Chemokine receptor CXCR7 activates Aurora Kinase A and promotes neuroendocrine prostate cancer growth.

CXCR7 is an atypical chemokine receptor that recruits ß-arrestin (ARRB2) and internalizes into clathrin-coated intracellular vesicles where the complex acts as a scaffold for cytoplasmic kinase assembly and signal transduction. Here, we report that CXCR7 was elevated in the majority of prostate cancer (PCa) cases with neuroendocrine features (NEPC). CXCR7 markedly induced mitotic spindle and cell cycle gene expression. Mechanistically, we identified Aurora Kinase A (AURKA), a key regulator of mitosis, as a novel target that was bound and activated by the CXCR7-ARRB2 complex. CXCR7 interacted with proteins associated with microtubules and golgi, and, as such, the CXCR7-ARRB2-containing vesicles trafficked along the microtubules to the pericentrosomal golgi apparatus, where the complex interacted with AURKA. Accordingly, CXCR7 promoted PCa cell proliferation and tumor growth, which was mitigated by AURKA inhibition. In summary, our study reveals a critical role of CXCR7-ARRB2 in interacting and activating AURKA, which can be targeted by AURKA inhibitors to benefit a subset of patients with NEPC.

Ferroptosis: the vulnerability within a cancer monster.

Treatment-resistant cancer, such as neuroendocrine prostate cancer (NEPC), is a lethal disease with limited therapeutic options. RB1 is a tumor suppressor gene that is lost in a majority of NEPC tumors. In this issue of the JCI, Wang and colleagues examined how RB1 loss may sensitize cancer cells to ferroptosis inducers through elevation of ACSL4, a key enzyme that promotes lipid peroxidation and triggers ferroptosis. We discuss a high potential of RB1-deficient cells to undergo ferroptosis due to the elevation of ACSL4. This is normally kept in check by abundant expression of GPX4, an antioxidant enzyme, in cancer cells. This balance, however, is tilted by GPX4 inhibitors, leading to massive ferroptosis. We highlight possible therapeutic strategies that exploit this inherent vulnerability for targeting RB1-deficient, treatment-resistant cancer.

Palmitoyl acyltransferase ZDHHC7 inhibits androgen receptor and suppresses prostate cancer.

The hormonal transcription factor androgen receptor (AR) is a master regulator of prostate cancer (PCa). Protein palmitoylation, which attaches a palmitate fatty acid to a substrate protein, is mediated by a class of 23 ZDHHC (Zinc-Finger DHHC motif)-family palmitoyltransferases. Although palmitoylation has been shown to modify many proteins and regulate diverse cellular processes, little is known about ZDHHC genes in cancer. Here we examined ZDHHC family gene expression in human tissue panels and identified ZDHHC7 as a PCa-relevant member. RNA-seq analyses of PCa cells with ZDHHC7 de-regulation revealed global alterations in androgen response and cell cycle pathways. Mechanistically, ZDHHC7 inhibits AR gene transcription and therefore reduces AR protein levels and abolishes AR signaling in PCa cells. Accordingly, ZDHHC7 depletion increased the oncogenic properties of PCa cells, whereas restoring ZDHHC7 is sufficient to suppress PCa cell proliferation and invasion in vitro and mitigate xenograft tumor growth in vivo. Lastly, we demonstrated that ZDHHC7 is downregulated in human PCa compared to benign-adjacent tissues, and its loss is associated with worse clinical outcomes. In summary, our study reveals a global role of ZDHHC7 in inhibiting androgen response and suppressing PCa progression and identifies ZDHHC7 loss as a biomarker for aggressive PCa and a target for therapeutic intervention.

Clinical and Social Outcomes of Cochlear Implantation in Older Prelinguals.

BACKGROUND AND OBJECTIVES: Cochlear implantation in late implanted prelinguals necessitates a complex decision-making process for clinicians and patients due to the uncertainty of achieving adequate benefit in auditory and speech perception. This study longitudinally evaluated clinical and social outcomes of prelingually deaf children with implantation in their late childhood. Subjects and. METHODS: A total of 113 (49 females and 64 males) participants, with an age range of 5-15 years, were assessed for the pre-implant parameters such as hearing loss etiology, aided responses, anatomical aspects, and psychological evaluation. The Category of Auditory Performance, Speech Awareness Threshold, Speech Reception Threshold, and Speech Discrimination Score were administered to assess the patient's auditory skills. Further, the Speech Intelligibility Rating scale was administered to evaluate the patient's speech intelligibility at 3, 6, 9, 12, 18, and 24 months post-surgery. Subjectively perceived benefits were evaluated using the satisfaction rating scale and a questionnaire. RESULTS: The statistical results showed a significant impact of cochlear implantation in all domains. Positive impact and improvement post-implantation were noted in all the spheres, including auditory, linguistic, social, and educational. CONCLUSIONS: The study highlighted that the outcomes of a cochlear implant at a later age might not parallel with the implantation at a younger age. However, this still provides measurable benefits even after a longer period of auditory deprivation.

Hydrophobically Modified Abelmoschus esculentus Polysaccharide Based Nanoparticles and Applications: A Review.

Nanomaterials are indeed a nanoscale technology that deals with the creation, evaluation, fabrication, and utilization of systems at the nanometre scale by manipulating their size and shape. We consider natural polysaccharides such as promising polysaccharides, which are biodegradable, nontoxic, abundant, and inexpensive bio-polymeric precursors for preparing the materials of choice in various industries. The aim is to review different methods to produce hydrophobically modified Abelmoschus esculentus nanoparticles and study the evaluation processes of these nanoparticles as given in the literature. It proved the benefits of derivatives of gum by introducing different chemical groups. The chemical functionalization of gum mainly includes the esterification, etherification, and crosslinking reactions of the hydroxyl groups and contains a special fibre which takes sugar levels in the blood under control, providing a sugar quantity suitable for the bowels. Okra contains mucilage that helps remove poisonous chemicals and bad cholesterol, often overloads the liver. Recovering from psychological conditions, like depression, general weakness, and joint healthiness can be done with Okra. Someone additionally applied it for pulmonary inflammation, bowel irritation, and sore throat. Purgative properties okra possesses are beneficial for bowel purification. It is used to counteract the acids. Fibre okra contains a valuable nutrient for intestinal microorganisms and ensures proper intestine functionality. It also protects the mucosa of the digestive tract by covering them with an extra layer because of its alkaline nature. Nanotechnology has emerged as a critical component of pharmaceutics, with many applications in drug carriers of interest aimed at improving drug clinical outcomes such as cancer, diabetes mellitus, wound care management, atopic dermatitis, cosmeceutical, etc. Beneficial outcomes of this review are discussed briefly.

Association of Hematologic biomarkers and their combinations with disease severity and mortality in COVID-19- an Indian perspective.

BACKGROUND: COVID-19 is a systemic viral infection with a significant impact on the hematopoietic system, hemostasis as well as immune system. It would be of utmost importance to explore if the most routinely used tests could serve as an aid in determining patient's clinical status or predicting severity of the disease. METHODS: A prospective cross-sectional study was conducted on 506 Covid-19 positive patients and 200 controls over a period of two months (June and July 2020). The cases were sub-classified based on disease severity into mild to moderate (n=337), severe (n=118) and very severe (n=51) and based on survivor status into survivors (n=473) and non-survivors (n=33). RESULTS: There were statistically significant differences in WBC count, Absolute neutrophil count (ANC), Absolute lymphocyte count (ALC), absolute monocyte count (AMC), neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR) Red blood cell distribution width (RDW-SD) and RDW CV between covid cases vs controls; among the clinical subgroups and among the survivors and non-survivors. There was a significant strong positive correlation between various parameters, that is, NLR and MLR (r: 0.852, P=0), MPV and PDW (r: 0.912, P=0), MPV and PLCR (r: 0.956, P=0), PDW and PLCR (r: 0.893, P=0). NLR (AUC: 0.676, P=0) was the best single parameter and NLR+RDW-CV was best combination parameter as per area under curve (0.871) of ROC to distinguish severe from mild to moderate disease. CONCLUSIONS: Leucocytosis, neutrophilia, lymphopenia and monocytosis were characteristic findings in covid cases while NLR and NLR+RDW-CV emerged as the most effective single and combination CBC parameters in distinguishing mild to moderate and severe cases respectively.

Sexual dimorphism in atrophic effects of topical glucocorticoids is driven by differential regulation of atrophogene REDD1 in male and female skin.

Topical glucocorticoids, well-known anti-inflammatory drugs, induce multiple adverse effects, including skin atrophy. The sex-specific effects of systemic glucocorticoids are known, but sexual dimorphism of therapeutic and side effects of topical steroids has not been studied. We report here that female and male mice were equally sensitive to the anti-inflammatory effect of glucocorticoid fluocinolone acetonide (FA) in ear edema test. At the same time, females were more sensitive to FA-induced skin atrophy. We recently reported that REDD1 (regulated in development and DNA damage 1) plays central role in steroid atrophy. We found that REDD1 was more efficiently activated by FA in females, and that REDD1 knockout significantly protected female but not male mice from skin atrophy. Studies using human keratinocytes revealed that both estradiol and FA induced REDD1 mRNA/protein expression, and cooperated when they were combined at low doses. Chromatin immunoprecipitation analysis confirmed that REDD1 is an estrogen receptor (ER) target gene with multiple estrogen response elements in its promoter. Moreover, experiments with GR and ER inhibitors suggested that REDD1 induction by these hormones was interdependent on functional activity of both receptors. Overall, our results are important for the development of safer GR-targeted therapies suited for female and male dermatological patients.

PI3K inhibitors protect against glucocorticoid-induced skin atrophy.

BACKGROUND: Skin atrophy is a major adverse effect of topical glucocorticoids. We recently reported that REDD1 (regulated in development and DNA damage 1) and FKBP51 (FK506 binding protein 5), negative regulators of mTOR/Akt signaling, are induced by glucocorticoids in mouse and human skin and are central drivers of steroid skin atrophy. Thus, we hypothesized that REDD1/FKBP51 inhibitors could protect skin against catabolic effects of glucocorticoids. METHODS: Using drug repurposing approach, we screened LINCS library (http://lincsproject.org/LINCS/) to identify repressors of REDD1/FKBP51 expression. Candidate compounds were tested for their ability to inhibit glucocorticoid-induced REDD1/FKBP51 expression in human primary/immortalized keratinocytes and in mouse skin. Reporter gene expression, microarray, and chromatin immunoprecipitation were employed to evaluate effect of these inhibitors on the glucocorticoid receptor (GR) signaling. FINDINGS: Bioinformatics analysis unexpectedly identified phosphoinositide-3-kinase (PI3K)/mTOR/Akt inhibitors as a pharmacological class of REDD1/FKBP51 repressors. Selected PI3K/mTOR/Akt inhibitors-Wortmannin (WM), LY294002, AZD8055, and two others indeed blocked REDD1/FKBP51expression in human keratinocytes. PI3K/mTOR/Akt inhibitors also modified global effect of glucocorticoids on trascriptome, shifting it towards therapeutically important transrepression; negatively impacted GR phosphorylation; nuclear translocation; and GR loading on REDD1/FKBP51 gene promoters. Further, topical application of LY294002 together with glucocorticoid fluocinolone acetonide (FA) protected mice against FA-induced proliferative block and skin atrophy but did not alter the anti-inflammatory activity of FA in ear edema test. INTERPRETATION: Our results built a strong foundation for development of safer GR-targeted therapies for inflammatory skin diseases using combination of glucocorticoids with PI3K/mTOR/Akt inhibitors. FUND: Work is supported by NIH grants R01GM112945, R01AI125366, and HESI-THRIVE foundation.

Type 1 diabetes in older adults: Comparing treatments and chronic complications in the United States T1D Exchange and the German/Austrian DPV registries.

AIMS: Compare characteristics, therapies and clinical outcomes in older adults with type 1 diabetes in the United States T1D Exchange (T1DX) and German/Austrian Diabetes Patienten Verlaufsdokumentation (DPV) registries. METHODS: Cross-sectional study of adults ≥60years old with type 1 diabetes seen in 2011-2012 in the T1DX (n=1283) and DPV (n=2014) registries. Wilcoxon rank-sum test was used for continuous variables and chi-square test for categorical variables. Adjusted analyses used generalized linear models. RESULTS: Individuals in both registries were similar in body mass index (mean 27kg/m2), percent with obesity (25%) and gender (48% male). In T1DX there was longer diabetes duration (32.3 vs. 28.8years), greater use of antihypertensive medications (including ACE-I and ARBs; 85% vs. 62%), statins (68% vs. 40%), aspirin (77% vs. 21%), insulin pumps (58% vs. 18%), and less smoking (7% vs. 10%); lower adjusted mean LDL-cholesterol (84 vs. 109mg/dL), and lower adjusted mean systolic and diastolic blood pressures (128 vs. 136 and 68 vs. 74mmHg); fewer myocardial infarctions (6% vs. 9% [99% CI of difference, 1% to 5%]), strokes (2% vs. 8% [3% to 7%]), microvascular complications including microalbuminuria (17% vs. 44% [22% to 32%]) but increased depression (16.1% vs. 8.7%). Adjusted mean HbA1c levels were similar (7.5%, 58mmol/mol). CONCLUSIONS: Differences between the registries included greater use of antihypertensives, statins and insulin pumps, and fewer chronic complications in the T1DX. Further research is needed to better understand the role of intensive therapy in improving outcomes in older adults with type 1 diabetes.

Cochlear re-implantation: lessons learnt and the way ahead.

Conclusion A cochlear re-implantation procedure is undesirable; however, the cochlear implant surgeon may have to perform a re-implantation procedure occasionally for various reasons. Following standard techniques, implant performance comparable with primary implantation may be achieved. Objective To study the causes and outcomes of cochlear re-implantation in an Asian Indian population. Study design Retrospective analysis of clinical charts over an 18-year period with prospective follow-up of patients. Methods The charts of 534 patients, who underwent cochlear implant, at an Otorhinolaryngology institutional Centre, from January 1997 to January 2015 were studied. Of these, the charts of 18 patients who underwent cochlear re-implantation were studied. The causes and audiological and speech outcomes were analysed. Results Eighteen patients (3.4%) underwent cochlear re-implantation for various reasons. The commonest indication was device failure in seven patients (39%), followed by electrode extrusion in five (28%), trauma in three (11%), electrode migration in two (11%) and improper electrode placement in one (6%) patient. The audiological performance tests and speech tests either remained the same or improved from those achieved for patients undergoing primary implantation, in 87% patients.

Autophagy and endosomal trafficking inhibition by Vibrio cholerae MARTX toxin phosphatidylinositol-3-phosphate-specific phospholipase A1 activity.

Vibrio cholerae, responsible for acute gastroenteritis secretes a large multifunctional-autoprocessing repeat-in-toxin (MARTX) toxin linked to evasion of host immune system, facilitating colonization of small intestine. Unlike other effector domains of the multifunctional toxin that target cytoskeleton, the function of alpha-beta hydrolase (ABH) remained elusive. This study demonstrates that ABH is an esterase/lipase with catalytic Ser-His-Asp triad. ABH binds with high affinity to phosphatidylinositol-3-phosphate (PtdIns3P) and cleaves the fatty acid in PtdIns3P at the sn1 position in vitro making it the first PtdIns3P-specific phospholipase A1 (PLA1). Expression of ABH in vivo reduces intracellular PtdIns3P levels and its PtdIns3P-specific PLA1 activity blocks endosomal and autophagic pathways. In accordance with recent studies acknowledging the potential of extracellular pathogens to evade or exploit autophagy to prevent their clearance and facilitate survival, this is the first report highlighting the role of ABH in inhibiting autophagy and endosomal trafficking induced by extracellular V. cholerae.

The Streptococcus pyogenes orphan protein tyrosine phosphatase, SP-PTP, possesses dual specificity and essential virulence regulatory functions.

Group A Streptococcus (GAS) is a human pathogen that causes high morbidity and mortality. GAS lacks a gene encoding tyrosine kinase but contains one encoding tyrosine phosphatase (SP-PTP). Thus, GAS is thought to lack tyrosine phosphorylation, and the physiological significance of SP-PTP is, therefore, questionable. Here, we demonstrate that SP-PTP possesses dual phosphatase specificity for Tyr- and Ser/Thr-phosphorylated GAS proteins, such as Ser/Thr kinase (SP-STK) and the SP-STK-phosphorylated CovR and WalR proteins. Phenotypic analysis of GAS mutants lacking SP-PTP revealed that the phosphatase activity per se positively regulates growth, cell division and the ability to adhere to and invade host cells. Furthermore, A549 human lung cells infected with GAS mutants lacking SP-PTP displayed increased Ser-/Thr-/Tyr-phosphorylation. SP-PTP also differentially regulates the expression of ∼50% of the total GAS genes, including several virulence genes potentially through the two-component regulators, CovR, WalR and PTS/HPr regulation of Mga. Although these mutants exhibit attenuated virulence, a GAS mutant overexpressing SP-PTP is hypervirulent. Our study provides the first definitive evidence for the presence and importance of Tyr-phosphorylation in GAS and the relevance of SP-PTP as an important therapeutic target.

Induced autoprocessing of the cytopathic Makes caterpillars floppy-like effector domain of the Vibrio vulnificus†MARTX toxin.

The multifunctional-autoprocessing repeats-in-toxin (MARTX(Vv)) toxin that harbours a varied repertoire of effector domains is the primary virulence factor of Vibrio vulnificus. Although ubiquitously present among Biotype I toxin variants, the 'Makes caterpillars floppy-like' effector domain (MCF(Vv)) is previously unstudied. Using transient expression and protein delivery, MCF(Vv) and MCF(Ah) from the Aeromonas hydrophila MARTX(Ah)) toxin are shown for the first time to induce cell rounding. Alanine mutagenesis across the C-terminal subdomain of MCF(Vv) identified an Arg-Cys-Asp (RCD) tripeptide motif shown to comprise a cysteine protease catalytic site essential for autoprocessing of MCF(Vv). The autoprocessing could be recapitulated in vitro by the addition of host cell lysate to recombinant MCF(Vv), indicating induced autoprocessing by cellular factors. The RCD motif is also essential for cytopathicity, suggesting autoprocessing is essential first to activate the toxin and then to process a cellular target protein resulting in cell rounding. Sequence homology places MCF(Vv) within the C58 cysteine protease family that includes the type III secretion effectors YopT from Yersinia spp. and AvrPphB from Pseudomonas syringae. However, the catalytic site RCD motif is unique compared with other C58 peptidases and is here proposed to represent a new subgroup of autopeptidase found within a number of putative large bacterial toxins.

Mechanisms of inflammasome activation by Vibrio cholerae secreted toxins vary with strain biotype.

Activation of inflammasomes is an important aspect of innate immune responses to bacterial infection. Recent studies have linked Vibrio cholerae secreted toxins to inflammasome activation by using murine macrophages. To increase relevance to human infection, studies of inflammasome-dependent cytokine secretion were conducted with the human THP-1 monocytic cell line and corroborated in primary human peripheral blood mononuclear cells (PBMCs). Both El Tor and classical strains of V. cholerae activated ASC (apoptosis-associated speck-like protein-containing a CARD domain)-dependent release of interleukin-1ß (IL-1ß) when cultured with human THP-1 cells, but the pattern of induction was distinct, depending on the repertoire of toxins the strains produced. El Tor biotype strains induced release of IL-1ß dependent on NOD-like receptor family pyrin domain-containing 3 (NLRP3) and ASC due to the secreted pore-forming toxin hemolysin. Unlike in studies with mouse macrophages, the MARTX toxin did not contribute to IL-1ß release from human monocytic cells. Classical biotype strains, which do not produce either hemolysin or the MARTX toxin, activated low-level IL-1ß release that was induced by cholera toxin (CT) and dependent on ASC but independent of NLRP3 and pyroptosis. El Tor strains likewise showed increased IL-1ß production dependent on CT when the hemolysin gene was deleted. In contrast to studies with murine macrophages, this phenotype was dependent on a catalytically active CT A subunit capable of inducing production of cyclic AMP and not on the B subunit. These studies demonstrate that the induction of the inflammasome in human THP-1 monocytes and in PBMCs by V. cholerae varies with the biotype and is mediated by both NLRP3-dependent and -independent pathways.

Predicting clinical response to anticancer drugs using an ex vivo platform that captures tumour heterogeneity.

Predicting clinical response to anticancer drugs remains a major challenge in cancer treatment. Emerging reports indicate that the tumour microenvironment and heterogeneity can limit the predictive power of current biomarker-guided strategies for chemotherapy. Here we report the engineering of personalized tumour ecosystems that contextually conserve the tumour heterogeneity, and phenocopy the tumour microenvironment using tumour explants maintained in defined tumour grade-matched matrix support and autologous patient serum. The functional response of tumour ecosystems, engineered from 109 patients, to anticancer drugs, together with the corresponding clinical outcomes, is used to train a machine learning algorithm; the learned model is then applied to predict the clinical response in an independent validation group of 55 patients, where we achieve 100% sensitivity in predictions while keeping specificity in a desired high range. The tumour ecosystem and algorithm, together termed the CANScript technology, can emerge as a powerful platform for enabling personalized medicine.

Vibrio cholerae MARTX toxin heterologous translocation of beta-lactamase and roles of individual effector domains on cytoskeleton dynamics.

The Vibrio cholerae MARTXVc toxin delivers three effector domains to eukaryotic cells. To study toxin delivery and function of individual domains, the rtxA gene was modified to encode toxin with an in-frame beta-lactamase (Bla) fusion. The hybrid RtxA::Bla toxin was Type I secreted from bacteria; and then Bla was translocated into eukaryotic cells and delivered by autoprocessing, demonstrating that the MARTXVc toxin is capable of heterologous protein transfer. Strains that produce hybrid RtxA::Bla toxins that carry one effector domain in addition to Bla were found to more efficiently translocate Bla. In cell biological assays, the actin cross-linking domain (ACD) and Rho-inactivation domain (RID) are found to cross-link actin and inactivate RhoA, respectively, when other effector domains are absent, with toxin autoprocessing required for high efficiency. The previously unstudied alpha-beta hydrolase domain (ABH) is shown here to activate CDC42, although the effect is ameliorated when RID is also present. Despite all effector domains acting on cytoskeleton assembly, the ACD was sufficient to rapidly inhibit macrophage phagocytosis. Both the ACD and RID independently disrupted polarized epithelial tight junction integrity. The sufficiency of ACD but strong selection for retention of RID and ABH suggests these two domains may primarily function by modulating cell signaling.

Identification and characterization of a positive regulatory cis-element within the upstream region of c-jun.

Jun oncoprotein, a component of transcription factor AP-1, is responsible for expression of multiple genes which trigger cell proliferation, differentiation and apoptosis. The diverse regulatory roles that c-Jun plays point towards its varied and complex transcriptional regulation under different physiological conditions. This could possibly involve an interplay of different trans-acting factors and multiple cis-acting elements present in the c-jun. It is, therefore, important to identify such regulatory elements that could be involved in its stringent up- or down-regulation. In the present study, transient transfection analysis with stepwise deletion variants of the upstream region (-563 to -273), linked to basal c-jun promoter in a reporter plasmid revealed the existence of multiple regulatory regions that modulated gene expression. Further delineation of the region, conferring positive regulation of transcription from the c-jun promoter, led to the identification of a cis-acting element spanning -538 to -514 region. The trans-acting factor(s) present in rat liver nuclear extract interacted specifically only in the phosphorylated form, and with a high affinity to the recognition sequence. UV cross-linking and South-western blotting, in conjunction with the analysis of affinity purified proteins interacting with this region, revealed that at least two protein factors of approximately 45 kDa and approximately 34 kDa bind specifically to this region.

Spinal motoneuron excitability in iron deficiency anaemia.

Decreased tissue oxygenation resulting from iron deficiency anaemia produces generalized weakness and fatigue. The precise physiological mechanism underlying this weakness is unknown and studies in this regard have been scarce. One possible underlying mechanism has been suggested to be reduction of spinal motoneuron excitability. F waves are low amplitude motor responses to nerve stimulation, produced by antidromic activation of the peripheral motor fibers, resulting in recurrent discharge of motoneurons. F waves have been established as an efficient tool to assess spinal motoneuron excitability. 15 patients of iron deficiency anaemia using inclusion criteria of hemoglobin level < 9 g/dL and serum ferritin < 15 microg/L were studied. 8 controls with hemoglobin levels > 12 g/ dL were also included. Bilateral median and common peroneal F wave studies were performed. F wave mean latency, chronodispersion, persistence and mean amplitude were studied. They were within the normal range and no significant differences between the patients and the controls were found. We conclude that spinal motoneuron excitability is not reduced in iron deficiency anaemia. A decreased tissue oxygenation leading to a change in the brain neurotransmitters may have a role to play.