Development of a novel spatiotemporal depletion system for cellular cholesterol

Cholesterol is an essential component of mammalian cell membranes whose subcellular concentration and function are tightly regulated by de novo biosynthesis, transport, and storage. Although recent reports have suggested diverse functions of cellular cholesterol in different subcellular membranes, systematic investigation of its site-specific roles has been hampered by the lack of a methodology for spatiotemporal manipulation of cellular cholesterol levels. Here, we report the development of a new cholesterol depletion system that allows for spatiotemporal manipulation of intracellular cholesterol levels. This system utilizes a genetically encoded cholesterol oxidase whose intrinsic membrane binding activity is engineered in such a way that its membrane targeting can be controlled in a spatiotemporally specific manner via chemically induced dimerization. In combination with in situ quantitative imaging of cholesterol and signaling activity measurements, this system allows for unambiguous determination of site-specific functions of cholesterol in different membranes, including the plasma membrane and the lysosomal membrane.     

Relationship between hepatic and mitochondrial ceramides: a novel in vivo method to track ceramide synthesis

Ceramides (CERs) are key intermediate sphingolipids implicated in contributing to mitochondrial dysfunction and the development of multiple metabolic conditions. Despite the growing evidence of CER role in disease risk, kinetic methods to measure CER turnover are lacking, particularly using in vivo models. The utility of orally administered ¹³C₃, ¹⁵N l-serine, dissolved in drinking water, was tested to quantify CER 18:1/16:0 synthesis in 10-week-old male and female C57Bl/6 mice. To generate isotopic labeling curves, animals consumed either a control diet or high-fat diet (HFD; n = 24/diet) for 2 weeks and varied in the duration of the consumption of serine-labeled water (0, 1, 2, 4, 7, or 12 days; n = 4 animals/day/diet). Unlabeled and labeled hepatic and mitochondrial CERs were quantified using liquid chromatography tandem MS. Total hepatic CER content did not differ between the two diet groups, whereas total mitochondrial CERs increased with HFD feeding (60%, P < 0.001). Within hepatic and mitochondrial pools, HFD induced greater saturated CER concentrations (P < 0.05) and significantly elevated absolute turnover of 16:0 mitochondrial CER (mitochondria: 59%, P < 0.001 vs. liver: 15%, P = 0.256). The data suggest cellular redistribution of CERs because of the HFD. These data demonstrate that a 2-week HFD alters the turnover and content of mitochondrial CERs. Given the growing data on CERs contributing to hepatic mitochondrial dysfunction and the progression of multiple metabolic diseases, this method may now be used to investigate how CER turnover is altered in these conditions.     

A Dictyostelium discoideum mitochondrial fluorescent tagging vector that does not affect respiratory function

Visualizing mitochondria in living Dictyostelium discoideum cells using fluorescent dyes is often problematic due to variability in staining, metabolism of the dyes, and unknown potential effects of the dyes on mitochondrial function. We show that fluorescent labelling of mitochondria, using an N-terminal mitochondrial localization sequence derived from the D. discoideum protein GcvH1 (glycine cleavage system H1) attached to a red fluorescent protein enables clear mitochondrial imaging. We also show that this labelling has no effect upon mitochondria load or respiratory function.     

Establishment of a novel anti-TROP2 monoclonal antibody TrMab-29 for immunohistochemical analysis

TROP2 is a type I transmembrane glycoprotein originally identified in human trophoblast cells that is overexpressed in several types of cancer. To better understand the role of TROP2 in cancer, we herein aimed to develop a sensitive and specific anti-TROP2 monoclonal antibody (mAb) for use in flow cytometry, Western blot, and immunohistochemistry using a Cell-Based Immunization and Screening (CBIS) method. Two mice were immunized with N-terminal PA-tagged and C-terminal RAP/MAP-tagged TROP2-overexpressed Chinese hamster ovary (CHO)–K1 cells (CHO/PA-TROP2-RAP-MAP), and hybridomas showing strong signals from PA-tagged TROP2-overexpressed CHO–K1 cells (CHO/TROP2-PA) and weak-to-no signals from CHO–K1 cells were selected using flow cytometry. We demonstrated using flow cytometry that the established anti-TROP2 mAb, TrMab-29 (mouse IgG₁ kappa), detected TROP2 in MCF7 breast cancer cell line as well as CHO/TROP2-PA cells. Western blot analysis showed a 40 kDa band in lysates prepared from both CHO/TROP2-PA and MCF7 cells. Furthermore, TROP2 was strongly detected by immunohistochemical analysis using TrMab-29, indicating that TrMab-29 may be a valuable tool for the detection of TROP2 in cancer.     

A current view on Tau protein phosphorylation in Alzheimer's disease

The functions of the neuronal microtubule-associated protein Tau in the central nervous system are regulated by manifold posttranslational modifications at more than 50 sites. Tau in healthy neurons carries multiple phosphate groups, mostly in its microtubule assembly domain. Elevated phosphorylation and aggregation of Tau are widely considered pathological hallmarks in Alzheimer’s disease (AD) and other tauopathies, triggering the quest for Tau posttranslational modifications in the disease context. However, the phosphorylation patterns of physiological and pathological Tau are surprisingly similar and heterogenous, making it difficult to identify specific modifications as therapeutic targets and biomarkers for AD. We present a concise summary of - and view on - important previous and recent advances in Tau phosphorylation analysis in the context of AD.     

The Risk Factors for Developing Clustered Vertebral Compression Fractures: A Single-Center Study

ObjectiveVertebral compression fractures (VCFs) are common among elderly individuals, but clustered VCFs (C-VCFs) are rare and more severe. The risk factors for C-VCFs remain unclear. Thus, we investigated the clinical characteristics of C-VCFs to identify the imminent fracture risk and improve the treatment for such patients.MethodsWe reviewed the records of patients with VCF at a single medical center between January 2011 and September 2020. Patients who had 4 or more VCFs within 1 year were categorized into the C-VCF group, and the remaining patients were paired into the control group at a ratio of 2:1. We collected demographic, clinical, laboratory, and radiologic information regarding these patients. Univariate analyses, stratified analyses, and multivariate logistic regression were performed to identify the risk factors for C-VCFs.ResultsA total of 156 patients were enrolled, of whom 52 were patients with C-VCF. Patients with C-VCF had more severe fractures and pain, with fractures occurring at uncommon sites of the spine. The independent risk factors for C-VCFs included glucocorticoid (GC) treatment (P < .001; hazard ratio [HR], 12.7), recent fracture history (P = .021; HR, 5.5), and lower trabecular bone score (TBS) (P = .044; HR, 1.6). TBS and bone mineral density had greater predictive values in patients without GC treatment (P < .001). Sex, age, and bone turnover biomarkers were not independent risk factors for C-VCFs.ConclusionC-VCFs are rare adverse consequences of severe osteoporosis, for which GC treatment, recent fracture history, and lower TBS are unique risk factors that are valuable for the early identification and prevention of C-VCFs.     

Autophagic degradation of HAS2 in endothelial cells: A novel mechanism to regulate angiogenesis

Hyaluronan plays a key role in regulating inflammation and tumor angiogenesis. Of the three transmembrane hyaluronan synthases, HAS2 is the main pro-angiogenic enzyme responsible for excessive hyaluronan production. We discovered that HAS2 was degraded in vascular endothelial cells via autophagy evoked by nutrient deprivation, mTOR inhibition, or pro-autophagic proteoglycan fragments endorepellin and endostatin. Using live-cell and super-resolution confocal microscopy, we found that protracted autophagy evoked a dynamic interaction between HAS2 and ATG9A, a key transmembrane autophagic protein. This regulatory axis of HAS2 degradation occurred in various cell types and species and in vivo upon nutrient deprivation. Inhibiting in vivo autophagic flux via chloroquine showed increased levels of HAS2 in the heart and aorta. Functionally, autophagic induction via endorepellin or mTOR inhibition markedly suppressed extracellular hyaluronan production in vascular endothelial cells and inhibited ex vivo angiogenic sprouting. Thus, we propose autophagy as a novel catabolic mechanism regulating hyaluronan production in endothelial cells and demonstrate a new link between autophagy and angiogenesis that could lead to potential therapeutic modalities for angiogenesis.     

Adapting protein sequences for optimized therapeutic efficacy

Therapeutic proteins alleviate disease pathology by supplementing missing or defective native proteins, sequestering superfluous proteins, or by acting through designed non-natural mechanisms. Although therapeutic proteins often have the same amino acid sequence as their native counterpart, their maturation paths from expression to the site of physiological activity are inherently different, and optimizing protein sequences for properties that 100s of millions of years of evolution did not need to address presents an opportunity to develop better biological treatments. Because therapeutic proteins are inherently non-natural entities, optimization for their desired function should be considered analogous to that of small molecule drug candidates, which are optimized through expansive combinatorial variation by the medicinal chemist. Here, we review recent successes and challenges of protein engineering for optimized therapeutic efficacy.     

Enhancing native chemical ligation for challenging chemical protein syntheses

Native chemical ligation has enabled the chemical synthesis of proteins for a wide variety of applications (e.g., mirror-image proteins). However, inefficiencies of this chemoselective ligation in the context of large or otherwise challenging protein targets can limit the practical scope of chemical protein synthesis. In this review, we focus on recent developments aimed at enhancing and expanding native chemical ligation for challenging protein syntheses. Chemical auxiliaries, use of selenium chemistry, and templating all enable ligations at otherwise suboptimal junctions. The continuing development of these tools is making the chemical synthesis of large proteins increasingly accessible.     

C-Phycocyanin-a novel protein from Spirulina platensis- In vivo toxicity,antioxidant and immunomodulatory studies

A pigment-protein highly dominant in Spirulina is known as C-Phycocyanin. Earlier, in vitro studies has shown that C-phycocyanin is having many biological activities like antioxidant and anti-inflammatory activities, antiplatelet, hepatoprotective, and cholesterol-lowering properties. Interestingly, there are scanty in vivo experimental findings on the immunomodulatory and antioxidant effects of C-phycocyanin. This work is aimed at in vivo evaluation of the effects of C-phycocyanin on immunomodulation and antioxidant potential in Balb/c mice. Our results of in vivo toxicity, immunomodulatory and antioxidant effects of C-Phycocyanin suggests that C-phycocyanin is very safe for consumption and having substantial antioxidant potential and also possess immunomodulatory activities in Balb/c mice in a dosage dependent manner. C-phycocyanin doesn’t cause acute and subacute toxicity in the animal model (male, Balb/c mice) studied. We have reported that C-phycocyanin exhibited in vivo immunomodulation performance in this animal model.     

Osilodrostat: A Review of Recent Clinical Studies and Practical Recommendations for its Use in the Treatment of Cushing Disease

ObjectiveCushing disease (CD) is characterized by chronic hypercortisolism caused by an adrenocorticotropic hormone-secreting pituitary adenoma. Surgery remains the first-line treatment option; however, medical therapy is essential if surgery is contraindicated or fails to achieve remission or when recurrence occurs after surgical remission. Osilodrostat (Isturisa), a novel steroidogenic inhibitor, is now approved for the treatment of CD in the United States and Cushing syndrome in Europe. Herein, we review pharmacology and data on the efficacy, safety, and clinical use of osilodrostat and provide guidance on its use in treating patients with CD.MethodsWe reviewed the literature and published clinical trial data of osilodrostat use in patients with Cushing syndrome. Detailed information related to the clinical assessment of osilodrostat use, potential drug-to-drug interactions, drug initiation, dose titration, and the monitoring of drug tolerability were discussed.ResultsClinical trial data demonstrated that osilodrostat, by virtue of inhibiting 11-β hydroxylase, potently and rapidly decreased the 24-hour urinary free cortisol levels and sustained these reductions, with improved glycemia, blood pressure, body weight, and quality of life as well as lessened depression. Osilodrostat may interact with certain drugs, resulting in QT prolongation, which requires careful assessment of concomitant medications and periodic monitoring using electrocardiogram, respectively. The common adverse effects include adrenal insufficiency, hypokalemia, edema, and hyperandrogenic symptoms, which can be minimized using a slower up-titration dosing regimen.ConclusionOsilodrostat is an effective, new treatment option for CD, with positive effects on cardiovascular and quality of life parameters as well as tolerable adverse effects. This article provides a review of the pharmacology of osilodrostat and offers practical recommendations on the use of osilodrostat to treat CD.     

Targeted lipidomics reveals a novel role for glucosylceramides in glucose response

The addition of excess glucose to the diet drives a coordinated response of lipid metabolism pathways to tune the membrane composition to the altered diet. Here, we have employed targeted lipidomic approaches to quantify the specific changes in the phospholipid and sphingolipid populations that occur in elevated glucose conditions. The lipids within wild-type Caenorhabditis elegans are strikingly stable with no significant changes identified in our global mass spectrometry–based analysis. Previous work has identified ELO-5, an elongase that is critical for the synthesis of monomethyl branched-chain fatty acids (mmBCFAs), as essential for surviving elevated glucose conditions. Therefore, we performed targeted lipidomics on elo-5 RNAi-fed animals and identified several significant changes in these animals in lipid species that contain mmBCFAs as well as in species that do not contain mmBCFAs. Of particular note, we identified a specific glucosylceramide (GlcCer 17:1;O2/22:0;O) that is also significantly upregulated with glucose in wild-type animals. Furthermore, compromising the production of the glucosylceramide pool with elo-3 or cgt-3 RNAi leads to premature death in glucose-fed animals. Taken together, our lipid analysis has expanded the mechanistic understanding of metabolic rewiring with glucose feeding and has identified a new role for the GlcCer 17:1;O2/22:0;O.     

KCNJ5 Mutation Contributes to Complete Clinical Success in Aldosterone-Producing Adenoma: A Study From a Single Center

ObjectiveThe KCNJ5 mutation is the most frequent mutation in aldosterone-producing adenoma (APA). We aimed to illustrate the relationship between KCNJ5 and prognosis after adrenalectomy as a guide for further treatment.MethodsOur study included 458 patients with APA. Tumor tissues were screened for somatic mutations in KCNJ5 hot-spot regions. We performed a retrospective analysis to identify correlations between KCNJ5 and clinical outcomes in 334 patients with adrenal venous sampling lateralization.ResultsSomatic KCNJ5 mutations were identified in 324 of 458 patients with APA (70.7%). Compared with the KCNJ5-wild type patients, patients with KCNJ5 mutations were younger, had a higher proportion of women, and had shorter durations of hypertension, lower body mass indexes (BMIs), and lower systolic blood pressure values (P < .05). During follow-up, among the 334 patients with APA with adrenal venous sampling lateralization, 320 (95.8%) presented complete biochemical success and 187 (56.0%) presented complete clinical success. One hundred eighty-seven patients with primary aldosteronism who achieved complete clinical success presented the following characteristics: age <40 years (78.7%), BMI <24 kg/m² (71.0%), hypertension duration <5 years (78.4%), females (66.9%), and KCNJ5 mutation (65.5%). A multivariate logistic regression analysis identified BMI, hypertension duration, and KCNJ5 mutation as independent predictors of complete clinical success.ConclusionThe prevalence of KCNJ5 mutations was 70.7%. KCNJ5 mutation is a protective factor of complete clinical success, while BMI and hypertension duration were risk factors of incomplete clinical success.     

The Evaluation of Low- and High-Dose Steroid Treatments in Subacute Thyroiditis: A Retrospective Observational Study

ObjectiveThe optimal steroid regimen in the treatment of subacute thyroiditis (SAT) is controversial. This study aims to compare low- and high-dose steroid regimens in the treatment of SAT.MethodsA single-center, retrospective observational cohort study with up to 1 year of follow-up was conducted. A total of 44 patients in the 16-mg methylprednisolone (MPS) group and 47 patients in the 48-mg MPS group were enrolled. Clinical and laboratory findings from the time of diagnosis to 1-year of the follow-up were assessed. Treatment response, recurrence, and hypothyroidism (HPT) rates were evaluated.ResultsClinical symptoms, sedimentation rates, C-reactive protein, and thyroid hormone levels of the patients were similar in the 2 groups. Recovery was achieved in all patients at the end of the treatments; however, treatment duration needed to be extended for 6 (13.6%) and 1 (2.1%) of the patients in the 16-mg and 48-mg MPS groups, respectively. The 48-mg MPS group had a higher SAT recurrence rate than the 16-mg MPS group (P = .04). Logistic regression analysis suggested that a lower thyroid-stimulating hormone level at the end of the treatment was a predictor of recurrence (β = –0.544, P = .014, 95% CI: 0.376-0.895). While the transient HPT rate was 10 (21.3%) and 10 (22.7%) in the 48-mg and 16-mg MPS groups, respectively, a permanent HPT developed in 5 (10.6%) of patients in the 48-mg MPS and 3 (6.8%) in the 16-mg MPS group. The permanent and transient HPT rates were determined to be similar in the low- and high-dose groups (P > .05).ConclusionLow-dose steroid therapy may be sufficient to achieve a complete recovery and better outcomes in SAT.     

The Effect of Gender-Affirming Hormone Therapy on the Risk of Subclinical Atherosclerosis in the Transgender Population: A Systematic Review

ObjectiveThe impact of gender-affirming hormone therapy (GAHT) on cardiovascular (CV) health is still not entirely established. A systematic review was conducted to summarize the evidence on the risk of subclinical atherosclerosis in transgender people receiving GAHT.MethodsA systematic review was performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, and data were searched in PubMed, LILACS, EMBASE, and Scopus databases for cohort, case-control, and cross-sectional studies or randomized clinical trials, including transgender people receiving GAHT. Transgender men and women before and during/after GAHT for at least 2 months, compared with cisgender men and women or hormonally untreated transgender persons. Studies reporting changes in variables related to endothelial function, arterial stiffness, autonomic function, and blood markers of inflammation/coagulation associated with CV risk were included.ResultsFrom 159 potentially eligible studies initially identified, 12 were included in the systematic review (8 cross-sectional and 4 cohort studies). Studies of trans men receiving GAHT reported increased carotid thickness, brachial-ankle pulse wave velocity, and decreased vasodilation. Studies of trans women receiving GAHT reported decreased interleukin 6, plasminogen activator inhibitor-1, and tissue plasminogen activator levels and brachial-ankle pulse wave velocity, with variations in flow-mediated dilation and arterial stiffness depending on the type of treatment and route of administration.ConclusionsThe results suggest that GAHT is associated with an increased risk of subclinical atherosclerosis in transgender men but may have either neutral or beneficial effects in transgender women. The evidence produced is not entirely conclusive, suggesting that additional studies are warranted in the context of primary prevention of CV disease in the transgender population receiving GAHT.Systematic Review RegistrationPROSPERO, identifier CRD42022323757.     

Predictors of Prolonged Euthyroidism After Radioactive Iodine Treatment for Graves’ Disease: A Pilot Study

ObjectivePatients with Graves’ disease who remain hyperthyroid under the treatment of antithyroid drugs (ATD) or cannot tolerate ATD usually receive radioactive iodine (RAI) to control disease activity. This pilot study aimed to identify predictors of prolonged euthyroidism > 12 months after receiving RAI.MethodsDemographic, clinical, and laboratory data from 117 patients receiving RAI were retrospectively collected, including age, gender, body surface area, smoking status, free thyroxine, thyrotropin, thyrotropin binding inhibiting immunoglobulin, microsomal antibody, thyroglobulin antibody, medication history, and thyroid volume. Only 85 patients without missing values were included in statistical analysis. The calculated RAI dose was the estimated thyroid volume × 0.4. The difference and ratio between the actual and calculated RAI doses were examined. A stepwise logistic regression analysis was conducted to identify important predictors of prolonged euthyroidism > 12 months. The cut-off values for discretizing continuous covariates were estimated by fitting generalized additive models.ResultsAmong the 85 patients on RAI, 18 (21.2%) achieved prolonged euthyroidism > 12 months, 38 (44.7%) remained hyperthyroid with decreased ATD doses, but 29 (34.1%) suffered permanent hypothyroidism and needed long-term levothyroxine. Logistic regression analysis revealed that patients with age > 66 years, 33 < age ≤ 66 years, quitting smoking vs nonsmoking or current smoking, 600 < micorsomal antibody ≤ 1729 IU/mL, 47% < thyrotropin binding inhibiting immunoglobulin ≤ 81%, 7 < thyroglobulin antibody ≤ 162 IU/mL, 0.63 < ratio between actual and calculated RAI doses ≤ 1.96, or taking hydroxychloroquine would have a higher chance of reaching prolonged euthyroidism > 12 months after receiving RAI. Its area under the Receiver Operating Characteristic (ROC) curve was 0.932.ConclusionPatients with Graves’ disease who received an actual RAI dose close to the calculated RAI dose achieved prolonged euthyroidism > 12 months if they also took hydroxychloroquine during RAI treatment.     

Discovery of ASP5286: A novel non-immunosuppressive cyclophilin inhibitor for the treatment of HCV

Evidence indicates that hepatitis C virus (HCV) utilizes cellular cyclophilin proteins in its replication, and cyclophilin inhibitors represent a new class of anti-HCV agents. We have established an efficient synthetic methodology to generate FR901459 derivatives via N, O-acyl migration reaction while avoiding total synthesis. Through a detailed structure–activity relationship study, we improved anti-HCV activity while decreasing immunosuppressive activity. Additionally, we discovered the importance of substitution at the 3 position for not only improving anti-HCV activity but also pharmacokinetic profile. Finally, by striking an appropriate balance between potency, solubility, and permeability, we discovered ASP5286 (13) as a potential clinical candidate for anti-HCV therapy.