Biochemical Evidence Research Articles

A novel mechanism of idiopathic orthostatic hypotension and hypocatecholaminemia due to autoimmunity against aromatic l-Amino acid decarboxylase

Orthostatic hypotension (OH) is a common condition. Many potential etiologies of OH have been identified, but in clinical practice the underlying cause of OH is often unknown. In the present study, we identified a novel and extraordinary etiology of OH. We describe a first case of acquired severe OH with syncope, and the female patient had extremely low levels of catecholamines and serotonin in plasma, urine and cerebrospinal fluid (CSF). Her clinical and biochemical evidence showed a deficiency of the enzyme aromatic l-amino acid decarboxylase (AADC), which converts l-DOPA to dopamine, and 5-hydroxytryptophan to serotonin, respectively. The consequence of pharmacologic stimulation of catecholaminergic nerves and radionuclide examination revealed her catecholaminergic nerves denervation. Moreover, we found that the patient's serum showed presence of autoantibodies against AADC, and that isolated peripheral blood mononuclear cells (PBMCs) from the patient showed cytokine-induced toxicity against AADC. These observations suggest that her autoimmunity against AADC is highly likely to cause toxicity to adrenal medulla and catecholaminergic nerves which contain AADC, resulting in hypocatecholaminemia and severe OH. Administration of vitamin B6, an essential cofactor of AADC, enhanced her residual AADC activity and drastically improved her symptoms. Our data thus provide a new insight into pathogenesis and pathophysiology of OH.

The Catalytic Activity of Human REV1 on Undamaged and Damaged DNA.

Eukaryotic REV1 serves as a scaffold protein for the coordination of DNA polymerases during DNA translesion synthesis. Besides this structural role, REV1 is a Y-family DNA polymerase with its own distributive deoxycytidyl transferase activity. However, data about the accuracy and efficiency of DNA synthesis by REV1 in the literature are contrasting. Here, we expressed and purified the full-length human REV1 from Saccharomyces cerevisiae and characterized its activity on undamaged DNA and a wide range of damaged DNA templates. We demonstrated that REV1 carried out accurate synthesis opposite 8-oxoG and O6-meG with moderate efficiency. It also replicated thymine glycol surprisingly well in an error-prone manner, but was blocked by the intrastrand 1,2-GG cisplatin crosslink. By using the 1,N6-ethenoadenine and 7-deaza-adenine lesions, we have provided biochemical evidence of the importance for REV1 functioning of the Hoogsteen face of template A, the second preferable template after G.

Abstract SY21-02: Coenzyme Q-dependent metabolism: Lessons from structure-function studies of DHODH

Abstract Ubiquinone or coenzyme Q (CoQ) is perhaps best known as a key component of the mitochondrial electron transport chain and as an endogenous antioxidant. However, CoQ has another critical function in cells, acting as an essential cosubstrate for a number of important metabolic enzymes that are associated with the inner mitochondrial membrane, including dihydroorotate dehydrogenase (DHODH), choline dehydrogenase (CHDH), proline dehydrogenase 1 and 2 (PRODH1, PRODH2), and glycerol-3-phosphate dehydrogenase 2 (GPD2). These FAD-containing mitochondrial enzymes are all hypothesized to utilize a two-step ‘ping-pong’ mechanism of catalysis. In this kinetic model, the baseline conformation of the enzyme has specific affinity for its first cosubstrate (dihydroorotate, choline, proline, glycerol-3-phosphate) but not its second cosubstrate (CoQ). Binding of the first cosubstrate to the enzyme results in oxidation of the cosubstrate and reduction of FAD to FADH2. This reduced ‘intermediate’ form of the enzyme releases the byproduct of the first reaction and then binds CoQ. Upon binding of CoQ, FADH2 is oxidized back to FAD and CoQ is reduced to CoQH2. The oxidized form of the enzyme has a low affinity for CoQH2 and CoQH2 is therefore released, restoring the enzyme to its baseline ‘empty’ conformation. Although there is considerable biochemical evidence to support this ‘double-displacement’ model of CoQ-dependent catalysis, it has been challenging to study the structures of these enzymes in their catalytically-active states due to the profound insolubility of CoQ and due to technical challenges associated with producing highly purified recombinant forms of membrane-associated proteins. Perhaps the most well-studied CoQ-dependent metabolic enzyme is DHODH. DHODH catalyzes the fourth and rate-limiting step in the de novo pyrimidine biosynthesis pathway, oxidizing dihydroorotate to orotate, which is then converted to the nucleotide precursor UMP. Due to the critical requirement of rapidly dividing cells for pyrimidines, DHODH has been proposed as a therapeutic target in cancer, and a number of highly potent and highly specific DHODH inhibitors have been developed, all of which act as competitive inhibitors of CoQ. By binding and stabilizing the protein, these inhibitors have made it possible to solve the x-ray crystal structure of DHODH. These structural studies have revealed that the inhibitors (and presumably CoQ) bind in a narrow amphipathic tunnel that spans from the membrane-embedded surface of the protein to its FAD-containing catalytic core. These structural studies have also found that DHO or orotate can bind DHODH when the CoQ tunnel is occupied by drug. Given that the ‘ping-pong’ model of catalysis is predicated on the assumption that cosubstrates and byproducts cannot simultaneously bind enzyme, it would appear that either the ping-pong model does not accurately reflect the catalytic mechanism of DHODH or, alternatively, that the structure of DHODH bound to drug is not an accurate representation of the structure of DHODH bound to CoQ. In order to gain a greater understanding of the structure of the DHODH-CoQ complex, we undertook to solve the x-ray crystal structure of DHODH in complex with decylubiquinone (dUb), a CoQ analog that can act as an electron acceptor for DHODH in vitro. These studies revealed that the x-ray crystal structure of DHODH in its catalytically-active cofactor-bound state deviates in subtle but important ways from the known structure of drug-bound DHODH, providing novel insights into the catalytic mechanism of CoQ-dependent enzymes. Citation Format: Julie-Aurore Losman. Coenzyme Q-dependent metabolism: Lessons from structure-function studies of DHODH [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr SY21-02.

Nuclear factor Y-A3b binds to the SINGLE FLOWER TRUSS promoter and regulates flowering time in tomato.

The control of flowering time is essential for reproductive success and has a major effect on seed and fruit yield and other important agricultural traits in crops. Nuclear factors Y (NF-Ys) are transcription factors that form heterotrimeric protein complexes to regulate gene expression required for diverse biological processes, including flowering time control in plants. However, to our knowledge, there has been no report on mutants of individual NF-YA subunits that promote early flowering phenotype in plants. In this study, we identified SlNF-YA3b, encoding a member of the NF-Y transcription factor family, as a key gene regulating flowering time in tomato. Knockout of NF-YA3b resulted in an early flowering phenotype in tomato, whereas overexpression of NF-YA3b delayed flowering in transgenic tomato plants. NF-YA3b was demonstrated to form heterotrimeric protein complexes with multiple NF-YB/NF-YC heterodimers in yeast three-hybrid assays. Biochemical evidence indicated that NF-YA3b directly binds to the CCAAT cis-elements of the SINGLE FLOWER TRUSS (SFT) promoter to suppress its gene expression. These findings uncovered a critical role of NF-YA3b in regulating flowering time in tomato and could be applied to the management of flowering time in crops.

Epididymo-orchitis with epididymal abscess in a patient with disseminated tuberculosis

Abstract Tuberculosis remains a global health concern, and while primarily affecting the lungs, extrapulmonary manifestations like genitourinary tubercular epididymitis are rare and diagnostically challenging. Accurate differentiation is crucial for appropriate treatment. This case study presents a 34-year-old male with left scrotal swelling, backache, and fever, highlighting the importance of considering tuberculosis in genitourinary conditions. High-resolution sonography revealed an edematous left testis with increased vascularity and hypoechoic nodules. Further imaging, including high-resolution computed tomography thorax and contrast-enhanced magnetic resonance imaging Dorso-lumbar spine, confirmed disseminated tuberculosis. Despite negative urine culture, aspiration cytology from the epididymal collection indicated tubercular etiology. Urogenital tuberculosis, especially isolated epididymal involvement without renal effects, presents diagnostic challenges, often occurring in immunocompromised patients. The case underscores the role of clinical, biochemical, and radiological evidence in establishing a correct diagnosis. High-resolution ultrasonography plays a crucial role in diagnosing scrotal pathologies, and when accompanied by an epididymal collection, further diagnostic steps involving biochemical parameters and aspiration followed by cytoanalysis and culture are essential. The diagnosis of tuberculous epididymitis can be confirmed through acid-fast bacilli (AFB) identification, positive AFB culture, or granulomas seen in a biopsy specimen in the right clinical context. Radiological imaging aids in detecting local and disseminated disease forms, including complications like hydrocele, testicular calcifications, scrotal abscesses, sinus tracks, and fistulous communications.

Efficacy of Newer Nucleos(t)ide Analogs After Hepatitis B Immunoglobulin Discontinuation Against Hepatitis B and D Recurrence in Liver Transplant Recipients.

The use of nucleos(t)ide analogs (NAs) with a high genetic barrier to resistance, namely entecavir and tenofovir, has improved the efficacy of antiviral prophylaxis against hepatitis B virus (HBV) recurrence after liver transplantation (LT). However, the optimal duration and dosage of hepatitis B immunoglobulin (HBIG) administration, particularly in patients transplanted for HBV and hepatitis D virus (HDV) coinfection, remains controversial. We evaluated 28 patients transplanted for HBV/HDV cirrhosis. After LT, each patient received a fixed scheme of low-dose HBIG plus NA for 6 mo post-LT and then continued with long-term NA prophylaxis (entecavir: 8, tenofovir: 20 patients). During 72 mo of follow-up, reappearance of hepatitis B surface antigen at low titers was observed in 1 (3.6%) patient at 33 mo after HBIG discontinuation, which became negative after a single dose of HBIG 1000 IU/L, whereas both serum HBV DNA and HDV RNA remained persistently undetectable and without any clinical or biochemical evidence of HBV/HDV recurrence. We showed for the first time the efficacy of a short, fixed scheme of low-dose HBIG plus NA followed by long-term NA monoprophylaxis against HBV/HDV recurrence after LT, although careful follow-up is needed after HBIG discontinuation, whereas further larger studies are needed to confirm these findings.

The coordinated activities of collagen VI and XII in maintenance of tissue structure, function and repair: evidence for a physical interaction.

Collagen VI and collagen XII are structurally complex collagens of the extracellular matrix (ECM). Like all collagens, type VI and XII both possess triple-helical components that facilitate participation in the ECM network, but collagen VI and XII are distinct from the more abundant fibrillar collagens in that they also possess arrays of structurally globular modules with the capacity to propagate signaling to attached cells. Cell attachment to collagen VI and XII is known to regulate protective, proliferative or developmental processes through a variety of mechanisms, but a growing body of genetic and biochemical evidence suggests that at least some of these phenomena may be potentiated through mechanisms that require coordinated interaction between the two collagens. For example, genetic studies in humans have identified forms of myopathic Ehlers-Danlos syndrome with overlapping phenotypes that result from mutations in either collagen VI or XII, and biochemical and cell-based studies have identified accessory molecules that could form bridging interactions between the two collagens. However, the demonstration of a direct or ternary structural interaction between collagen VI or XII has not yet been reported. This Hypothesis and Theory review article examines the evidence that supports the existence of a functional complex between type VI and XII collagen in the ECM and discusses potential biological implications.

Comparative analysis of clinical symptoms and biochemical alterations in women with polycystic ovary syndrome: assessing the impact of type 1 diabetes versus non-diabetic controls

BackgroundWomen with type 1 diabetes depend on insulin injections throughout their life. However, the recommendation for strict metabolic control of diabetes requires the administration of supra-physiological doses of insulin, which might result in insulin-mediated stimulation of androgen synthesis. Hyperandrogenism in women with type 1 diabetes may be associated with polycystic ovary syndrome (PCOS). This study was performed to investigate PCOS and its associated clinical symptoms and biochemical alterations in women with type 1 diabetes in the Palestinian Territories. This retrospective cohort study consists of 50 women with type 1 diabetes and 50 apparently healthy non-diabetic controls. Questionnaire interviews were conducted. The diagnosis of PCOS was based on chronic anovulation and biochemical evidence of hyperandrogenism. Serum total testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and insulin were measured by ELISA.ResultsThe mean waist-to-hip ratio and age at menarche were significantly higher in diabetic women than in non-diabetic controls (81.9 ± 7.9 and 13.9 ± 1.6 years vs. 78.8 ± 5.7 and 13.2 ± 1.2 years, and P = 0.045, P = 0.020, respectively). Oligomenorrhea, acanthosis nigricans, seborrhea, and hirsutism were more frequent in diabetics. The levels of total testosterone and insulin were significantly higher in diabetics (0.58 ± 0.11 ng/ml and 15.8 ± 12.4 mlU/ml vs. 0.44 ± 0.11 ng/ml and 10.8 ± 4.5 mlU/ml, P < 0.001 and P = 0.010, respectively). PCOS was present in 11 (22.0%) of diabetic women compared to 3 (6.0%) in non-diabetics (P = 0.044). Diabetic women with PCOS received higher doses of insulin than non-PCOS women (72.7 ± 23.9 vs. 55.0 ± 19.8 UI.cc/ml/day, P = 0.023). PCOS women showed more frequent oligomenorrhea (100% vs. 15.4%, P < 0.001) and higher levels of total testosterone and insulin (0.64 ± 0.09 and 23.1 ± 13.0 vs. 0.53 ± 0.11 and 14.1 ± 11.8, P = 0.023 and P = 0.041, respectively). PCOS cases were significantly more frequent in diabetic women receiving intensive insulin therapy than their counterparts with non-intensive insulin therapy (40.9% vs. 7.1%, P = 0.012).ConclusionIntensive insulin treatment in type 1 diabetes potentiates the development of PCOS and its related clinical and biochemical features particularly oligomenorrhea, hyperinsulinemia, and hyperandrogenemia.

Abstract 5774: Are 19del and L858R really not the same disease entities

Abstract IntroductionThe similarities and differences between the two subtypes of common epidermal growth factor receptor (EGFR) mutations have been recognized by clinicians, but actual treatment strategies remain unchanged. The L858R mutation can be explained by the pharmacological conformational plasticity of the receptor protein and other co-occurring mutations, which may be subtypes of EGFR mutations or non-EGFR mutations, and differences in downstream signaling pathways. As long as we know that molecular differences lead to biological differences, it is a challenge for all of us that our treatment strategies must changeWe investigated the RWD, conformational structure and RNA expression profile about two types of common mutations in the mEGFR+ NSCLC patients.MethodWe collected the medical information for stage I-IIIA mEGFR+ NSCLC patients and explored the conformational structure by crystalized radiologic technique. And we performed RNA expression assay using multiplex IF and High-through-output Profiling. ResultOverall, the static structures of wild type (WT), L858R, and 19del (ΔL747-E749) EGFR did not show any significant differences. However, the difference in the static structure between WT-19del and L858R-19del was subtly greater than that of WT-L858R. In addition, further analyses demonstrated no significant structural differences in the phosphorylation sites. However, it should be noted that proteins do not exist as static structures in vivo, and they have a dynamic, flexible structure that changes over time, i.e., plasticity of proteins. Therefore, we investigated the X-ray B-factor value, which is an indicator of flexibility, dynamics, and plasticity of proteins. As expected, the loop or disordered regions mainly shows higher B-factor values, which indicates an active structure, highly changeable and dynamic. Together, the three types of the EGFR protein manifest wholly similar B-factor values, while several local regions present appreciably distinct B-factors. Physical properties such as the dynamic structure may affect intermolecular recognition of EGFR proteins and their function Recent biochemical and biophysical evidence suggests that oncogenic mutations have an impact on the conformational dynamics of enzymesConclusionIn conclusion, our results suggest that Patients with 19del and L858R mutations demonstrated a different clinical course. It is necessary to consider the dynamic structural characteristics and functional differences of EGFR membrane proteins. Citation Format: Yunseok Heo, Joo Ri Kim, Yeoun Eun Sung, Seoree Kim, Chan Kwon Jung, Jeong-Oh Kim, Jeong-yeon Shin, Guk Jin Lee, Sang hoon Chun, Seong Hyeon Bu, Young Ho Lee, Jin Hyoung Kang. Are 19del and L858R really not the same disease entities [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5774.

Abstract 2655: Unexpected role of the NuRD component, Chd4, in Foxp3+ Treg cells and its relevance to tumor immunotherapy

Abstract We are investigating basic questions like why do Foxp3+ T-regulatory (Treg) cells have at least 3 nuclear complexes involving Hdac1 and Hdac2 (CoREST, Sin3, NuRD), and how can the inhibitory effects of Foxp3+ Tregs on host anti-tumor immune responses be targeted therapeutically? Here, we report on the immune functions of chromodomain-helicase-DNA-binding protein 4 (Chd4), a key enzyme of the nucleosome remodeling and deacetylase complex (NuRD) complex. TCGA analysis showed increased Chd4 expression and Foxp3+ Tregs within lung tumors, leading us to assess the effects of conditional gene deletion within Foxp3+ murine Tregs. Chd4 knockout led to systemic autoimmunity and death of mice within 3 weeks of life and RNAseq studies showed Chd4 loss led to derepression of ~1400 genes and repression of &amp;gt;700 further genes resulting in a Treg signature markedly different from conditional deletion of Hdac1, Hdac2 or Mbd2 in Treg cells. Chd4 is an intrinsically disordered therapeutic target without a defined structure outside its physiological cell environment. To date, no specific inhibitors targeting Chd4 have been developed. We have identified Ch41, a novel and potent inhibitor of Chd4, using a novel cellular target engagement platform. Transcriptomic and mass-spec investigations showed that Ch41 impaired thymic Treg function and iTreg development, led to decreased CNS2 demethylation within the Foxp3 locus, and significantly impaired growth of lung tumors and hepatocellular carcinomas in immunocompetent but not in immunodeficient C57BL/6 mice (p&amp;lt;0.01). Following Chd4 inhibitor therapy, intratumoral conventional T cells had increased activation and cytokine production (IL-2, IFN-g) compared to intratumoral T cells in control tumor-bearing mice but, perhaps unexpectedly, treated mice did not show histologic or biochemical evidence of autoimmunity. We conclude that while tumor associated Tregs have unique properties that include their increased suppressive activity compared to non-tumor associated Treg cells, they are also more susceptible than the latter and conventional T cells to newly developed therapeutic interventions, including targeting of the Chd4 chromodomain of the NuRD complex. Citation Format: Wayne W. Hancock, Liqing Wang, Martina Minisini, Eros di Giorgio, Ivan Babic, Elmar Nurmemmedov. Unexpected role of the NuRD component, Chd4, in Foxp3+ Treg cells and its relevance to tumor immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2655.

Abstract 4807: Gaucher disease treatment reduces the progression of smoldering myeloma

Abstract Background: Gaucher disease (GD), a hereditary condition characterized by glucocerebrosidase deficiency, results in the impaired degradation of glucocerebroside (GL1) and its deacetylated form, lyso-GL1 (LGL1). This leads to the accumulation of these substrates primarily in the bone marrow (BM), liver, and spleen. Notably, individuals with GD face an increased risk of plasma cell dyscrasias (PCD) by approximately nine-fold. We present two compelling cases of the regression of smoldering multiple myeloma (SMM) following GD treatment, substantiated by biochemical evidence of lipid-reactive clonal paraproteins (PP) in both patients. Methods: Peripheral blood samples were obtained with IRB approval from patients with concurrent SMM and GD at the Icahn School of Medicine at Mount Sinai. Utilizing C-18 beads coupled with gly-sphingosine-coated liposomes and Sphingosine-1 phosphate bead liposome-based pulldown, we established the binding of glycolipids to serum PP. Results: In a 66-year-old male, hepatosplenomegaly and pancytopenia revealed compound heterozygous N370S/V394L mutations and reduced β-glucosidase activity, confirming Type 1 GD. Laboratory findings included substantial pancytopenia (WBC 2.5 k/µL, Hgb 12.1 g/dL, platelet 44 k/µL) and myeloma markers (M spike 1.58 g/dL, monoclonal IgA λ). A BM biopsy indicated 30% λ-restricted plasma cells. PET-CT showed hepatosplenomegaly without FDG avid lytic lesions, consistent with SMM. Imiglucerase enzyme therapy improved GD biomarkers, decreased hepatosplenomegaly, and blood count improvement (WBC 4.7 k/µL, Hgb 13.6 g/dL, platelet 66 k/µL). Notably, myeloma burden significantly reduced (M-spike 0.94 g/dL, IgA 1373 g/dL and free lambda 26.1 mg/L). Similarly, a 41-year-old female with mild fatigue, Hgb levels of 10.9 g/dL, a platelet count of 169 k/µL, M spike of 0.9 g/dL, IgG κappa on immunofixation, and IgG levels at 1730 mg/dL, indicating SMM. GBA analysis showed homozygous N370S mutation and reduced beta-glucosidase activity consistent with Type 1 GD. Substrate reduction therapy with eliglustat alleviated fatigue, reduced GD biomarkers, normalized cytopenias, and gradually decreased myeloma markers. Laboratory results indicated an M spike of 0.5 g/dL, IgG levels at 1295 mg/dL, and free kappa at 31.3 mg/L. To explore the interaction between clonal immunoglobulins (Ig) and lyso-lipids, we utilized Gly-sphingolipids (see methods) and demonstrated a robust interaction with IgA (patient 1) and IgG (patient 2) paraprotein by western blotting. Conclusion: Our experimental findings confirm specific clonal Ig binding in SMM and GD patients and demonstrate potent and timely benefits from addressing GD in managing SMM patients. This holds significance amid ongoing clinical trials exploring aggressive interventions for SMM, including bispecific and CAR-T therapies. Citation Format: Ravi Prakash Shukla, Anshuman Parekh, Violetta V Leshchenko, Kevin Barley, Deepa Vatti, Daniel Verina, Manisha Balwani, Samir Parekh. Gaucher disease treatment reduces the progression of smoldering myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4807.

Effects of Hypoxia and Reoxygenation on Metabolic Profiles of Cardiomyocytes.

In vitro cellular models provide valuable insights into the adaptive biochemical mechanisms triggered by cells to cope with the stress situation induced by hypoxia and reoxygenation cycles. The first biological data generated in studies based on this micrometric life-scale has the potential to provide us a global overview about the main biochemical phenomena presented in some reported preconditioning therapies in life-scale of higher dimensions. Thus, in this study, a cell incubator was designed and manufactured to produce a cellular model of heart hypoxia followed by reoxygenation (HfR) through consecutive repetitions of hypoxia-normoxia gas exchange. Samples of cellular extracts and culture media were obtained from non-proliferative cardiomyocytes (CMs) cultivated under challenging HfR (stressed CMs) and regular cultivation (unstressed CMs) in rounds of four days for each case. Metabolomic based on proton magnetic resonance spectroscopy (1H-MRS) was used as an analytical approach to identify and quantify the metabolomes of these samples, the endo- and exo-metabolome. Despite the stressed CMs presented over 90% higher cellular death rate compared to the unstressed CMs, the metabolic profiles indicates that the surviving cells up-regulate their amino acid metabolism either by active protein degradation or by the consumption of culture media components to increase coenzyme A-dependent metabolic pathways. This cell auto-regulation mechanism could be well characterized in the first two days when the difference smears off under once the metabolomes become similar. The metabolic adaptations of stressed CMs identified the relevance of the cyclic oxidation/reduction reactions of nicotinamide adenine dinucleotide phosphate molecules, NADP+/NADPH, and the increased tricarboxylic acid cycle activity in an environment overloaded with such a powerful antioxidant agent to survive an extreme HfR challenge. Thus, the combination of cellular models based on CMs, investigative methods, such as metabolomic and 1H-MRS, and the instrumental development of hypoxia incubator shown in this work were able to provide the first biochemical evidences behind therapies of gaseous exchanges paving the way to future assays.

8-OxoG-Dependent Regulation of Global Protein Responses Leads to Mutagenesis and Stress Survival in Bacillus subtilis.

The guanine oxidized (GO) system of Bacillus subtilis, composed of the YtkD (MutT), MutM and MutY proteins, counteracts the cytotoxic and genotoxic effects of the oxidized nucleobase 8-OxoG. Here, we report that in growing B. subtilis cells, the genetic inactivation of GO system potentiated mutagenesis (HPM), and subsequent hyperresistance, contributes to the damaging effects of hydrogen peroxide (H2O2) (HPHR). The mechanism(s) that connect the accumulation of the mutagenic lesion 8-OxoG with the ability of B. subtilis to evolve and survive the noxious effects of oxidative stress were dissected. Genetic and biochemical evidence indicated that the synthesis of KatA was exacerbated, in a PerR-independent manner, and the transcriptional coupling repair factor, Mfd, contributed to HPHR and HPM of the ΔGO strain. Moreover, these phenotypes are associated with wider pleiotropic effects, as revealed by a global proteome analysis. The inactivation of the GO system results in the upregulated production of KatA, and it reprograms the synthesis of the proteins involved in distinct types of cellular stress; this has a direct impact on (i) cysteine catabolism, (ii) the synthesis of iron-sulfur clusters, (iii) the reorganization of cell wall architecture, (iv) the activation of AhpC/AhpF-independent organic peroxide resistance, and (v) increased resistance to transcription-acting antibiotics. Therefore, to contend with the cytotoxic and genotoxic effects derived from the accumulation of 8-OxoG, B. subtilis activates the synthesis of proteins belonging to transcriptional regulons that respond to a wide, diverse range of cell stressors.

Enucleation of a solitary pancreatic tail insulinoma: a case report and review of the literature

Introduction: Insulinomas are the most common pancreatic neuroendocrine tumors. They secrete insulin and result in endogenous hyperinsulinaemic hypoglycemia. The diagnosis of insulinoma was classically based on the fulfillment of Whipple’s triad; hypoglycaemia (plasma glucose &lt;50mg/dL), neuroglycopaenic symptoms, and the prompt relief of such symptoms with the administration of glucose. Preoperative localization of the insulinoma will help to plan the type of surgery necessary, either enucleation or pancreatic resection, and also decide on the approach, either open or laparoscopic. Case description: A 53-year-old farmer presented with neuroglycopenia symptoms with biochemical evidence of endogenous hyperinsulinaemic hypoglycemia during the mixed meal test. Imaging evidence in the form of CT and MRI showed a benign, approximately 1cm, solitary pancreatic tail insulinoma. Intraoperative ultrasonography confirmed the findings and the patient underwent enucleation of the tumor. Histology revealed a grade 2 pancreatic neuroendocrine tumor with confirmation of an insulinoma on immunohistochemistry. Conclusion: Pancreatic insulinomas, a rare pancreatic tumor, the commonest of the pNET present with neuroglycopenia. Diagnosis entails biochemical confirmation of endogenous hyperinsulinaemic hypoglycemia on a 72-hour prolonged fasting test. Noninvasive imaging in the form of CT as the first line, followed by MRI is used for localization and assessment of resectability. EUS and ASVS are additional invasive imaging in diagnostic difficulty. Enucleation and intraoperative ultrasonography is the treatment of choice for small, benign, pancreatic insulinomas.

Interactions between Gepotidacin and Escherichia coli Gyrase and Topoisomerase IV: Genetic and Biochemical Evidence for Well-Balanced Dual-Targeting.

Antimicrobial resistance is a global threat to human health. Therefore, efforts have been made to develop new antibacterial agents that address this critical medical issue. Gepotidacin is a novel, bactericidal, first-in-class triazaacenaphthylene antibacterial in clinical development. Recently, phase III clinical trials for gepotidacin treatment of uncomplicated urinary tract infections caused by uropathogens, including Escherichia coli, were stopped for demonstrated efficacy. Because of the clinical promise of gepotidacin, it is important to understand how the compound interacts with its cellular targets, gyrase and topoisomerase IV, from E. coli. Consequently, we determined how gyrase and topoisomerase IV mutations in amino acid residues that are involved in gepotidacin interactions affect the susceptibility of E. coli cells to the compound and characterized the effects of gepotidacin on the activities of purified wild-type and mutant gyrase and topoisomerase IV. Gepotidacin displayed well-balanced dual-targeting of gyrase and topoisomerase IV in E. coli cells, which was reflected in a similar inhibition of the catalytic activities of these enzymes by the compound. Gepotidacin induced gyrase/topoisomerase IV-mediated single-stranded, but not double-stranded, DNA breaks. Mutations in GyrA and ParC amino acid residues that interact with gepotidacin altered the activity of the compound against the enzymes and, when present in both gyrase and topoisomerase IV, reduced the antibacterial activity of gepotidacin against this mutant strain. Our studies provide insights regarding the well-balanced dual-targeting of gyrase and topoisomerase IV by gepotidacin in E. coli.

Discovery of Red-Shifting Mutations in Firefly Luciferase Using High-Throughput Biochemistry.

Photinus pyralis luciferase (FLuc) has proven a valuable tool for bioluminescence imaging, but much of the light emitted from the native enzyme is absorbed by endogenous biomolecules. Thus, luciferases displaying red-shifted emission enable higher resolution during deep-tissue imaging. A robust model of how protein structure determines emission color would greatly aid the engineering of red-shifted mutants, but no consensus has been reached to date. In this work, we applied deep mutational scanning to systematically assess 20 functionally important amino acid positions on FLuc for red-shifting mutations, predicting that an unbiased approach would enable novel contributions to this debate. We report dozens of red-shifting mutations as a result, a large majority of which have not been previously identified. Further characterization revealed that mutations N229T and T352M, in particular, bring about unimodal emission with the majority of photons being >600 nm. The red-shifting mutations identified by this high-throughput approach provide strong biochemical evidence for the multiple-emitter mechanism of color determination and point to the importance of a water network in the enzyme binding pocket for altering the emitter ratio. This work provides a broadly applicable mutational data set tying FLuc structure to emission color that contributes to our mechanistic understanding of emission color determination and should facilitate further engineering of improved probes for deep-tissue imaging.

Haemoglobin thresholds to define anaemia from age 6 months to 65 years: estimates from international data sources

Detection of anaemia is crucial for clinical medicine and public health. Current WHO anaemia definitions are based on statistical thresholds (fifth centiles) set more than 50 years ago. We sought to establish evidence for the statistical haemoglobin thresholds for anaemia that can be applied globally and inform WHO and clinical guidelines. In this analysis we identified international data sources from populations in the USA, England, Australia, China, the Netherlands, Canada, Ecuador, and Bangladesh with sufficient clinical and laboratory information collected between 1998 and 2020 to obtain a healthy reference sample. Individuals with clinical or biochemical evidence of a condition that could reduce haemoglobin concentrations were excluded. We estimated haemoglobin thresholds (ie, 5th centiles) for children aged 6-23 months, 24-59 months, 5-11 years, and 12-17 years, and adults aged 18-65 years (including during pregnancy) for individual datasets and pooled across data sources. We also collated findings from three large-scale genetic studies to summarise genetic variants affecting haemoglobin concentrations in different ancestral populations. We identified eight data sources comprising 18 individual datasets that were eligible for inclusion in the analysis. In pooled analyses, the haemoglobin fifth centile was 104·4 g/L (90% CI 103·5-105·3) in 924 children aged 6-23 months, 110·2 g/L (109·5-110·9) in 1874 children aged 24-59 months, and 114·4 g/L (113·6-115·2) in 1839 children aged 5-11 years. Values diverged by sex in adolescents and adults. In pooled analyses, the fifth centile was 122·2 g/L (90% CI 121·3-123·1) in 1741 female adolescents aged 12-17 years and 128·2 g/L (126·4-130·0) in 1103 male adolescents aged 12-17 years. In pooled analyses of adults aged 18-65 years, the fifth centile was 119·7 g/L (90% CI 119·1-120·3) in 3640 non-pregnant females and 134·9 g/L (134·2-135·6) in 2377 males. Fifth centiles in pregnancy were 110·3 g/L (90% CI 109·5-111·0) in the first trimester (n=772) and 105·9 g/L (104·0-107·7) in the second trimester (n=111), with insufficient data for analysis in the third trimester. There were insufficient data for adults older than 65 years. We did not identify ancestry-specific high prevalence of non-clinically relevant genetic variants that influence haemoglobin concentrations. Our results enable global harmonisation of clinical and public health haemoglobin thresholds for diagnosis of anaemia. Haemoglobin thresholds are similar between sexes until adolescence, after which males have higher thresholds than females. We did not find any evidence that thresholds should differ between people of differering ancestries. World Health Organization and the Bill & Melinda Gates Foundation.

Vitamin deficiencies in children: Lessons from clinical and neuroimaging findings

Background and aimsWater-soluble vitamins play an essential coenzyme role in the nervous system. Acquired vitamin deficiencies are easily treatable, however, without treatment, they can lead to irreversible complications. This study aimed to provide clinical, laboratory parameters and neuroimaging data on vitamin deficiencies in an attempt to facilitate early diagnosis and prompt supplementation. MethodsFrom July 1998 to July 2023, patients at Necker-Enfants-Malades Hospital presenting with acute neurological symptoms attributed to acquired vitamin deficiency were included. Clinical data were extracted from Dr Warehouse database. Neuroimaging, biochemical and electrophysiological data were reviewed. ResultsPatients with vitamin B1 deficiency exhibited abnormal eye movements (n = 4/4), fluctuations in consciousness (n = 3/4), and ataxia (n = 3/4). Brain MRI showed alterations of fourth ventricle region (n = 4/4), periaqueductal region (n = 4/4), tectum (n = 3/4), and median thalami (n = 3/4). Patients with vitamin B2 deficiency presented with early onset hypotonia (n = 3/4), hyperlactatemia (n = 4/4), and hyperammonemia (n = 4/4). Plasma acylcarnitines revealed a multiple acyl-coA dehydrogenase deficiency-like profile (n = 4/4). In vitamin B12 deficiency, young children presented with developmental delay (n = 7/7) and older children with proprioceptive ataxia (n = 3/3). Brain MRI revealed atrophy (n = 7/7) and spinal MRI hyperintensity in posterior cervical columns (n = 3/3). Metabolic findings showed elevated methylmalonic acid (n = 6/7) and hyperhomocysteinemia (n = 6/7). Patients with vitamin C deficiency exhibited gait disturbances and muscle weakness (n = 2/2). ConclusionsAcquired vitamin deficiencies may display reversible clinical symptoms mimicking inherited metabolic disorders. Some situations raise suspicion for diagnosis: concordant clinical presentation, suggestive neuroimaging findings, and/or biochemical evidence. Any acute neurological condition should be treated without waiting for definitive biochemical confirmation.

Biochemical evidence for conformational variants in the anti-viral and pro-metastatic protein IFITM1.

Interferon induced transmembrane proteins (IFITMs) play a dual role in the restriction of RNA viruses and in cancer progression, yet the mechanism of their action remains unknown. Currently, there is no data about the basic biochemical features or biophysical properties of the IFITM1 protein. In this work, we report on description and biochemical characterization of three conformational variants/oligomeric species of recombinant IFITM1 protein derived from an Escherichia coli expression system. The protein was extracted from the membrane fraction, affinity purified, and separated by size exclusion chromatography where two distinct oligomeric species were observed in addition to the expected monomer. These species remained stable upon re-chromatography and were designated as "dimer" and "oligomer" according to their estimated molecular weight. The dimer was found to be less stable compared to the oligomer using circular dichroism thermal denaturation and incubation with a reducing agent. A two-site ELISA and HDX mass spectrometry suggested the existence of structural motif within the N-terminal part of IFITM1 which might be significant in oligomer formation. Together, these data show the unusual propensity of recombinant IFITM1 to naturally assemble into very stable oligomeric species whose study might shed light on IFITM1 anti-viral and pro-oncogenic functions in cells.

Management of Adolescent PCOD: A Real Challenge

Background: Polycystic Ovary Syndrome (PCOS) is a common hormonal disorder affecting 5-10% of women worldwide, characterized by irregular menstrual cycles and cysts on the ovaries. Its exact cause is unknown, but early identification and intervention can reduce the risk of complications like diabetes and heart disease. PCOS manifests in various ways, impacting reproductive, cosmetic, metabolic, and psychological aspects. Prevalence is higher in certain ethnic groups, and diagnosis can occur in adolescence but is often delayed. Despite its global impact, most studies focus on developed countries. Aim of the study: The study aims to explore the diagnosis and treatment procedures for managing adolescent PCOD in Bangladesh. Methods: This study, conducted at the Holly lab hospital &amp;Missionary Hospital Brahmanbaria, Bangladesh. The study spanned one year from January 2023 to December 2023. Diagnosis relied on clinical and biochemical evidence of hyperandrogenism and persistent menstrual irregularities. A one-on-one interview gathered comprehensive medical information. Inclusion criteria covered females aged 10 to 19, while exclusions involved specific medical conditions and ongoing treatments. Statistical analyses using SPSS included expressing variables and logistic regression to identify metabolic syndrome risk factors. The significance level was set at p ≤ 0.05 for statistical relevance. Result: The study involves 107 adolescent participants with Polycystic Ovary Syndrome (PCOD). Most were aged 10-15 (55.14%) with an average age of 16.8. BMI analysis showed high prevalence of overweight (29.70%) and obesity (39.40%). Abdominal obesity was normal in 76.60%, while 20.00% were pre-hypertensive, and 3.40% had hypertension. Glycemic status varied, with 76.00% normoglycemic, 21.10% prediabetic, and 2.90% diabetic. Dyslipidemia was present in 90.90%, and metabolic syndrome in 42.30%. Biochemical hyperandrogenism was observed in 33.70%. PCOD features included hirsutism (94.90%) and menstrual irregularities (oligomenorrhea 87.85%). Ovarian morphology showed diverse patterns. Hyperandrogenism, ovulatory dysfunction, ovarian morphology, and metabolic factors were primary contributors to PCOD diagnosis. Treatment approaches varied, including classical interventions (34.58%), lifestyle changes (14.95%), combined oral contraception (12.15%), and antiandrogens (7.48%). Therapeutic treatments included N-acetylcysteine, Inositol, Vitamin D supplementation, and Chromium supplementation. Conclusion: Managing adolescent Polycystic Ovary Syndrome (PCOS) is challenging due to the high prevalence of metabolic complications. Diagnostic complexity emphasizes careful evaluation to prevent premature labelling and psychological stress. Treatment involves lifestyle interventions, hormonal contraceptives, and anti-androgen medications. Standardized diagnostic criteria and a multidisciplinary approach are crucial. Early intervention and continuous monitoring are essential for mitigating long-term health risks. Further research on PCOS in diverse populations is recommended for tailored interventions and a nuanced understanding.