Baseline data were collected in Cape Town during 2006 to study if patients on combination antiretroviral therapy (ART) experience decreased inhibition to avoid risky sexual behavior. A total of 924 ...HIV-positive individuals were recruited; 520 who initiated ART within 3 months and 404 waiting for ART. Nearly half of men (40.1%) and women (46.3%) reported having unprotected sex their last time. Men and women who did not disclose their HIV status to their partner Odds ration (OR) = 2.57 (95% CI: 1.22–5.50) and 2.84 (95% CI: 1.84–4.39), respectively, and those with ambivalent perception about the relationship between ART and HIV transmission OR = 2.08 (95% CI: 1.00–4.30) and 2.39 (95% CI: 1.50–3.84), respectively, were twice as likely to have had unprotected sex their last time. Results suggest an urgent need to strengthen prevention interventions among HIV-positive individuals on and about to start ART in this setting.
The contribution of inducible nitric oxide synthase
(iNOS) to oxidative/nitrative stress is well-documented in inflammation, but difficult to quantify. Using a novel, recently developed assay for ...3-nitrotyrosine (3-NT), we characterized iNOS activity and its inhibition in preclinical models of inflammation. In particular, we utilized the 3-NT assay to assess the role of iNOS in the disease pathology as well as for proof of pharmacology of iNOS inhibitors in an acute endotoxin challenge model, in models of rheumatoid arthritis (RA) such as rat adjuvant- and collagen-induced arthritis (AIA and CIA) and a model of osteoarthritis (OA) such as rat sodium monoiodoacetate-induced arthritis (MIA). Quantification of nitrotyrosine was performed using immuno-affinity 2-D LC–MS/MS assay. This assay is a very specific and reproducible and is amenable to a number of biological fluids. Plasma levels of 3-NT were significantly elevated in an acute model of inflammation (rat LPS) and in models of rheumatoid arthritis (adjuvant- and collagen-induced arthritis), and osteoarthritis (monoiodoacetate-induced arthritis). Plasma 3-NT correlated with the severity of the inflammatory response; thus, a 20-fold increase was observed in the rat LPS model, a 10-fold increase in AIA, and only a 2.5-fold elevation in CIA. Pharmacological intervention with iNOS inhibitors decreased 3-NT levels and associated pathology. 3-NT determination allowed for better elucidation of the role of iNOS in RA and OA disease patholog
y and provided proof of pharmacology for NOS inhibitors in animal models of RA and OA.
The spectrum of nonalcoholic fatty liver disease (NAFLD) includes steatosis, nonalcoholic steatohepatitis (NASH), and cirrhosis. Recognition and timely diagnosis of these different stages, ...particularly NASH, is important for both potential reversibility and limitation of complications. Liver biopsy remains the clinical standard for definitive diagnosis. Diagnostic tools minimizing the need for invasive procedures or that add information to histologic data are important in novel management strategies for the growing epidemic of NAFLD. We describe an “omics” approach to detecting a reproducible signature of lipid metabolites, aqueous intracellular metabolites, SNPs, and mRNA transcripts in a double-blinded study of patients with different stages of NAFLD that involves profiling liver biopsies, plasma, and urine samples. Using linear discriminant analysis, a panel of 20 plasma metabolites that includes glycerophospholipids, sphingolipids, sterols, and various aqueous small molecular weight components involved in cellular metabolic pathways, can be used to differentiate between NASH and steatosis. This identification of differential biomolecular signatures has the potential to improve clinical diagnosis and facilitate therapeutic intervention of NAFLD.
In the search for bioactive sphingosine 1-phosphate (S1P) receptor ligands, a series of 2-amino-2-heterocyclic-propanols were synthesized. These molecules were discovered to be substrates of ...human-sphingosine kinases 1 and 2 (SPHK1 and SPHK2). When phosphorylated, the resultant phosphates showed varied activities at the five sphingosine-1-phosphate (S1P) receptors (S1P
1–5). Agonism at S1P
1 was displayed in vivo by induction of lymphopenia. A stereochemical preference of the quaternary carbon was crucial for phosphorylation by the kinases and alters binding affinities at the S1P receptors. Oxazole and oxadiazole compounds are superior kinase substrates to FTY720, the prototypical prodrug immunomodulator, fingolimod (FTY720). The oxazole-derived structure was the most active for human SPHK2. Imidazole analogues were less active substrates for SPHKs, but more potent and selective agonists of the S1P
1 receptor; additionally, the imidazole class of compounds rendered mice lymphopenic.
Mutations affecting isocitrate dehydrogenase (IDH) enzymes are prevalent in glioma, leukemia, and other cancers. Although mutant IDH inhibitors are effective against leukemia, they seem to be less ...active in aggressive glioma, underscoring the need for alternative treatment strategies. Through a chemical synthetic lethality screen, we discovered that IDH1-mutant glioma cells are hypersensitive to drugs targeting enzymes in the de novo pyrimidine nucleotide synthesis pathway, including dihydroorotate dehydrogenase (DHODH). We developed a genetically engineered mouse model of mutant IDH1-driven astrocytoma and used it and multiple patient-derived models to show that the brain-penetrant DHODH inhibitor BAY 2402234 displays monotherapy efficacy against IDH-mutant gliomas. Mechanistically, this reflects an obligate dependence of glioma cells on the de novo pyrimidine synthesis pathway and mutant IDH's ability to sensitize to DNA damage upon nucleotide pool imbalance. Our work outlines a tumor-selective, biomarker-guided therapeutic strategy that is poised for clinical translation.
Abstract
Metastasis is a very inefficient process in which few disseminated cancer cells survive. We developed a patient-derived xenograft assay in which melanomas engraft and spontaneously ...metastasize (Quintana Nature 456:593-598). Using this assay, we discovered that melanoma cells experience a spike in reactive oxygen species during metastasis and that distant metastasis is limited by oxidative stress (Piskounova Nature 527:186-191). Successfully metastasizing cells undergo reversible metabolic changes during metastasis that increase oxidative stress resistance. For example, melanoma cells in lymph experience less oxidative stress and form more metastases than melanoma cells in the blood (Ubellacker Nature 585:113-120). This is true in both patient-derived melanomas growing in immunocompromised mice and mouse melanomas growing in syngeneic immunocompetent mice. Cells metastasizing through blood, but not lymph, appear to undergo ferroptosis, a form of cell death marked by lipid oxidation. Multiple differences between lymph fluid and blood plasma may contribute to this difference in oxidative stress, including higher levels of oleic acid in lymph. Oleic acid is a monounsaturated fatty acid that protects melanoma cells from ferroptosis, apparently by reducing the abundance of oxidizable polyunsaturated fatty acids (PUFAs) in phospholipids. In the current study we found that some PUFAs sensitize melanoma cells to lipid peroxidation and cell death more than others. Moreover, we analyzed the lipid profiles of common sites of distant metastasis – liver, brain, kidney, pancreas, bone marrow, lung, and liver – and found that the PUFA compositions of these tissues varies significantly. This raises the possibility that metastasizing melanoma cells may incorporate more PUFAs into their phospholipid membranes and exhibit increased ferroptosis sensitivity in some metastatic sites as compared to others. We found that melanoma cells isolated from metastatic sites by flow cytometry had higher levels of PUFAs in their phospholipid membranes compared to those isolated from subcutaneous tissues. These cells isolated from distal sites also exhibited higher levels of lipid ROS and contained higher levels of oxidized lipid species compared to subcutaneous tumors. These data suggest that the lipid metabolism of metastatic tumors reflects both lipid availability in the metastatic site as well as cell-intrinsic differences in lipid metabolism, both of which contribute to lipid ROS. Both cell-intrinsic and cell-extrinsic lipid metabolism likely influence the ability of melanoma cells to survive in distinct metastatic sites during metastasis.
Citation Format: Thomas P. Mathews, Sarah Muh, Arin B. Aurora, Sean J. Morrison. Differences in melanoma lipid metabolism among distinct metastatic sites abstract. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr PR017.
Systemic mycoses have a high impact on tropical renal-transplant recipients.
Data from 1,476 primary renal-transplant recipients was prospectively recorded from 1986 to 2000 at a single center. ...Cumulative incidence of systemic mycoses, its time of occurrence, risk factors, outcome, and postmortem findings in 30 patients with systemic mycoses were analyzed.
A total of 110 episodes of systemic mycoses occurred in 98 patients. The fungal genera Aspergillus, Cryptococcus, and Candida constituted 61% of pathogens, 45% localizing to the lungs. Cytomegalovirus (CMV) disease caused a 5-fold and chronic liver disease a 2-fold increase in systemic mycoses. Tuberculosis (TB) with or without nocardiosis was a significant coinfection. Cyclosporine (CsA) was associated with nearly a 4-fold risk of systemic mycoses less than 6 months from the time of transplantation as compared with prednisolone+azathioprine (PRED+AZA) therapy. Overall, the probability of survival with systemic mycoses was 73.4%, 60.8%, 39.5%, and 25.6% and was 92.5%, 87.5%, 80.0%, and 75.5% without systemic mycoses at 1, 2, 5, and 10 years, respectively (P<0.0001). An extended Cox model with time-independent and dependent covariates showed greater than 15 times the risk of death among those who develop systemic mycoses. Similarly, Posttransplantation (postTX) TB+/-Nocardiosis, preTX TB, CMV disease, diabetes mellitus, PTDM, chronic liver disease (>40 months), and Pred+AZA immunosuppression (>2 years) had 3.5, 1.5, 2.9, 1.9, 1.4, 1.6, 2.3 times the risk for death, respectively, as compared with those who did not have those risk factors.
There is a recent predominance of Aspergillus among the transplant recipients. The risk factors for systemic mycoses are CMV disease, chronic liver disease, and hyperglycemia, and TB is an important coinfection. Systemic mycoses increased in the early postTX period with CsA. The risk factors for death are systemic mycoses, CMV disease, chronic liver disease (>40 months), diabetes mellitus, and Pred+AZA immunosuppression (>2 years). Overall, the probability of survival with systemic mycoses was poor; however, survival has recently improved.
Exposure of Atlantic croaker (Micropogonias undulatus) to the polychlorinated biphenyl mixture (Aroclor 1254, PCB; 1 mg/kg body wt/day for 30 days) during the early-recrudescence phase of the gonadal ...cycle results in the impairment of LH secretion and gonadal growth. In order to determine whether impairment was due to disruption of the stimulatory GnRH neuroendocrine pathway, we compared various parameters of the GnRH-LH system in early recrudescing vs. spermiating (mature) fish. Seabream GnRH (GnRH) content in the preoptic anterior hypothalamic area (POAH) and pituitary, pituitary GnRH receptor concentrations, and basal and GnRH analog (GnRHa)-induced LH secretion were significantly higher in gonadally mature croaker compared to early-recrudescing fish. In a subsequent experiment, the effects of PCB on the same neuroendocrine indices were investigated during the gonadal recrudescence phase of croaker. PCB exposure during the period of testicular maturation prevented the natural increase in GnRH content in the POAH but not in the pituitary. This finding suggests that PCB may impair GnRH synthesis in the POAH. The number of pituitary GnRH receptors also remained significantly lower in the PCB-exposed group, which was likely due to an impairment of GnRH release. The GnRH content in the POAH, number of pituitary GnRH receptors, and LH secretion in the PCB-exposed group were comparable to those in early-recrudescing fish, suggesting an impairment of normal maturation of the GnRH-LH system during the gonadal recrudescence phase. This impairment may be due to a direct action of PCB on GnRH neurons and/or indirectly via interference with other neurotransmitter pathways that modulate GnRH function.
Quiescent CD4+ T cells restrict human immunodeficiency virus type 1 (HIV-1) infection at early steps of virus replication. Low levels of both deoxyribonucleotide triphosphates (dNTPs) and the ...biosynthetic enzymes required for their de novo synthesis provide one barrier to infection. CD4+ T cell activation induces metabolic reprogramming that reverses this block and facilitates HIV-1 replication. Here, we show that phospholipase D1 (PLD1) links T cell activation signals to increased HIV-1 permissivity by triggering a c-Myc- dependent transcriptional program that coordinates glucose uptake and nucleotide biosynthesis. Decreasing PLD1 activity pharmacologically or by RNA interference diminished c-Myc- dependent expression during T cell activation at the RNA and protein levels. PLD1 inhibition of HIV-1 infection was partially rescued by adding exogenous deoxyribonucleosides that bypass the need for de novo dNTP synthesis. Moreover, the data indicate that low dNTP levels that impact HIV-1 restriction involve decreased synthesis, and not only increased catabolism of these nucleotides. These findings uncover a unique mechanism of action for PLD1 inhibitors and support their further development as part of a therapeutic combination for HIV-1 and other viral infections dependent on host nucleotide biosynthesis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Quiescent CD4+ T cells restrict human immunodeficiency virus type 1 (HIV-1) infection at early steps of virus replication. Low levels of both deoxyribonucleotide triphosphates (dNTPs) and the ...biosynthetic enzymes required for their de novo synthesis provide one barrier to infection. CD4+ T cell activation induces metabolic reprogramming that reverses this block and facilitates HIV-1 replication. Here, we show that phospholipase D1 (PLD1) links T cell activation signals to increased HIV-1 permissivity by triggering a c-Myc-dependent transcriptional program that coordinates glucose uptake and nucleotide biosynthesis. Decreasing PLD1 activity pharmacologically or by RNA interference diminished c-Myc-dependent expression during T cell activation at the RNA and protein levels. PLD1 inhibition of HIV-1 infection was partially rescued by adding exogenous deoxyribonucleosides that bypass the need for de novo dNTP synthesis. Moreover, the data indicate that low dNTP levels that impact HIV-1 restriction involve decreased synthesis, and not only increased catabolism of these nucleotides. These findings uncover a unique mechanism of action for PLD1 inhibitors and support their further development as part of a therapeutic combination for HIV-1 and other viral infections dependent on host nucleotide biosynthesis.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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