A bioluminescent and homogeneous assay for monitoring GPCR-mediated cAMP modulation and PDE activity

3',5'-Cyclic adenosine monophosphate (cAMP), the first identified second messenger, is implicated in diverse cellular processes involving cellular metabolism, cell proliferation and differentiation, apoptosis, and gene expression. cAMP is synthesized by adenylyl cyclase (AC), which converts ATP to cAMP upon activation of Gαs-protein coupled receptors (GPCRs) in most cases and hydrolyzed by cyclic nucleotide phosphodiesterases (PDEs) to 5'-AMP. Dysregulation of cAMP signaling is implicated in a wide range of pathophysiological conditions such as cardiovascular diseases, neurodegenerative and behavioral disorders, cancers, diabetes, obesity, cataracts, and others. Therefore, cAMP targeted therapies have been and are still undergoing intense investigation for the treatment of these and other diseases. This highlights the need for developing assays to detect and monitor cAMP levels. In this study, we show cAMP Lumit assay as a highly specific homogeneous bioluminescent assay suitable for high throughput screenings with a large assay window and a wide dynamic range for cAMP detection. We believe that this assay will aid and simplify drug discovery screening efforts for cAMP signaling targeted therapies.

Aim18p and Aim46p are chalcone isomerase domain-containing mitochondrial hemoproteins in Saccharomyces cerevisiae

Chalcone isomerases (CHIs) have well-established roles in the biosynthesis of plant flavonoid metabolites. Saccharomyces cerevisiae possesses two predicted CHI-like proteins, Aim18p (encoded by YHR198C) and Aim46p (YHR199C), but it lacks other enzymes of the flavonoid pathway, suggesting that Aim18p and Aim46p employ the CHI fold for distinct purposes. Here, we demonstrate using proteinase K protection assays, sodium carbonate extractions, and crystallography that Aim18p and Aim46p reside on the mitochondrial inner membrane and adopt CHI folds, but they lack select active site residues and possess an extra fungal-specific loop. Consistent with these differences, Aim18p and Aim46p lack CHI activity and also the fatty acid-binding capabilities of other CHI-like proteins, but instead bind heme. We further show that diverse fungal homologs also bind heme and that Aim18p and Aim46p possess structural homology to a bacterial hemoprotein. Collectively, our work reveals a distinct function and cellular localization for two CHI-like proteins, introduces a new variation of a hemoprotein fold, and suggests that ancestral CHI-like proteins were hemoproteins.

2-Propylphenol Allosterically Modulates COQ8A to Enhance ATPase Activity

COQ8A is an atypical kinase-like protein that aids the biosynthesis of coenzyme Q, an essential cellular cofactor and antioxidant. COQ8A's mode of action remains unclear, in part due to the lack of small molecule tools to probe its function. Here, we blend NMR and hydrogen-deuterium exchange mass spectrometry to help determine how a small CoQ precursor mimetic, 2-propylphenol, modulates COQ8A activity. We identify a likely 2-propylphenol binding site and reveal that this compound modulates a conserved COQ8A domain to increase nucleotide affinity and ATPase activity. Our findings promise to aid further investigations into COQ8A's precise enzymatic function and the design of compounds capable of boosting endogenous CoQ production for therapeutic gain.

Clinico-Genetic, Imaging and Molecular Delineation of COQ8A-Ataxia: A Multicenter Study of 59 Patients

OBJECTIVE

To foster trial-readiness of coenzyme Q8A (COQ8A)-ataxia, we map the clinicogenetic, molecular, and neuroimaging spectrum of COQ8A-ataxia in a large worldwide cohort, and provide first progression data, including treatment response to coenzyme Q10 (CoQ10).

METHODS

Cross-modal analysis of a multicenter cohort of 59 COQ8A patients, including genotype-phenotype correlations, 3D-protein modeling, in vitro mutation analyses, magnetic resonance imaging (MRI) markers, disease progression, and CoQ10 response data.

RESULTS

Fifty-nine patients (39 novel) with 44 pathogenic COQ8A variants (18 novel) were identified. Missense variants demonstrated a pleiotropic range of detrimental effects upon protein modeling and in vitro analysis of purified variants. COQ8A-ataxia presented as variable multisystemic, early-onset cerebellar ataxia, with complicating features ranging from epilepsy (32%) and cognitive impairment (49%) to exercise intolerance (25%) and hyperkinetic movement disorders (41%), including dystonia and myoclonus as presenting symptoms. Multisystemic involvement was more prevalent in missense than biallelic loss-of-function variants (82-93% vs 53%; p = 0.029). Cerebellar atrophy was universal on MRI (100%), with cerebral atrophy or dentate and pontine T2 hyperintensities observed in 28%. Cross-sectional (n = 34) and longitudinal (n = 7) assessments consistently indicated mild-to-moderate progression of ataxia (SARA: 0.45/year). CoQ10 treatment led to improvement by clinical report in 14 of 30 patients, and by quantitative longitudinal assessments in 8 of 11 patients (SARA: -0.81/year). Explorative sample size calculations indicate that ≥48 patients per arm may suffice to demonstrate efficacy for interventions that reduce progression by 50%.

INTERPRETATION

This study provides a deeper understanding of the disease, and paves the way toward large-scale natural history studies and treatment trials in COQ8A-ataxia. ANN NEUROL 2020;88:251-263.

Clinico-Genetic, Imaging and Molecular Delineation of COQ8A-Ataxia: A Multicenter Study of 59 Patients

OBJECTIVE

To foster trial-readiness of coenzyme Q8A (COQ8A)-ataxia, we map the clinicogenetic, molecular, and neuroimaging spectrum of COQ8A-ataxia in a large worldwide cohort, and provide first progression data, including treatment response to coenzyme Q10 (CoQ10).

METHODS

Cross-modal analysis of a multicenter cohort of 59 COQ8A patients, including genotype-phenotype correlations, 3D-protein modeling, in vitro mutation analyses, magnetic resonance imaging (MRI) markers, disease progression, and CoQ10 response data.

RESULTS

Fifty-nine patients (39 novel) with 44 pathogenic COQ8A variants (18 novel) were identified. Missense variants demonstrated a pleiotropic range of detrimental effects upon protein modeling and in vitro analysis of purified variants. COQ8A-ataxia presented as variable multisystemic, early-onset cerebellar ataxia, with complicating features ranging from epilepsy (32%) and cognitive impairment (49%) to exercise intolerance (25%) and hyperkinetic movement disorders (41%), including dystonia and myoclonus as presenting symptoms. Multisystemic involvement was more prevalent in missense than biallelic loss-of-function variants (82-93% vs 53%; p = 0.029). Cerebellar atrophy was universal on MRI (100%), with cerebral atrophy or dentate and pontine T2 hyperintensities observed in 28%. Cross-sectional (n = 34) and longitudinal (n = 7) assessments consistently indicated mild-to-moderate progression of ataxia (SARA: 0.45/year). CoQ10 treatment led to improvement by clinical report in 14 of 30 patients, and by quantitative longitudinal assessments in 8 of 11 patients (SARA: -0.81/year). Explorative sample size calculations indicate that ≥48 patients per arm may suffice to demonstrate efficacy for interventions that reduce progression by 50%.

INTERPRETATION

This study provides a deeper understanding of the disease, and paves the way toward large-scale natural history studies and treatment trials in COQ8A-ataxia. ANN NEUROL 2020;88:251-263.

Clinico-Genetic, Imaging and Molecular Delineation of COQ8A-Ataxia: A Multicenter Study of 59 Patients

OBJECTIVE

To foster trial-readiness of coenzyme Q8A (COQ8A)-ataxia, we map the clinicogenetic, molecular, and neuroimaging spectrum of COQ8A-ataxia in a large worldwide cohort, and provide first progression data, including treatment response to coenzyme Q10 (CoQ10).

METHODS

Cross-modal analysis of a multicenter cohort of 59 COQ8A patients, including genotype-phenotype correlations, 3D-protein modeling, in vitro mutation analyses, magnetic resonance imaging (MRI) markers, disease progression, and CoQ10 response data.

RESULTS

Fifty-nine patients (39 novel) with 44 pathogenic COQ8A variants (18 novel) were identified. Missense variants demonstrated a pleiotropic range of detrimental effects upon protein modeling and in vitro analysis of purified variants. COQ8A-ataxia presented as variable multisystemic, early-onset cerebellar ataxia, with complicating features ranging from epilepsy (32%) and cognitive impairment (49%) to exercise intolerance (25%) and hyperkinetic movement disorders (41%), including dystonia and myoclonus as presenting symptoms. Multisystemic involvement was more prevalent in missense than biallelic loss-of-function variants (82-93% vs 53%; p = 0.029). Cerebellar atrophy was universal on MRI (100%), with cerebral atrophy or dentate and pontine T2 hyperintensities observed in 28%. Cross-sectional (n = 34) and longitudinal (n = 7) assessments consistently indicated mild-to-moderate progression of ataxia (SARA: 0.45/year). CoQ10 treatment led to improvement by clinical report in 14 of 30 patients, and by quantitative longitudinal assessments in 8 of 11 patients (SARA: -0.81/year). Explorative sample size calculations indicate that ≥48 patients per arm may suffice to demonstrate efficacy for interventions that reduce progression by 50%.

INTERPRETATION

This study provides a deeper understanding of the disease, and paves the way toward large-scale natural history studies and treatment trials in COQ8A-ataxia. ANN NEUROL 2020;88:251-263.

Crystal structure of the WFIKKN2 follistatin domain reveals insight into how it inhibits growth differentiation factor 8 (GDF8) and GDF11

Growth differentiation factor 8 (GDF8; also known as myostatin) and GDF11 are closely related members of the transforming growth factor β (TGF-β) family. GDF8 strongly and negatively regulates skeletal muscle growth, and GDF11 has been implicated in various age-related pathologies such as cardiac hypertrophy. GDF8 and GDF11 signaling activities are controlled by the extracellular protein antagonists follistatin; follistatin-like 3 (FSTL3); and WAP, follistatin/kazal, immunoglobulin, Kunitz, and netrin domain-containing (WFIKKN). All of these proteins contain a follistatin domain (FSD) important for ligand binding and antagonism. Here, we investigated the structure and function of the FSD from murine WFIKKN2 and compared it with the FSDs of follistatin and FSTL3. Using native gel shift and surface plasmon resonance analyses, we determined that the WFIKKN2 FSD can interact with both GDF8 and GDF11 and block their interactions with the type II receptor activin A receptor type 2B (ActRIIB). Further, we solved the crystal structure of the WFIKKN2 FSD to 1.39 Å resolution and identified surface-exposed residues that, when substituted with alanine, reduce antagonism of GDF8 in full-length WFIKKN2. Comparison of the WFIKKN2 FSD with those of follistatin and FSTL3 revealed differences in both the FSD structure and position of residues within the domain that are important for ligand antagonism. Taken together, our results indicate that both WFIKKN and follistatin utilize their FSDs to block the type II receptor but do so via different binding interactions.

Crystal structure of [propane-1,3-diylbis(piperidine-4,1-diyl)]bis[(pyridin-4-yl)methanone]–isophthalic acid (1/1)

In the co-crystal of isophthalic acid and [propane-1,3-diylbis(piperidine-4,1-di­yl)]bis­[(pyridin-4-yl)methanone], mol­ecules are connected into supra­molecular chains aligned along the c axis by O—H⋯N hydrogen bonding. These aggregate into supra­molecular layers oriented parallel to the ac plane by C—H⋯O inter­actions.

In the crystal structure of the title co-crystal, C₂₅H₃₂N₄O₂·C₈H₆O₄, isophthalic acid and [propane-1,3-diylbis(piperidine-4,1-di­yl)]bis­(pyridin-4-yl­methanone) mol­ecules are connected into supra­molecular chains aligned along the c axis by O—H⋯N hydrogen bonding. These aggregate into supra­molecular layers oriented parallel to the ac plane by C—H⋯O inter­actions. These layers then stack in an ABCD pattern along the b-axis direction by additional C—H⋯O inter­actions to give the full three-dimensional crystal structure. The central chain in the di­pyridyl­amide molecule has an anti–gauche conformation.

Review of international safety data for lisinopril-hydrochlorothiazide combination treatment

A total of 930 patients have been evaluated for safety in a programme of clinical trials for lisinopril-hydrochlorothiazide combination treatment. Combination therapy with these two agents is generally well tolerated. In clinical trials, adverse experiences in patients treated with a lisinopril-hydrochlorothiazide combination were dizziness (7.5%), headache (5.2%), cough (3.9%), fatigue (3.7%), orthostatic effects (3.2%), diarrhoea (2.5%), nausea (2.2%) and upper respiratory tract infection (2.2%). Withdrawals from treatment have been relatively infrequent comprising dizziness (0.8%), headache (0.3%), cough (0.6%), fatigue (0.4%), diarrhoea (0.2%), orthostatic effects and nausea (0.1% each). The most common laboratory adverse experiences in patients on therapy with the lisinopril-hydrochlorothiazide combination are: increases in serum glucose, triglycerides, uric acid, serum creatinine, blood urea nitrogen and blood urea; and decreases in serum potassium. However, in individual controlled studies, the addition of lisinopril to treatment with hydrochlorothiazide results in attenuation of some of the potentially adverse metabolic affects of the diuretic. Adverse experiences in the patients treated for periods of 50 weeks or more, the elderly and the renally impaired are similar to those seen in the total population. Overall the available data indicate that a fixed dose combination of lisinopril-hydrochlorothiazide is a well-tolerated therapeutic option in patients with mild-to-moderate hypertension.

Duration of angiotensin-converting enzyme inhibition: implications for tolerability

A large co-ordinated multinational clinical-trial programme in hypertension has provided comparative data on adverse events in patients on lisinopril (n = 318) compared with enalapril (n = 321) and in 230 patients on lisinopril versus captopril (n = 235). The three groups were demographically well matched with regard to age and duration of treatment. However, in comparison with the lisinopril group, the captopril-treated group had a slightly higher proportion of males (NS). The incidence of adverse events on lisinopril was similar to that on enalapril (10.4 vs. 8.7%, NS) and captopril (11.7 vs. 11.9%, NS). The incidence of withdrawals was similar on lisinopril and enalapril (1.9 vs. 1.9%, NS) and captopril (4.8 vs. 3.0%, NS). The most frequently reported events affected the digestive, respiratory, or nervous and psychiatric systems of the body. The pattern of events and withdrawals was similar for all three drugs. The incidence of laboratory changes for lisinopril versus enalapril and lisinopril versus captopril was similar. The safety profiles of all three drugs were comparable in young and elderly patients. First-dose hypotension was reported for 2 of 548 patients on lisinopril, and renal failure was reported for 3 of 286 patients on enalapril. Overall, the events reflected the class-specific effects previously identified for angiotensin-converting enzyme inhibitors. The data indicate that long-acting angiotensin-converting enzyme inhibitors do not impose any additional side-effect risk in hypertension.

Traumatic left ventricular aneurysm: report of a case with normal coronary arteries

A 26-year-old male had an anterior myocardial infarction following blunt chest trauma. He developed a left ventricular aneurysm despite coronary angiography being normal.

Modern cardiac pacing: the role of dual chamber systems

Atrial synchronous or dual chamber pacemakers are at the forefront of current pacing technology. This article discusses the mechanisms of dual chamber pacing and considers the role of such systems in modern clinical practice.

Day case cardiac catheterisation using the Sones technique

Cardiac catheterisation using the Sones technique was planned as a day case procedure in 855 of 1662 consecutive patients admitted for cardiac catheterisation. Of these, 810 (95%) were discharged the same day. Forty-five (5%) needed overnight hospitalization, 34 for reasons connected with the procedure and 11 for other reasons. No serious complications occurred and there were no deaths. The cost of day stay was approximately half that incurred using overnight stay. Thus, cardiac catheterisation using the Sones technique on a day case basis is safe and may produce significant cost efficiency.

Echocardiographic demonstration of Escherichia coli endocarditis restricted to the pulmonary valve

A 25 year old man with no history of heart disease presented with sweats and rigors. Echocardiography showed a large vegetation on the pulmonary valve and blood cultures grew Escherichia coli. Because of recurrent pulmonary emboli a large vegetation on the anterior leaflet of the pulmonary valve was excised. He recovered after a full course of antibiotics.

Thrombolysis for myocardial infarction

Treating myocardial infarction by dissolving occlusive thrombi in coronary arteries is an attractive idea. Although some thrombolytic agents have been available for many years their use in this role has only recently been critically examined. The place of thrombolysis in the management of myocardial infarction has yet to be determined.

Recurrent rheumatic fever

Although recurrent rheumatic fever in adults is uncommon and the recurrence rate declines with age and with the interval from the attack, we describe a patient who has had four attacks of rheumatic fever, two in childhood and two in adult life.