ER-mitochondria contacts and cholesterol metabolism are disrupted by disease-associated tau protein.

Abnormal tau protein impairs mitochondrial function, including transport, dynamics, and bioenergetics. Mitochondria interact with the endoplasmic reticulum (ER) via mitochondria-associated ER membranes (MAMs), which coordinate and modulate many cellular functions, including mitochondrial cholesterol metabolism. Here, we show that abnormal tau loosens the association between the ER and mitochondria in vivo and in vitro. Especially, ER-mitochondria interactions via vesicle-associated membrane protein-associated protein (VAPB)-protein tyrosine phosphatase-interacting protein 51 (PTPIP51) are decreased in the presence of abnormal tau. Disruption of MAMs in cells with abnormal tau alters the levels of mitochondrial cholesterol and pregnenolone, indicating that conversion of cholesterol into pregnenolone is impaired. Opposite effects are observed in the absence of tau. Besides, targeted metabolomics reveals overall alterations in cholesterol-related metabolites by tau. The inhibition of GSK3ß decreases abnormal tau hyperphosphorylation and increases VAPB-PTPIP51 interactions, restoring mitochondrial cholesterol and pregnenolone levels. This study is the first to highlight a link between tau-induced impairments in the ER-mitochondria interaction and cholesterol metabolism.

Metabolic outcomes in obese mice undergoing one-anastomosis gastric bypass (OAGB) with a long or a short biliopancreatic limb.

One-anastomosis gastric bypass (OAGB) has gained importance as a simple, safe, and effective operation to treat morbid obesity. We previously found that Roux-en-Y gastric bypass surgery with a long compared with a short biliopancreatic limb (BPL) leads to improved weight loss and glucose tolerance in obese mice. However, it is not known whether a long BPL in OAGB surgery also results in beneficial metabolic outcomes. Five-week-old male C57BL/6J mice fed a high-fat diet (HFD) for 8 weeks underwent OAGB surgery with defined BPL lengths (5.5 cm distally of the duodenojejunal junction for short and 9.5 cm for long BPL), or sham surgery combined with caloric restriction. Weight loss, glucose tolerance, obesity-related comorbidities, endocrine effects, gut microbiota, and bile acids were assessed. Total weight loss was independent of the length of the BPL after OAGB surgery. However, a long BPL was associated with lower glucose-stimulated insulin on day 14, and an improved glucose tolerance on day 35 after surgery. Moreover, a long BPL resulted in reduced total cholesterol, while there were no differences in the resolution of metabolic dysfunction-associated steatotic liver disease (MASLD) and adipose tissue inflammation. Tendencies of an attenuated hypothalamic-pituitary-adrenal (HPA) axis and aldosterone were present in the long BPL group. With both the short and long BPL, we found an increase in primary conjugated bile acids (pronounced in long BPL) along with a loss in bacterial Desulfovibrionaceae and Erysipelotrichaceae and simultaneous increase in Akkermansiaceae, Sutterellaceae, and Enterobacteriaceae. In summary, OAGB surgery with a long compared with a short BPL led to similar weight loss, but improved glucose metabolism, lipid, and endocrine outcomes in obese mice, potentially mediated through changes in gut microbiota and related bile acids. Tailoring the BPL length in humans might help to optimize metabolic outcomes after bariatric surgery.NEW & NOTEWORTHY Weight loss following OAGB surgery in obese mice was not influenced by BPL length, but a longer BPL was associated with improved metabolic outcomes, including glucose and lipid homeostasis. These changes could be mediated by bile acids upon altered gut microbiota. Further validation of these findings is required through a randomized human study.

In silico and in vitro assessment of drugs potentially causing adverse effects by inhibiting CYP17A1.

Cytochrome P450 enzymes (CYPs) play a crucial role in the metabolism and synthesis of various compound classes. While drug-metabolizing CYP enzymes are frequently investigated as anti-targets, the inhibition of CYP enzymes involved in adrenal steroidogenesis is not well studied. The steroidogenic enzyme CYP17A1 is a dual-function enzyme catalyzing hydroxylase and lyase reactions relevant for the biosynthesis of adrenal glucocorticoids and androgens. Inhibition of CYP17A1-hydroxylase leads to pseudohyperaldosteronism with subsequent excessive mineralocorticoid receptor activation, hypertension and hypokalemia. In contrast, specific inhibition of the lyase function might be beneficial for the treatment of prostate cancer by decreasing adrenal androgen levels. This study combined in silico and in vitro methods to identify drugs inhibiting CYP17A1. The most potent CYP17A1 inhibitors identified are serdemetan, mocetinostat, nolatrexed, liarozole, and talarozole. While some of these drugs are currently under investigation for the treatment of various cancers, their potential for the treatment of prostate cancer is yet to be explored. The DrugBank database was screened for CYP17A1 inhibitors, to increase the awareness for the risk of drug-induced pseudohyperaldosteronism and to highlight drugs so far unknown for their potential to cause side effects resulting from CYP17A1 inhibition.

Patients with naproxen-induced liver injury display T-cell memory responses toward an oxidative (S)-O-desmethyl naproxen metabolite but not the acyl glucuronide.

BACKGROUND: Exposure to nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen (IBU) and naproxen (NAP) is associated with idiosyncratic drug-induced liver injury (DILI). Carboxylate bioactivation into reactive metabolites (e.g., acyl glucuronides, AG) and resulting T-cell activation is hypothesized as causal for this adverse event. However, conclusive evidence supporting this is lacking. METHODS: In this work, we identify CD4+ and CD8+ T-cell hepatic infiltration in a biopsy from an IBU DILI patient. Lymphocyte transformation test and IFN-γ ELIspot, conducted on peripheral blood mononuclear cells (PBMCs) of patients with NAP-DILI, were used to explore drug-specific T-cell activation. T-cell clones (TCC) were generated and tested for drug specificity, phenotype/function, and pathways of T-cell activation. Cells were exposed to NAP, its oxidative metabolite 6-O-desmethyl NAP (DM-NAP), its AG or synthesized NAP-AG human-serum albumin adducts (NAP-AG adduct). RESULTS: CD4+ and CD8+ T-cells from patients expressing a range of different Vß receptors were stimulated to proliferate and secrete IFN-γ and IL-22 when exposed to DM-NAP, but not NAP, NAP-AG or the NAP-AG adduct. Activation of the CD4+ TCC was HLA-DQ-restricted and dependent on antigen presenting cells (APC); most TCC were activated with DM-NAP-pulsed APC, while fixation of APC blocked the T-cell response. Cross-reactivity was not observed with structurally-related drugs. CONCLUSION: Our results confirm hepatic T-cell infiltrations in NSAID-induced DILI, and show a T-cell memory response toward DM-NAP indicating an immune-mediated basis for the adverse event. Whilst bioactivation at the carboxylate group is widely hypothesized to be pathogenic for NSAID associated DILI, we found no evidence of this with NAP.

A novel mouse model for an inducible gene modification in the renal thick ascending limb.

The thick ascending limb (TAL) is critical for renal control of fluid and ion homeostasis. The function of the TAL depends on the activity of the bumetanide-sensitive Na+-K+-2Cl- cotransporter (NKCC2), which is highly abundant in the luminal membrane of TAL cells. TAL function is regulated by various hormonal and nonhormonal factors. However, many of the underlying signal transduction pathways remain elusive. Here, we describe and characterize a novel gene-modified mouse model for an inducible and specific Cre/Lox-mediated gene modification in the TAL. In these mice, tamoxifen-dependent Cre (CreERT2) was inserted into the 3'-untranslated region of the Slc12a1 gene, which encodes NKCC2 (Slc12a1-CreERT2). Although this gene modification strategy slightly reduced endogenous NKCC2 expression at the mRNA and protein levels, the lowered NKCC2 abundance was not associated with altered urinary fluid and ion excretion, urinary concentration, and the renal response to loop diuretics. Immunohistochemistry on kidneys from Slc12a1-CreERT2 mice revealed strong Cre expression exclusively in TAL cells but not in any other nephron portion. Cross-breeding of these mice with the mT/mG reporter mouse line showed a very low recombination rate (∼0% in male mice and <3% in female mice) at baseline but complete (∼100%) recombination after repeated tamoxifen administration in male and female mice. The achieved recombination encompassed the entire TAL and also included the macula densa. Thus, the new Slc12a1-CreERT2 mouse line allows inducible and very efficient gene targeting in the TAL and hence promises to be a powerful tool to advance our understanding of the regulation of TAL function.NEW & NOTEWORTHY The renal thick ascending limb (TAL) is critical for renal control of fluid and ion homeostasis. However, the underlying molecular mechanisms that regulate TAL function are incompletely understood. This study describes a novel transgenic mouse model (Slc12a1-creERT2) for inducible and highly efficient gene targeting in the TAL that promises to ease physiological studies on the functional role of candidate regulatory genes.

Virtual screening and biological evaluation to identify pharmaceuticals potentially causing hypertension and hypokalemia by inhibiting steroid 11ß-hydroxylase.

Several drugs were found after their market approval to unexpectedly inhibit adrenal 11ß-hydroxylase (CYP11B1)-dependent cortisol synthesis. Known side-effects of CYP11B1 inhibition include hypertension and hypokalemia, due to a feedback activation of adrenal steroidogenesis, leading to supraphysiological concentrations of 11-deoxycortisol and 11-deoxycorticosterone that can activate the mineralocorticoid receptor. This results in potassium excretion and sodium and water retention, ultimately causing hypertension. With the risk known but usually not addressed in preclinical evaluation, this study aimed to identify drugs and drug candidates inhibiting CYP11B1. Two conceptually different virtual screening methods were combined, a pharmacophore based and an induced fit docking approach. Cell-free and cell-based CYP11B1 activity measurements revealed several inhibitors with IC50 values in the nanomolar range. Inhibitors include retinoic acid metabolism blocking agents (RAMBAs), azole antifungals, α2-adrenoceptor ligands, and a farnesyltransferase inhibitor. The active compounds share a nitrogen atom embedded in an aromatic ring system. Structure activity analysis identified the free electron pair of the nitrogen atom as a prerequisite for the drug-enzyme interaction, with its pKa value as an indicator of inhibitory potency. Another important parameter is drug lipophilicity, exemplified by etomidate. Changing its ethyl ester moiety to a more hydrophilic carboxylic acid group dramatically decreased the inhibitory potential, most likely due to less efficient cellular uptake. The presented work successfully combined different in silico and in vitro methods to identify several previously unknown CYP11B1 inhibitors. This workflow facilitates the identification of compounds that inhibit CYP11B1 and therefore pose a risk for inducing hypertension and hypokalemia.

Nephrotoxicity of iopamidol is associated with mitochondrial impairment in human cell and teleost models.

Iopamidol is a nonionic, low-osmolar iodinated contrast agent used for angiography. Its clinical use is associated with renal dysfunction. Patients suffering from preexisting kidney disease have an increased risk of renal failure upon iopamidol administration. Studies in animals confirmed renal toxicity, but the involved mechanisms remain unclear. Therefore, the aim of the present study was to use human embryonic kidney cells (HEK293T) as a general cell model of mitochondrial damage, as well as, zebrafish larvae, and isolated proximal tubules of killifish to investigate factors promoting renal tubular toxicity of iopamidol with a focus on mitochondrial damage. Results from in vitro HEK293T cell-based assays indicate that iopamidol affects mitochondrial function Treatment with iopamidol induces ATP depletion, reduces the mitochondrial membrane potential, and elevates mitochondrial superoxide and reactive oxygen species accumulation. Similar results were obtained with gentamicin sulfate and cadmium chloride, two well-known model compounds associated with renal tubular toxicity. Confocal microscopy confirms changes in mitochondrial morphology, such as mitochondrial fission. Importantly, these results were confirmed in proximal renal tubular epithelial cells using ex vivo and in vivo teleost models. In conclusion, this study provides evidence for iopamidol-induced mitochondrial damage in proximal renal epithelial cells. Teleost models allow studying proximal tubular toxicity with translational relevance for humans.

Systematic evidence on migrating and extractable food contact chemicals: Most chemicals detected in food contact materials are not listed for use.

Food packaging is important for today's globalized food system, but food contact materials (FCMs) can also be a source of hazardous chemicals migrating into foodstuffs. Assessing the impacts of FCMs on human health requires a comprehensive identification of the chemicals they contain, the food contact chemicals (FCCs). We systematically compiled the "database on migrating and extractable food contact chemicals" (FCCmigex) using information from 1210 studies. We found that to date 2881 FCCs have been detected, in a total of six FCM groups (Plastics, Paper & Board, Metal, Multi-materials, Glass & Ceramic, and Other FCMs). 65% of these detected FCCs were previously not known to be used in FCMs. Conversely, of the more than 12'000 FCCs known to be used, only 1013 are included in the FCCmigex database. Plastic is the most studied FCM with 1975 FCCs detected. Our findings expand the universe of known FCCs to 14,153 chemicals. This knowledge contributes to developing non-hazardous FCMs that lead to safer food and support a circular economy.

Migration Modeling as a Valuable Tool for Exposure Assessment and Risk Characterization of Polyethylene Terephthalate Oligomers.

Polyethylene terephthalate (PET) is one of the most widely used food contact materials due to its excellent mechanical properties and recyclability. Migration of substances from PET and assessment of compliance are usually determined by experimental testing, which can be challenging depending on the migrants of interest. Low concentrations and missing reference standards, among other factors, have led to inadequate investigation of the migration potential of PET oligomers. Migration modeling can overcome such limitations and is therefore a suitable starting point for exposure and risk assessment. In this study, the activation energy-based (EA) model and the AP model were used to systematically evaluate the migration potential of 52 PET oligomers for 12 different application scenarios. Modeling parameters and conditions were evaluated to investigate their impact and relevance on the assessment of realistic exposures. Obtained results were compared with safety thresholds known from the concept of toxicological thresholds of concern. This allowed the evaluation and identification of oligomers and/or applications where migration or exposure levels may be associated with a potential risk because they exceed these safety thresholds. Overall, this study demonstrated that migration modeling can be a high-throughput, fast, flexible, and suitable approach for comprehensive exposure assessment.

Deletion of the transcription factor Prox-1 specifically in the renal distal convoluted tubule causes hypomagnesemia via reduced expression of TRPM6 and NCC.

The renal distal convoluted tubule (DCT) is critical for the fine-tuning of urinary ion excretion and the control of blood pressure. Ion transport along the DCT is tightly controlled by posttranscriptional mechanisms including a complex interplay of kinases, phosphatases, and ubiquitin ligases. Previous work identified the transcription factor Prox-1 as a gene significantly enriched in the DCT of adult mice. To test if Prox-1 contributes to the transcriptional regulation of DCT function and structure, we developed a novel mouse model (NCCcre:Prox-1flox/flox) for an inducible deletion of Prox-1 specifically in the DCT. The deletion of Prox-1 had no obvious impact on DCT structure and growth independent whether the deletion was achieved in newborn or adult mice. Furthermore, DCT-specific Prox-1 deficiency did not alter DCT-proliferation in response to loop diuretic treatment. Likewise, the DCT-specific deletion of Prox-1 did not cause other gross phenotypic abnormalities. Body weight, urinary volume, Na+ and K+ excretion as well as plasma Na+, K+, and aldosterone levels were similar in Prox-1DCTKO and Prox-1DCTCtrl mice. However, Prox-1DCTKO mice exhibited a significant hypomagnesemia with a profound downregulation of the DCT-specific apical Mg2+ channel TRPM6 and the NaCl cotransporter (NCC) at both mRNA and protein levels. The expression of other proteins involved in distal tubule Mg2+ and Na+ handling was not affected. Thus, Prox-1 is a DCT-enriched transcription factor that does not control DCT growth but contributes to the molecular control of DCT-dependent Mg2+ homeostasis in the adult kidney.

Specific disruption of calcineurin-signaling in the distal convoluted tubule impacts the transcriptome and proteome, and causes hypomagnesemia and metabolic acidosis.

Adverse effects of calcineurin inhibitors (CNI), such as hypertension, hyperkalemia, acidosis, hypomagnesemia and hypercalciuria, have been linked to dysfunction of the distal convoluted tubule (DCT). To test this, we generated a mouse model with an inducible DCT-specific deletion of the calcineurin regulatory subunit B alpha (CnB1-KO). Three weeks after CnB1 deletion, these mice exhibited hypomagnesemia and acidosis, but no hypertension, hyperkalemia or hypercalciuria. Consistent with the hypomagnesemia, CnB1-KO mice showed a downregulation of proteins implicated in DCT magnesium transport, including TRPM6, CNNM2, SLC41A3 and parvalbumin but expression of calcium channel TRPV5 in the kidney was unchanged. The abundance of the chloride/bicarbonate exchanger pendrin was increased, likely explaining the acidosis. Plasma aldosterone levels, kidney renin expression, abundance of phosphorylated sodium chloride-cotransporter and abundance of the epithelial sodium channel were similar in control and CnB1-KO mice, consistent with a normal sodium balance. Long-term potassium homeostasis was maintained in CnB1-KO mice, but in-vivo and ex-vivo experiments indicated that CnB1 contributes to acute regulation of potassium balance and sodium chloride-cotransporter. Tacrolimus treatment of control and CnB1-KO mice demonstrated that CNI-related hypomagnesemia is linked to impaired calcineurin-signaling in DCT, while hypocalciuria and hyponatremia occur independently of CnB1 in DCT. Transcriptome and proteome analyses of isolated DCTs demonstrated that CnB1 deletion impacts the expression of several DCT-specific proteins and signaling pathways. Thus, our data support a critical role of calcineurin for DCT function and provide novel insights into the pathophysiology of CNI side effects and involved molecular players in the DCT.

Species-specific differences in the inhibition of 11ß-hydroxysteroid dehydrogenase 2 by itraconazole and posaconazole.

11ß-hydroxysteroid dehydrogenase 2 (11ß-HSD2) converts active 11ß-hydroxyglucocorticoids to their inactive 11-keto forms, thereby preventing inappropriate mineralocorticoid receptor activation by glucocorticoids. Disruption of 11ß-HSD2 activity by genetic defects or inhibitors causes the syndrome of apparent mineralocorticoid excess (AME), characterized by hypokalemia, hypernatremia and hypertension. Recently, the azole antifungals itraconazole and posaconazole were identified to potently inhibit human 11ß-HSD2, and several case studies described patients with acquired AME. To begin to understand why this adverse drug effect was missed during preclinical investigations, the inhibitory potential of itraconazole, its main metabolite hydroxyitraconazole (OHI) and posaconazole against 11ß-HSD2 from human and three commonly used experimental animals was assessed. Whilst human 11ß-HSD2 was potently inhibited by all three compounds (IC50 values in the nanomolar range), the rat enzyme was moderately inhibited (1.5- to 6-fold higher IC50 values compared to human), and mouse and zebrafish 11ß-HSD2 were very weakly inhibited (IC50 values above 7 µM). Sequence alignment and application of newly generated homology models for human and mouse 11ß-HSD2 revealed significant differences in the C-terminal region and the substrate binding pocket. Exchange of the C-terminus and substitution of residues Leu170,Ile172 in mouse 11ß-HSD2 by the corresponding residues His170,Glu172 of the human enzyme resulted in a gain of sensitivity to itraconazole and posaconazole, resembling human 11ß-HSD2. The results provide an explanation for the observed species-specific 11ß-HSD2 inhibition by the studied azole antifungals. The obtained structure-activity relationship information should facilitate future assessments of 11ß-HSD2 inhibitors and aid choosing adequate animal models for efficacy and safety studies.

Impact of 17ß-HSD12, the 3-ketoacyl-CoA reductase of long-chain fatty acid synthesis, on breast cancer cell proliferation and migration.

Metabolic reprogramming of tumor cells involves upregulation of fatty acid (FA) synthesis to support high bioenergetic demands and membrane synthesis. This has been shown for cytosolic synthesis of FAs with up to 16 carbon atoms. Synthesis of long-chain fatty acids (LCFAs), including ω-6 and ω-3 polyunsaturated FAs, takes place at the endoplasmic reticulum. Despite increasing evidence for an important role of LCFAs in cancer, the impact of their synthesis in cancer cell growth has scarcely been studied. Here, we demonstrated that silencing of 17ß-hydroxysteroid dehydrogenase type 12 (17ß-HSD12), essentially catalyzing the 3-ketoacyl-CoA reduction step in LCFA production, modulates proliferation and migration of breast cancer cells in a cell line-dependent manner. Increased proliferation and migration after 17ß-HSD12 knockdown were partly mediated by metabolism of arachidonic acid towards COX2 and CYP1B1-derived eicosanoids. Decreased proliferation was rescued by increased glucose concentration and was preceded by reduced ATP production through oxidative phosphorylation and spare respiratory capacity. In addition, 17ß-HSD12 silencing was accompanied by alterations in unfolded protein response, including a decrease in CHOP expression and increase in eIF2α activation and the folding chaperone ERp44. Our study highlights the significance of LCFA biosynthesis for tumor cell physiology and unveils unknown aspects of breast cancer cell heterogeneity.

Ca2+ mobilization-dependent reduction of the endoplasmic reticulum lumen is due to influx of cytosolic glutathione.

BACKGROUND: The lumen of the endoplasmic reticulum (ER) acts as a cellular Ca2+ store and a site for oxidative protein folding, which is controlled by the reduced glutathione (GSH) and glutathione-disulfide (GSSG) redox pair. Although depletion of luminal Ca2+ from the ER provokes a rapid and reversible shift towards a more reducing poise in the ER, the underlying molecular basis remains unclear. RESULTS: We found that Ca2+ mobilization-dependent ER luminal reduction was sensitive to inhibition of GSH synthesis or dilution of cytosolic GSH by selective permeabilization of the plasma membrane. A glutathione-centered mechanism was further indicated by increased ER luminal glutathione levels in response to Ca2+ efflux. Inducible reduction of the ER lumen by GSH flux was independent of the Ca2+-binding chaperone calreticulin, which has previously been implicated in this process. However, opening the translocon channel by puromycin or addition of cyclosporine A mimicked the GSH-related effect of Ca2+ mobilization. While the action of puromycin was ascribable to Ca2+ leakage from the ER, the mechanism of cyclosporine A-induced GSH flux was independent of calcineurin and cyclophilins A and B and remained unclear. CONCLUSIONS: Our data strongly suggest that ER influx of cytosolic GSH, rather than inhibition of local oxidoreductases, is responsible for the reductive shift upon Ca2+ mobilization. We postulate the existence of a Ca2+- and cyclosporine A-sensitive GSH transporter in the ER membrane. These findings have important implications for ER redox homeostasis under normal physiology and ER stress.

Salt-Sensitive Hypertension in GR+/- Rats Is Accompanied with Dysregulation in Adrenal Soluble Epoxide Hydrolase and Polyunsaturated Fatty Acid Pathways.

Mutations within the glucocorticoid receptor (GR) gene locus lead to glucocorticoid resistance which is characterized by several clinical symptoms such as adrenal gland hyperplasia and salt-sensitive hypertension, although the underlying mechanisms are still unknown. We studied GR haploinsufficient (GR+/-) Sprague Dawley rats which, on a standard diet, showed significantly increased plasma aldosterone and corticosterone levels and an adrenocortex hyperplasia accompanied by a normal systolic blood pressure. Following a high salt diet, these rats developed salt-sensitive hypertension and maintained elevated enzyme-soluble epoxide hydrolase (sEH) in adrenal glands, while sEH was significantly decreased in wild-type rats. Furthermore, GR+/- rats showed dysregulation of the equilibrated linoleic and arachidonic acid pathways, with a significant increase of less active metabolites such as 8,9-DiHETrE. In Sprague Dawley rats, GR haploinsufficiency induced steroid disturbances, which provoked hypertension only in combination with high salt intake, which was accompanied by disturbances in sEH and fatty acid metabolism. Our results suggest that sEH inhibition could be a potential target to treat hypertension in patients with GR haploinsufficiency.

Posaconazole Serum Drug Levels Associated With Pseudohyperaldosteronism.

BACKGROUND: Posaconazole tablets are well tolerated and efficacious in the prophylaxis and treatment of aspergillosis, mucormycosis, and other invasive fungal infections. There have been case reports of posaconazole-induced pseudohyperaldosteronism (PIPH); however, its occurrence and association with serum posaconazole drug levels have not previously been investigated. METHODS: In this single-center, retrospective, observational study, we examined the occurrence of PIPH in outpatients newly starting posaconazole and evaluated differences in serum posaconazole concentrations and clinical characteristics between those with and without this syndrome. RESULTS: Sixty-nine patients receiving posaconazole were included, of whom 16 (23.2%) met the definition of PIPH. Patients with PIPH were significantly older (61.1 vs 44.7 years, P = .007) and more frequently had hypertension prior to starting posaconazole (68.8% vs 32.1%, P = .009). Patients with PIPH had a significantly higher median serum posaconazole level than those without PIPH (3.0 vs 1.2 µg/mL, P ≤ .0001). There was a positive correlation between serum posaconazole levels and changes in systolic blood pressure (r = .37, P = .01), a negative correlation between serum posaconazole levels and changes in serum potassium (r = -.39, P = .006), and a positive correlation between serum posaconazole levels and serum 11-deoxycortisol (r = .69, P < .0001). CONCLUSIONS: Posaconazole is associated with secondary hypertension and hypokalemia, consistent with pseudohyperaldosteronism, and development is associated with higher serum posaconazole concentrations, older age, and baseline hypertension.

Management of posaconazole-induced pseudohyperaldosteronism.

BACKGROUND: Posaconazole-induced pseudohyperaldosteronism (PIPH) has been associated with elevated posaconazole serum concentrations. Clinicians are faced with the difficult task of managing patients with PIPH while maintaining the efficacy of antifungal therapy. Commonly, modifications to posaconazole therapy are utilized in managing PIPH, including dosage reduction of posaconazole or switch to an alternative antifungal. OBJECTIVES: To characterize the management of patients diagnosed with PIPH and their response to various therapeutic interventions. METHODS: We retrospectively reviewed 20 consecutive adult patients diagnosed with PIPH. Patient data collected included blood pressure, electrolytes, endocrine laboratory values and posaconazole serum concentrations collected before and after therapeutic intervention. RESULTS: Of 20 patients included, 17 patients (85%) underwent therapeutic modification, with posaconazole dose reduction (n = 11) as the most common change. Other modifications included discontinuation (n = 3), switch to an alternative antifungal (n = 2) and addition of spironolactone (n = 1). Clinical improvement (decrease in systolic blood pressure and increase in serum potassium) was observed in 9 of 17 patients (52.9%). An average decrease in systolic blood pressure of 7.1 mmHg and increase in serum potassium of 0.22 mmol/L was observed following therapeutic modification. CONCLUSIONS: We report our experience with PIPH management, for which there is no universally effective strategy. We utilized a stepwise approach for management, starting with posaconazole dose reduction and repeat assessment of clinical and laboratory parameters. If resolution of PIPH is not achieved, an alternative triazole antifungal or the addition of an aldosterone antagonist are additional potential interventions. It is possible for PIPH to persist after therapeutic modification despite these interventions. Thus, early diagnosis and continuous monitoring is warranted.

Drug-induced endocrine blood pressure elevation.

Patients with uncontrolled hypertension are at risk for cardiovascular complications. The majority of them suffers from unidentified forms of hypertension and a fraction has so-called secondary hypertension with an identifiable cause. The patient's medications, its use of certain herbal supplements and over-the-counter agents represent potential causal factors for secondary hypertension that are often overlooked. The current review focuses on drugs that are likely to elevate blood pressure by affecting the human endocrine system at the level of steroid synthesis or metabolism, mineralocorticoid receptor activity, or by affecting the catecholaminergic system. Drugs with known adverse effects but where benefits outweigh their risks, drug candidates and market withdrawals are reviewed. Finally, potential therapeutic strategies are discussed.

Finding New Molecular Targets of Familiar Natural Products Using In Silico Target Prediction.

Natural products comprise a rich reservoir for innovative drug leads and are a constant source of bioactive compounds. To find pharmacological targets for new or already known natural products using modern computer-aided methods is a current endeavor in drug discovery. Nature's treasures, however, could be used more effectively. Yet, reliable pipelines for the large-scale target prediction of natural products are still rare. We developed an in silico workflow consisting of four independent, stand-alone target prediction tools and evaluated its performance on dihydrochalcones (DHCs)-a well-known class of natural products. Thereby, we revealed four previously unreported protein targets for DHCs, namely 5-lipoxygenase, cyclooxygenase-1, 17ß-hydroxysteroid dehydrogenase 3, and aldo-keto reductase 1C3. Moreover, we provide a thorough strategy on how to perform computational target predictions and guidance on using the respective tools.

11ß-Hydroxysteroid dehydrogenases control access of 7ß,27-dihydroxycholesterol to retinoid-related orphan receptor γ.

Oxysterols previously were considered intermediates of bile acid and steroid hormone biosynthetic pathways. However, recent research has emphasized the roles of oxysterols in essential physiologic processes and in various diseases. Despite these discoveries, the metabolic pathways leading to the different oxysterols are still largely unknown and the biosynthetic origin of several oxysterols remains unidentified. Earlier studies demonstrated that the glucocorticoid metabolizing enzymes, 11ß-hydroxysteroid dehydrogenase (11ß-HSD) types 1 and 2, interconvert 7-ketocholesterol (7kC) and 7ß-hydroxycholesterol (7ßOHC). We examined the role of 11ß-HSDs in the enzymatic control of the intracellular availability of 7ß,27-dihydroxycholesterol (7ß27OHC), a retinoid-related orphan receptor γ (RORγ) ligand. We used microsomal preparations of cells expressing recombinant 11ß-HSD1 and 11ß-HSD2 to assess whether 7ß27OHC and 7-keto,27-hydroxycholesterol (7k27OHC) are substrates of these enzymes. Binding of 7ß27OHC and 7k27OHC to 11ß-HSDs was studied by molecular modeling. To our knowledge, the stereospecific oxoreduction of 7k27OHC to 7ß27OHC by human 11ß-HSD1 and the reverse oxidation reaction of 7ß27OHC to 7k27OHC by human 11ß-HSD2 were demonstrated for the first time. Apparent enzyme affinities of 11ß-HSDs for these novel substrates were equal to or higher than those of the glucocorticoids. This is supported by the fact that 7k27OHC and 7ß27OHC are potent inhibitors of the 11ß-HSD1-dependent oxoreduction of cortisone and the 11ß-HSD2-dependent oxidation of cortisol, respectively. Furthermore, molecular docking calculations explained stereospecific enzyme activities. Finally, using an inducible RORγ reporter system, we showed that 11ß-HSD1 and 11ß-HSD2 controlled RORγ activity. These findings revealed a novel glucocorticoid-independent prereceptor regulation mechanism by 11ß-HSDs that warrants further investigation.