elucidated the antitumor effects of vitexin and its underlying mechanisms in a multi-drug resistant human colon cancer cell line (HCT-116DR), which exhibits higher levels of multidrug-resistant protein 1 (MDR1) expression as compared with its parental cell line (HCT-116). Here, we observed that vitexin suppressed MDR-1 expression and activity in HCT-116DR cells and showed cytotoxic effect in HCT-116DR cells by inhibiting autophagy and inducing apoptosis in a concentration-dependent manner. Additionally, vitexin treatment caused cleavage of caspase-9 and caspase-3, and upregulated the expression of the pro-apoptotic proteins, BID and Bax. Moreover, the expression of autophagy-related proteins, such as ATG5, Beclin-1 and LC3-II, was markedly reduced by vitexin treatment. Furthermore, in vivo experiments showed that vitexin induced apoptosis and suppressed tumor growth in HCT-116DR xenograft model. These results revealed that vitexin induced apoptosis through suppression of autophagy in vitro and in vivo and provide insight into the therapeutic potential of vitexin for the treatment of chemo-resistant colorectal cancer.

Breast cancer metastasis: Putative therapeutic role of vascular cell adhesion molecule-1.

BACKGROUND: Breast cancer is a notable cause of cancer-related death in women worldwide. Metastasis to distant organs is responsible for ~90% of this death. Breast cells convert to malignant cancer cells after acquiring the capacity of invasion/intravasation into surrounding tissues and, finally, extravasation/metastasis to distant organs (i.e., lymph nodes, lungs, bone, brain). Metastasis to distant organs depends on interactions between disseminated tumor cells (DTCs) and the endothelium of blood vessels present in the tumor microenvironment. Among several known endothelial adhesion molecules, vascular cell adhesion molecule-1 (VCAM-1) has been found to be involved in this process. It has been shown that VCAM-1 is aberrantly expressed in breast cancer cells and that it can bind to its natural ligand α4ß1integrin, also denoted as very late antigen 4 (VLA-4). This binding appears to be responsible for the metastasis of breast cancer cells to lung, bone and brain. The α4ß1 integrin - VCAM-1 interaction thus represents a potential therapeutic target for metastatic breast cancer cells. The development of inhibitors of this interaction may be instrumental for the clinical management of breast cancer patients. CONCLUSIONS: This study focuses on recent progress on the role of VCAM-1, an important glycoprotein belonging to the immunoglobulin (Ig) superfamily of cell surface adhesion molecules in breast cancer angiogenesis, survival and metastasis. Targeting VCAM-1, expressed on the surface of breast cancer cells, and/or its specific ligand VLA-4/α4ß1 integrin, expressed on cells at the site of metastasis, may be a useful strategy to reduce breast cancer cell invasion and metastasis. Various approaches to therapeutically target VCAM-1 and VLA-4 are also discussed.

Enkephalin degrading enzymes: metalloproteases with high potential for drug development.

Enkephalins play a great role in management of pain, blood pressure, hypertension and cardiovascular diseases. Enkephalins are short-lived molecules being rapidly hydrolyzed following their synaptic release by enkephalin degrading enzymes. The inhibitors of enkephalin degrading enzymes are able to prolong the duration of action of enkephalins. This review will focus on the inhibitors of enkephalin degrading enzymes as a novel therapeutic approach for cancer itself and also in cancer and neuropathic pain management with discussion on the present status and future directions for a new class of drugs.

Biochemical characterization of consortium compost of toxic weeds Parthenium hysterophorus and Eichhornia crassipe.

Parthenium hysterophorus and Eichhornia crassipes are two uncontrolled weeds with high concentration of N, P, K, Zn and Fe that makes them suitable for composting. Three types of compost viz. Parthenium and Eichhornia each alone as well as combined were prepared. Biochemical and enzymatic analysis of the compost in addition to seed germination was performed. Phenols, organic carbon, C/N and C/P ratios were found to decrease significantly while N, P, K, polyphenol oxidase increased significantly in combined compost. Furthermore, seed germination test of Vigna radiata and Triticum seeds, revealed a significant increase in root, shoot length and germination index in 60days old combined compost. It can be concluded that combined composting of Parthenium with Eichhornia not only reduces the allelopathic effect but also increases its nutrient quality and thus could be promising for organic farming and bioremediation.

Biochemical studies on hemoglobin modified with reactive oxygen species (ROS).

Hemoglobin is the iron-containing oxygen transporting metalloprotein in the red cells of blood in mammals and other animals. Hemoprotein-mediated oxidative stress is thought to play a major role in pathophysiology of cerebral hemorrhage, blast pressure injury, crush injury, myocardial ischemia reperfusion injury. Hemoglobin undergoes oxidation-reduction reactions that lead to both generation and consumption of highly reactive oxygen and nitrogen species. In the present study, hemoglobin molecule was treated with hydrogen peroxide and the modification so incurred was analyzed by UV spectra, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and detection of carbonyl content. Our observations suggest that carbonyl content increases with increase in concentration of hydrogen peroxide. Production of hydroxyl radical was assessed by using benzoate degradation analysis. Our results was in tandem with the fact that hemoglobin on treatment with hydrogen peroxide rapidly generates free-radical species that can degrade benzoate to thiobarbituric acid reactive material which on reacting with thiobarbituric acid gives color. The increase in absorbance of ROS-modified hemoglobin at 532 nm shows the increase in benzoate degradation, which is a parameter of hydroxyl radical formation with increase in concentration of hydrogen peroxide. Modified hemoglobin was treated with catalase, mannitol, thiourea, glutathion, sodium benzoate and their effect were detected by spectroscopy and SDS-PAGE (12%). Substantial scavenging effect of aforementioned antioxidants reiterates the formation of hydroxyl radical. Catalase shows the maximum scavenging effect followed by thiourea and mannitol.