Functional Characterization of Monomeric GTPase Rab1 in the Secretory Pathway of Leishmania

Leishmania secretes a large number of its effectors to the extracellular milieu. However, regulation of the secretory pathway in Leishmania is not well characterized. Here, we report the cloning, expression, and characterization of the Rab1 homologue from Leishmania. We have found that LdRab1 localizes in Golgi in Leishmania. To understand the role of LdRab1 in the secretory pathway of Leishmania, we have generated transgenic parasites overexpressing GFP-LdRab1:WT, GFP-LdRab1:Q67L (a GTPase-deficient dominant positive mutant of Rab1), and GFP-LdRab1:S22N (a GDP-locked dominant negative mutant of Rab1). Surprisingly, our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N does not disrupt the trafficking and localization of hemoglobin receptor in Leishmania. To determine whether the Rab1-dependent secretory pathway is conserved in parasites, we have analyzed the role of LdRab1 in the secretion of secretory acid phosphatase and Ldgp63 in Leishmania. Our results have shown that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N significantly inhibits the secretion of secretory acid phosphatase by Leishmania. We have also found that overexpression of GFP-LdRab1:Q67L or GFP-LdRab1:S22N retains RFP-Ldgp63 in Golgi and blocks the secretion of Ldgp63, whereas the trafficking of RFP-Ldgp63 in GFP-LdRab1:WT-expressing cells is unaltered in comparison with control cells. Taken together, our results have shown that the Rab1-regulated secretory pathway is well conserved, and hemoglobin receptor trafficking follows an Rab1-independent secretory pathway in Leishmania.     

The Prevalence of Dysglycemia-Based Chronic Disease in a European Population – a New Paradigm to Address Diabetes Burden: A Kardiovize Study

ObjectiveTo determine the prevalence rate and associated risk factors for each stage of the Dysglycemia-Based Chronic Disease (DBCD) model, which 4 distinct stages and prompts early prevention to avert Diabetes and cardiometabolic complications.MethodsSubjects between 25 and 64 years old from a random population-based sample were evaluated in Czechia from 2013 to 2014 using a cross-sectional design. DBCD stages were: stage 1 “insulin resistance” (inferred risk from abdominal obesity or a family history of diabetes); stage 2 “prediabetes”(fasting glucose between 5.6 and 6.9 mmol/L); stage 3 “type 2 diabetes (T2D)” (self-report of T2D or fasting glucose ≥7 mmol/L); and stage 4 “vascular complications” (T2D with cardiovascular disease).ResultsA total of 2147 subjects were included (57.8% women) with a median age of 48 years. The prevalence of each DBCD stage were as follows: 54.2% (stage 1); 10.3% (stage 2), 3.7% (stage 3); and 1.2% (stage 4). Stages 2 to 4 were more frequent in men and stage 1 in women (P < .001). Using binary logistic regression analysis adjusting by age/sex, all DBCD stages were strongly associated with abnormal adiposity, hypertension, dyslipidemia, and smoking status. Subjects with lower educational levels and lower income were more likely to present DBCD.ConclusionUsing the new DBCD framework and available metrics, 69.4% of the population had DBCD, identifying far more people at risk than a simple prevalence rate for T2D (9.2% in Czechia, 2013-2014). All stages were associated with traditional cardiometabolic risk factors, implicating common pathophysiologic mechanisms and a potential for early preventive care. The social determinants of health were related with all DBCD stages in alarming proportions and will need to be further studied.     

Predictors of Severe COVID-19 in Patients With Diabetes: A Multicenter Review

ObjectiveDiabetes is an independent risk factor for severe SARS-CoV-2 infections. This study aims to elucidate the risk factors predictive of more severe outcomes in patients with diabetes by comparing the clinical characteristics of those requiring inpatient admissions with those who remain outpatient.MethodsA retrospective review identified 832 patients—631 inpatients and 201 outpatients—with diabetes and a positive SARS-CoV-2 test result between March 1 and June 15, 2020. Comparisons between the outpatient and inpatient cohorts were conducted to identify risk factors associated with severity of disease determined by admission rate and mortality. Previous dipeptidyl peptidase 4 inhibitor use and disease outcomes were analyzed.ResultsRisk factors for increased admission included older age (odds ratio [OR], 1.04 [95% CI, 1.01-1.06]; P = .003), the presence of chronic kidney disease (OR, 2.32 [1.26-4.28]; P = .007), and a higher hemoglobin A1c at the time of admission (OR, 1.25 [1.12-1.39]; P < .001). Lower admission rates were seen in those with commercial insurance. Increased mortality was seen in individuals with older age (OR, 1.09 [1.07-1.11]; P < .001), higher body mass index number (OR, 1.04 [1.01-1.07]; P = .003), and higher hemoglobin A1c value at the time of diagnosis of COVID-19 (OR, 1.12 [1.01-1.24]; P = .028) and patients requiring hospitalization. Lower mortality was seen in those with hyperlipidemia. Dipeptidyl peptidase 4 inhibitor use prior to COVID-19 infection was not associated with a decreased hospitalization rate.ConclusionThis retrospective review offers the first analysis of outpatient predictors for admission rate and mortality of COVID-19 in patients with diabetes.     

Rigid domains in proteins: An algorithmic approach to their identification

A rigid domain, defined here as a tertiary structure common to two or more different protein conformations, can be identified numerically from atomic coordinates by finding sets of residues, one in each conformation, such that the distance between any two residues within the set belonging to one conformation is the same as the distance between the two structurally equivalent residues within the set belonging to any other conformation. The distance between two residues is taken to be the distance between their respective α carbon atoms. With the methods of this paper we have found in the deoxy and oxy conformations of the human hemoglobin α₁β₁ dimer a rigid domain closely related to that previously identified by Baldwin and Chothia (J. Mol. Biol. 129:175–220,1979). We provide two algorithms, both using the difference-distance matrix, with which to search for rigid domains directly from atomic coordinates. The first finds all rigid domains in a protein but has storage and processing demands that become prohibitively large with increasing protein size. The second, although not necessarily finding every rigid domain, is computationally tractable for proteins of any size. Because of its efficiency we are able to search protein conformations recursively for groups of non-intersecting domains. Different protein conformations, when aligned by superimposing their respective domain structures; can be examined for structural differences in regions complementing a rigid domain. © 1995 Wiley-Liss, Inc.     

Characterization and bioactivities of M. arvensis,V. officinalis and P. glabrum: In-silico modeling of V. officinalis as a potential drug source

In current study the pharmaceutically active herbs was used against coccidiosis, caused by a protozoan: Eimeria, lead to $ 3 billion loss annually. The aqueous and methanolic extracts of whole plants were applied in-vitro to assess sporulation inhibition (spi) assay and calculated the inhibitory concentration (IC₅₀). For in-vivo study 9 groups of 14 day old broiler chicks were infected with Eimeria tenella and three groups were treated different concentrations of methanolic extracts of Verbena officinalis and Polygonum glabrum post infection. The mean weight gain, oocyst count, diarrhea, biochemical tests, hematology, and histopathology of all groups were analyzed. The herbs were characterized by antioxidant assay, phytochemical screening, Fourier transmission and infrared (FT-IR), Ultra Violet-visible (UV–Vis) spectroscopy and Gas chromatography and mass spectroscopy (GC–MS). The GC–MS identified phyto-compounds of V. officinalis were docked with S-Adenosyl methionine (SAM) synthetase. The in-vitro study revealed that V. officinalis and P. glabrum have minimum IC₅₀ of 0.14 and 12 mg/ml respectively. The in-vivo experiment showed that V. officinalis had significantly high anticoccidial potential with significant hematological profile like drug treated controls. The histology of treated chicks also showed recovery in the studied tissues. The antioxidant assay showed that V. officinalis have 4.19U/mg Superoxide dismutase (SOD) and 33.96 µM/mg Glutathione (GSH) quantities. The chemical characterization confirmed the presence of large number of organic compounds, however Flavonoids found only in V. officinalis, which suggests the anticoccidial potential of V. officinalis because flavonoids as antagonist of thiamine (Prinzo, 1999), because it promotes the carbohydrate synthesis required. Strychane, 1-acetyl-20a-hydroxy-16-methylene has best binding of with target protein with lowest binding score (-6.4 Kcal/mol), suggests its anticoccidial potential in poultry.     

Next-generation polymerized human hemoglobins in hepatic bioreactor simulations

Hepatic hollow fiber (HF) bioreactors can be used to provide temporary support to patients experiencing liver failure. Before being connected to the patient's circulation, cells in the bioreactor must be exposed to a range of physiological O₂ concentrations as observed in the liver sinusoid to ensure proper performance. This zonation in cellular oxygenation promotes differences in hepatocyte phenotype and may better approximate the performance of a real liver within the bioreactor. Polymerized human hemoglobin (PolyhHb) locked in the tense quaternary state (T-state) has the potential to both supply and regulate O₂ transport to cultured hepatocytes in the bioreactor due to its low O₂ affinity. In this study, T-state PolyhHb production and purification processes were optimized to minimize the concentration of low-molecular-weight PolyhHb species in solution. Deconvolution of size-exclusion chromatography spectra was performed to calculate the distribution of polymeric Hb species in the final product. Fluid flow and mass transport within a single fiber of a hepatic HF bioreactor was computationally modeled with finite element methods to simulate the effects of employing T-state PolyhHb to facilitate O₂ transport in a hepatic bioreactor system. Optimal bioreactor performance was defined as having a combined hypoxic and hyperoxic volume fraction in the extracapillary space of less than 0.05 where multiple zones were observed. The Damköhler number and Sherwood number had strong inverse relationships at each cell density and fiber thickness combination. These results suggest that targeting a specific Damköhler number may be beneficial for optimal hepatic HF bioreactor operation.     

Possible effects of 1011 Hz radiation on the oxygen affinity of hemoglobin

When oxygen binds to one of the subunits of hemoglobin, the oxygen affinity of the other subunits is enhanced. This cooperative interaction of the subunits is initiated by the movement of the heme plane toward the proximal side when oxygen binds to the heme. This motion is transmitted to the surface of the globin through a “reaction channel” consisting of a group of atoms whose motion is well correlated. Considering the detailed geometry and X-ray diffraction data of the mean square displacement of the atoms surrounding the heme, a simple model for the heme plane oscillations is developed. Using this model, the natural frequency of oscillations is shown to be ≈5 × 10¹¹ Hz. This result, along with the recent experimental data on the kinetics of the conformational changes of the heme, points to the possibility of radiation influencing the oxygen affinity of hemoglobin. If such an effect exists, it is likely that the oxygen affinity will be enhanced by the radiation.     

Crystallization and preliminary X-ray diffraction studies of a bacterial flavohemoglobin protein

A flavohemoglobin protein (FHP) was isolated from Alcaligenes eutrophus and has been crystallized by vapor diffusion methods using PEG 3350 as precipitant. The crystals of the FAD- and heme-containing protein belong to the monoclinic space group P2₁ with unit cell parameters of 52.2 Å, 85.8 Å, 103.9 Å, and 81.8° corresponding to two molecules per asymmetric unit. The crystals diffract at least to a resolution of 2.0 Å and are suitable for an X-ray structure analysis. © 1995 Wiley-Liss, Inc.     

American Association of Clinical Endocrinology Disease State Clinical Review: Evaluation and Management of Immune Checkpoint Inhibitor-Mediated Endocrinopathies: A Practical Case-Based Clinical Approach

ObjectiveThe aim of this case-based clinical review was to provide a practical approach for clinicians regarding the management of patients with immune checkpoint inhibitor (ICI)-mediated endocrinopathies.MethodsA literature search of PubMed, Embase, and Scopus was conducted using appropriate keywords. The discussions and strategies for the diagnosis and management of ICI-mediated endocrinopathies are based on evidence available from prospective, randomized clinical studies; cohort studies; cross-sectional studies; case-based studies; and an expert consensus.ResultsImmunotherapy with ICIs has transformed the treatment landscape of diverse types of cancers but frequently results in immune-mediated endocrinopathies that can cause acute and persistent morbidity and, rarely, death. The patterns of endocrinopathies differ between the inhibitors of the cytotoxic T-lymphocyte antigen 4 and programmed cell death protein 1 or programmed cell death protein 1 ligand pathways but most often involve the thyroid and pituitary glands. The less common but important presentations include insulin-deficient diabetes mellitus, primary adrenal insufficiency, primary hypoparathyroidism, central diabetes insipidus, primary hypogonadism, and pancreatitis, with or without subsequent progression to diabetes mellitus or exocrine insufficiency.ConclusionIn recent years, with increasing numbers of patients with cancer being treated with ICIs, more clinicians in a variety of specialties have been called upon to diagnose and treat ICI-mediated endocrinopathies. Herein, we reviewed case scenarios of various clinical manifestations and emphasized the need for a high index of clinical suspicion by all clinicians caring for these patients, including endocrinologists, oncologists, primary care providers, and emergency department physicians. We also provided diagnostic and therapeutic approaches for ICI-induced endocrinopathies and proposed that patients on ICI therapy be evaluated and treated by a multidisciplinary team in collaboration with endocrinologists.