Redistribution of cytoplasmic VEGF to the basolateral aspect of renal tubular cells in ischemia-reperfusion injury

Redistribution of cytoplasmic VEGF to the basolateral aspect of renal tubular cells in ischemia-reperfusion injury.BackgroundVascular endothelial growth factor (VEGF) mRNA and protein expression are increased by hypoxia in a variety of cell types and organs. In the kidney, however, chronic hypoxia does not up-regulate VEGF mRNA. This suggests that VEGF may be regulated by unique mechanisms in the kidney.MethodsUnilateral ischemia was induced in rats by vascular cross-clamping (40 min) followed by reperfusion (0, 20, 40, and 80 min). The distribution of VEGF protein was determined by immunohistochemical staining and Western blotting. mRNA was detected by Northern blotting and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). Immunohistochemical staining for VEGF was verified using two VEGF antibodies. To further substantiate the immunohistochemical findings, laser scanning confocal fluorescence microscopy was used to demonstrate the distribution of VEGF protein in rat renal tubular epithelial cells (NRK52-E) subjected to hypoxia (40 min) and re-oxygenation (0, 5, 20, 40 and 80 min).ResultsNormal kidneys showed diffuse immunohistochemical staining for VEGF in all tubules of the renal cortex and medulla. Following ischemia, staining demonstrated a prominent shift of cytoplasmic VEGF to the basolateral aspect of tubular cells with both VEGF antibodies. The distribution of cytoplasmic VEGF returned to normal following 40 and 80 minutes of reperfusion. Western blots of cytoplasmic samples from ischemic kidneys reperfused for 0 and 20 minutes showed decreased levels of VEGF164 compared with normal (P < 0.01). VEGF164 and VEGF188 levels in the membrane fraction showed no change. Northern blots and semiquantitative RT-PCR showed no significant up-regulation of VEGF mRNA or change in the splice pattern. NRK52-E cells subjected to hypoxia and re-oxygenation for 0 and 5 minutes showed increased staining for VEGF compared with normal, with prominent VEGF staining at the periphery of the cell, similar to the appearance in ischemic kidneys. VEGF staining became more diffuse with further re-oxygenation.ConclusionAlthough synthesis of VEGF mRNA and protein is not increased during ischemia reperfusion injury, pre-existing VEGF in the tubular cell cytoplasm redistributes to the basolateral aspect of the cells. These data suggest that the kidney may have evolved unique patterns of VEGF regulation to cope with acute hypoxia

The antimalarial drug amodiaquine stabilizes p53 through ribosome biogenesis stress, independently of its autophagy-inhibitory activity

Pharmacological inhibition of ribosome biogenesis is a promising avenue for cancer therapy. Herein, we report a novel activity of the FDA-approved antimalarial drug amodiaquine which inhibits rRNA transcription, a rate-limiting step for ribosome biogenesis, in a dose-dependent manner. Amodiaquine triggers degradation of the catalytic subunit of RNA polymerase I (Pol I), with ensuing RPL5/RPL11-dependent stabilization of p53. Pol I shutdown occurs in the absence of DNA damage and without the subsequent ATM-dependent inhibition of rRNA transcription. RNAseq analysis revealed mechanistic similarities of amodiaquine with BMH-21, the first-in-class Pol I inhibitor, and with chloroquine, the antimalarial analog of amodiaquine, with well-established autophagy-inhibitory activity. Interestingly, autophagy inhibition caused by amodiaquine is not involved in the inhibition of rRNA transcription, suggesting two independent anticancer mechanisms. In vitro, amodiaquine is more efficient than chloroquine in restraining the proliferation of human cell lines derived from colorectal carcinomas, a cancer type with predicted susceptibility to ribosome biogenesis stress. Taken together, our data reveal an unsuspected activity of a drug approved and used in the clinics for over 30 years, and provide rationale for repurposing amodiaquine in cancer therapy

Combined metabolome and transcriptome profiling provides new insights into diterpene biosynthesis in S. pomifera glandular trichomes

Background: Salvia diterpenes have been found to have health promoting properties. Among them, carnosic acid and carnosol, tanshinones and sclareol are well known for their cardiovascular, antitumor, antiinflammatory and antioxidant activities. However, many of these compounds are not available at a constant supply and developing biotechnological methods for their production could provide a sustainable alternative. The transcriptome of S. pomifera glandular trichomes was analysed aiming to identify genes that could be used in the engineering of synthetic microbial systems. Results: In the present study, a thorough metabolite analysis of S. pomifera leaves led to the isolation and structure elucidation of carnosic acid-family metabolites including one new natural product. These labdane diterpenes seem to be synthesized through miltiradiene and ferruginol. Transcriptomic analysis of the glandular trichomes from the S. pomifera leaves revealed two genes likely involved in miltiradiene synthesis. Their products were identified and the corresponding enzymes were characterized as copalyl diphosphate synthase (SpCDS) and miltiradiene synthase (SpMilS). In addition, several CYP-encoding transcripts were identified providing a valuable resource for the identification of the biosynthetic mechanism responsible for the production of carnosic acid-family metabolites in S. pomifera. Conclusions: Our work has uncovered the key enzymes involved in miltiradiene biosynthesis in S. pomifera leaf glandular trichomes. The transcriptomic dataset obtained provides a valuable tool for the identification of the CYPs involved in the synthesis of carnosic acid-family metabolites.General Secretariat of Research and Technology (GSRT) {[}09-SYN-23-879]; grant SEE-ERA. NET PLUS {[}ERA 64/01]; grant KRIPIS {[}MIS 448840

Actionable cancer vulnerability due to translational arrest, p53 aggregation and ribosome biogenesis stress evoked by the disulfiram metabolite CuET.

We would like to thank M.Oren (Weizmann Institute of Science) for kindly providing the MDM2 antibodies, the core facility for Bioinformatics and Expression Analysis (BEA, Karolinska, Huddinge) for assisting in massive parallel sequencing and computational infrastructure, as well as E Dratkiewicz, AS Nilsson, and JF Martinez for excellent technical assistance.Drug repurposing is a versatile strategy to improve current therapies. Disulfiram has long been used in the treatment of alcohol dependency and multiple clinical trials to evaluate its clinical value in oncology are ongoing. We have recently reported that the disulfiram metabolite diethyldithiocarbamate, when combined with copper (CuET), targets the NPL4 adapter of the p97VCP segregase to suppress the growth of a spectrum of cancer cell lines and xenograft models in vivo. CuET induces proteotoxic stress and genotoxic effects, however important issues concerning the full range of the CuET-evoked tumor cell phenotypes, their temporal order, and mechanistic basis have remained largely unexplored. Here, we have addressed these outstanding questions and show that in diverse human cancer cell models, CuET causes a very early translational arrest through the integrated stress response (ISR), later followed by features of nucleolar stress. Furthermore, we report that CuET entraps p53 in NPL4-rich aggregates leading to elevated p53 protein and its functional inhibition, consistent with the possibility of CuET-triggered cell death being p53-independent. Our transcriptomics profiling revealed activation of pro-survival adaptive pathways of ribosomal biogenesis (RiBi) and autophagy upon prolonged exposure to CuET, indicating potential feedback responses to CuET treatment. The latter concept was validated here by simultaneous pharmacological inhibition of RiBi and/or autophagy that further enhanced CuET's tumor cytotoxicity, using both cell culture and zebrafish in vivo preclinical models. Overall, these findings expand the mechanistic repertoire of CuET's anti-cancer activity, inform about the temporal order of responses and identify an unorthodox new mechanism of targeting p53. Our results are discussed in light of cancer-associated endogenous stresses as exploitable tumor vulnerabilities and may inspire future clinical applications of CuET in oncology, including combinatorial treatments and focus on potential advantages of using certain validated drug metabolites, rather than old, approved drugs with their, often complex, metabolic profiles.This work was funded by the following grants: the Swedish Cancer Society (grant number: 170176), the Swedish Research Council (VR-MH 2014-46602-117891-30), Novo Nordisk Foundation (NNF20OC0060590), Danish National Research Foundation (project CARD, DNRF 125), the Danish Cancer Society (R204-A12617-B153), DFF 1026-00241B (all granted to JB), and the Grant agency of the Czech Republic: GACR 20-28685S (granted to ZS and MM). Open access funding provided by Karolinska Institute.S

Protective role of vitamin B6 (PLP) against DNA damage in Drosophila models of type 2 diabetes

Growing evidence shows that improper intake of vitamin B6 increases cancer risk and several studies indicate that diabetic patients have a higher risk of developing tumors. We previously demonstrated that in Drosophila the deficiency of Pyridoxal 5' phosphate (PLP), the active form of vitamin B6, causes chromosome aberrations (CABs), one of cancer prerequisites, and increases hemolymph glucose content. Starting from these data we asked if it was possible to provide a link between the aforementioned studies. Thus, we tested the effect of low PLP levels on DNA integrity in diabetic cells. To this aim we generated two Drosophila models of type 2 diabetes, the first by impairing insulin signaling and the second by rearing flies in high sugar diet. We showed that glucose treatment induced CABs in diabetic individuals but not in controls. More interestingly, PLP deficiency caused high frequencies of CABs in both diabetic models demonstrating that hyperglycemia, combined to reduced PLP level, impairs DNA integrity. PLP-depleted diabetic cells accumulated Advanced Glycation End products (AGEs) that largely contribute to CABs as α-lipoic acid, an AGE inhibitor, rescued not only AGEs but also CABs. These data, extrapolated to humans, indicate that low PLP levels, impacting on DNA integrity, may be considered one of the possible links between diabetes and cancer

Sex-Specific Association of the Putative Fructose Transporter SLC2A9 Variants With Uric Acid Levels Is Modified by BMI

OBJECTIVE—High serum uric acid levels lead to gout and have been reported to be associated with an increased risk of hypertension, obesity, metabolic syndrome, type 2 diabetes, and cardiovascular disease. Recently, the putative fructose transporter SLC2A9 was reported to influence uric acid levels. The aim of the present study was to examine the association of four single nucleotide polymorphisms within this gene with uric acid levels and to determine whether this association is modified by obesity

Towards elucidating carnosic acid biosynthesis in Lamiaceae: Functional characterization of the three first steps of the pathway in Salvia fruticosa and Rosmarinus officinalis

Carnosic acid (CA) is a phenolic diterpene with anti-tumour, anti-diabetic, antibacterial and neuroprotective properties that is produced by a number of species from several genera of the Lamiaceae family, including Salvia fruticosa (Cretan sage) and Rosmarinus officinalis (Rosemary). To elucidate CA biosynthesis, glandular trichome transcriptome data of S. fruticosa were mined for terpene synthase genes. Two putative diterpene synthase genes, namely SfCPSand SfKSL, showing similarities to copalyl diphosphate synthase and kaurene synthase-like genes, respectively, were isolated and functionally characterized. Recombinant expression in Escherichia coli followed by in vitro enzyme activity assays confirmed that SfCPS is a copalyl diphosphate synthase. Coupling of SfCPS with SfKSL, both in vitro and in yeast, resulted in the synthesis miltiradiene, as confirmed by 1D and 2D NMR analyses (1H, 13C, DEPT, COSY H-H, HMQC and HMBC). Coupled transient in vivo assays of SfCPS and SfKSL in Nicotiana benthamiana further confirmed production of miltiradiene in planta. To elucidate the subsequent biosynthetic step, RNA-Seq data of S. fruticosa and R. officinalis were searched for cytochrome P450 (CYP) encoding genes potentially involved in the synthesis of the first phenolic compound in the CA pathway, ferruginol. Three candidate genes were selected, SfFS, RoFS1 and RoFS2. Using yeast and N. benthamiana expression systems, all three where confirmed to be coding for ferruginol synthases, thus revealing the enzymatic activities responsible for the first three steps leading to CA in two Lamiaceae genera

Kidney transplant recipient perspectives on telehealth during the COVID-19 pandemic

The COVID-19 pandemic has challenged the delivery of health services. Telehealth allows delivery of care without in-person contacts and minimizes the risk of vial transmission. We aimed to describe the perspectives of kidney transplant recipients on the benefits, challenges, and risks of telehealth. We conducted five online focus groups with 34 kidney transplant recipients who had experienced a telehealth appointment. Transcripts were thematically analyzed. We identified five themes: minimizing burden (convenient and easy, efficiency of appointments, reducing exposure to risk, limiting work disruptions, and alleviating financial burden); attuning to individual context (depending on stability of health, respect patient choice of care, and ensuring a conducive environment); protecting personal connection and trust (requires established rapport with clinicians, hampering honest conversations, diminished attentiveness without incidental interactions, reassurance of follow-up, and missed opportunity to share lived experience); empowerment and readiness (increased responsibility for self-management, confidence in physical assessment, mental preparedness, and forced independence); navigating technical challenges (interrupted communication, new and daunting technologies, and cognizant of patient digital literacy). Telehealth is convenient and minimizes time, financial, and overall treatment burden. Telehealth should ideally be available after the pandemic, be provided by a trusted nephrologist and supported with resources to help patients prepare for appointments.Brooke M Huuskes, Nicole Scholes-Robertson, Chandana Guha, Amanda Baumgart, Germaine Wong, John Kanellis ... et al

Stabilization of Dicentric Translocations through Secondary Rearrangements Mediated by Multiple Mechanisms in S. cerevisiae

The gross chromosomal rearrangements (GCRs) observed in S. cerevisiae mutants with increased rates of accumulating GCRs include predicted dicentric GCRs such as translocations, chromosome fusions and isoduplications. These GCRs resemble the genome rearrangements found as mutations underlying inherited diseases as well as in the karyotypes of many cancers exhibiting ongoing genome instabilityThe structures of predicted dicentric GCRs were analyzed using multiple strategies including array-comparative genomic hybridization, pulse field gel electrophoresis, PCR amplification of predicted breakpoints and sequencing. The dicentric GCRs were found to be unstable and to have undergone secondary rearrangements to produce stable monocentric GCRs. The types of secondary rearrangements observed included: non-homologous end joining (NHEJ)-dependent intramolecular deletion of centromeres; chromosome breakage followed by NHEJ-mediated circularization or broken-end fusion to another chromosome telomere; and homologous recombination (HR)-dependent non-reciprocal translocations apparently mediated by break-induced replication. A number of these GCRs appeared to have undergone multiple bridge-fusion-breakage cycles. We also observed examples of chromosomes with extensive ongoing end decay in mec1 tlc1 mutants, suggesting that Mec1 protects chromosome ends from degradation and contributes to telomere maintenance by HR.HR between repeated sequences resulting in secondary rearrangements was the most prevalent pathway for resolution of dicentric GCRs regardless of the structure of the initial dicentric GCR, although at least three other resolution mechanisms were observed. The resolution of dicentric GCRs to stable rearranged chromosomes could in part account for the complex karyotypes seen in some cancers