Aim
We evaluated the efficacy and safety of ertugliflozin, an SGLT2 inhibitor, in type 2 diabetes mellitus (T2DM) inadequately controlled (HbA1c, 7.0%‐10.5%) with metformin monotherapy (≥1500 mg/d ...for ≥8 weeks).
Methods
This was a double‐blind, 26‐week, multicentre study with ongoing 78‐week extension (ClinicalTrials.gov identifier: NCT02033889). A total of 621 participants were randomized 1:1:1 to placebo, or ertugliflozin 5 or 15 mg/d. The primary endpoint was change from baseline at week 26 in HbA1c. Secondary efficacy endpoints were change from baseline at week 26 in fasting plasma glucose (FPG), body weight, systolic/diastolic blood pressure (SBP/DBP) and number of participants with HbA1c <7.0% (53 mmol/mol). Pre‐specified adverse events (AEs) of special interest and percent change from baseline in bone mineral density (BMD) were also assessed at week 26.
Results
At week 26, the placebo‐adjusted least‐squares mean change from baseline HbA1c (8.1%) was −0.7% and −0.9% for ertugliflozin 5 and 15 mg, respectively (both P < .001), to final means of 7.3% and 7.2%, respectively. The odds of HbA1c <7.0% were significantly greater in both ertugliflozin groups vs placebo. Ertugliflozin significantly reduced FPG, body weight, SBP and DBP vs placebo. The incidence of genital mycotic infections was higher in the ertugliflozin groups (female subjects: placebo, 0.9%; ertugliflozin 5 mg, 5.5%; ertugliflozin 15 mg, 6.3% P = .032; male subjects: 0%; 3.1%; 3.2%, respectively), as was the incidence of urinary tract infections and symptomatic hypoglycaemia. The incidence of hypovolaemia AEs was similar across groups. Ertugliflozin had no adverse impact on BMD at week 26.
Conclusions
Ertugliflozin added to metformin in patients with inadequately controlled T2DM improved glycaemic control, reduced body weight and BP, but increased the incidence of genital mycotic infections.
Mutations in the AAA adenosine triphosphatase (ATPase) Spastin (SPG4) cause an autosomal dominant form of hereditary spastic paraplegia, which is a retrograde axonopathy primarily characterized ...pathologically by the degeneration of long spinal neurons in the corticospinal tracts and the dorsal columns. Using recombinant Spastin, we find that six mutant forms of Spastin, including three disease-associated forms, are severely impaired in ATPase activity. In contrast to a mutation designed to prevent adenosine triphosphate (ATP) binding, an ATP hydrolysis-deficient Spastin mutant predicted to remain kinetically trapped on target proteins decorates microtubules in transfected cells. Analysis of disease-associated missense mutations shows that some more closely resemble the canonical hydrolysis mutant, whereas others resemble the ATP-binding mutant. Using real-time imaging, we show that Spastin severs microtubules when added to permeabilized, cytosol-depleted cells stably expressing GFP-tubulin. Using purified components, we also show that Spastin interacts directly with microtubules and is sufficient for severing. These studies suggest that defects in microtubule severing are a cause of axonal degeneration in human disease.
Spastin, an AAA ATPase mutated in the neurodegenerative disease hereditary spastic paraplegia, severs microtubules. Many other AAA proteins form ring-shaped hexamers and contain pore loops, which ...project into the ring's central cavity and act as ratchets that pull on target proteins, leading, in some cases, to conformational changes. We show that Spastin assembles into a hexamer and that loops within the central pore recognize C-terminal amino acids of tubulin. Key pore loop amino acids are required for severing, including one altered by a disease-associated mutation. We also show that Spastin contains a second microtubule binding domain that makes a distinct interaction with microtubules and is required for severing. Given that Spastin engages the MT in two places and that both interactions are required for severing, we propose that severing occurs by forces exerted on the C-terminal tail of tubulin, which results in a conformational change in tubulin, which releases it from the polymer.
Hereditary spastic paraplegia (HSP) is a neurodegenerative disorder that is characterized by retrograde axonal degeneration that primarily affects long spinal neurons. The disease is clinically ...heterogeneous, and there are >20 genetic loci identified. Here, we show a physical interaction between spastin and atlastin, two autosomal dominant HSP gene products. Spastin encodes a microtubule (MT)-severing AAA ATPase (ATPase associated with various activities), and atlastin encodes a Golgi-localized integral membrane protein GTPase. Atlastin does not regulate the enzymatic activity of spastin. We also identified a clinical mutation in atlastin outside of the GTPase domain that prevents interaction with spastin in cells. Therefore, we hypothesize that failure of appropriate interaction between these two HSP gene products may be pathogenetically relevant. These data indicate that at least a subset of HSP genes may define a cellular biological pathway that is important in axonal maintenance.
Nicotinic acid (niacin) induces beneficial changes in serum lipoproteins and has been associated with beneficial cardiovascular effects. Niacin reduces low-density lipoprotein, increases high-density ...lipoprotein, and decreases triglycerides. It is well established that activation of the seven-transmembrane G(i)-coupled receptor GPR109A on Langerhans cells results in release of prostaglandin D₂, which mediates the well-known flushing side effect of niacin. Niacin activation of GPR109A on adipocytes also mediates the transient reduction of plasma free fatty acid (FFA) levels characteristic of niacin, which has been long hypothesized to be the mechanism underlying the changes in the serum lipid profile. We tested this "FFA hypothesis" and the hypothesis that niacin lipid efficacy is mediated via GPR109A by dosing mice lacking GPR109A with niacin and testing two novel, full GPR109A agonists, MK-1903 and SCH900271, in three human clinical trials. In mice, the absence of GPR109A had no effect on niacin's lipid efficacy despite complete abrogation of the anti-lipolytic effect. Both MK-1903 and SCH900271 lowered FFAs acutely in humans; however, neither had the expected effects on serum lipids. Chronic FFA suppression was not sustainable via GPR109A agonism with niacin, MK-1903, or SCH900271. We conclude that the GPR109A receptor does not mediate niacin's lipid efficacy, challenging the long-standing FFA hypothesis.
AAA+ adenosine triphosphatases (ATPases) are molecular machines that perform a wide variety of cellular functions. For instance, they can act in vesicle transport, organelle assembly, membrane ...dynamics and protein unfolding. In most cases, the ATPase domains of these proteins assemble into active ring-shaped hexamers. As AAA+ proteins have a common structure, a central issue is determining how they use conserved mechanistic principles to accomplish specific biological actions. Here, we review the features and motifs that partially define AAA+ domains, describe the cellular activities mediated by selected AAA+ proteins and discuss the recent work, suggesting that various AAA+ machines with very different activities employ a common core mechanism. The importance of this mechanism to human health is demonstrated by the number of genetic diseases caused by mutant AAA+ proteins.
Aim
This phase III, multicentre, randomized study (ClinicalTrials.gov; NCT01958671) evaluated the efficacy and safety of ertugliflozin monotherapy in adults with inadequately controlled type 2 ...diabetes (glycated haemoglobin HbA1c, 7.0% to 10.5% 53‐91 mmol/mol) despite diet and exercise.
Materials and methods
The 52‐week study comprised a 26‐week, double‐blind, placebo‐controlled period (Phase A) during which 461 participants received placebo, ertugliflozin 5 mg/d or ertugliflozin 15 mg/d. This was followed by a 26‐week active‐controlled period (Phase B) during which participants in the placebo group who had not received glycaemic rescue therapy had blinded metformin added. Results to Week 52 are reported. Because of the use of metformin in Phase B, no statistical comparisons of efficacy were made between the ertugliflozin and placebo/metformin groups at Week 52.
Results
The mean (standard error) change from baseline to Week 52 in HbA1c was −0.9% (0.1) and −1.0% (0.1) in the ertugliflozin 5 and 15 mg groups, respectively. The proportions of participants with HbA1c <7.0% at Week 52 were 25.6% and 28.5%, respectively. Ertugliflozin reduced fasting plasma glucose, body weight and systolic blood pressure (SBP). The incidence of genital mycotic infections (GMIs) in females was significantly higher in both ertugliflozin groups (5 mg, 26.9%; 15 mg, 29.0%) vs the placebo/metformin group (9.9%), and in males was significantly higher in the 15 mg group (7.8%) vs the placebo/metformin group (1.2%). Ertugliflozin was not associated with increased incidence of urinary tract infections, symptomatic hypoglycaemia or hypovolaemia adverse events compared with placebo/metformin.
Conclusions
Ertugliflozin treatment over 52 weeks improved glycaemic control and reduced body weight and SBP, but increased GMIs.
Ertugliflozin is an inhibitor of sodium-glucose co-transporter-2 (SGLT2), approved in the United States and European Union to improve glycemic control in adults with type 2 diabetes mellitus (T2DM). ...The VERTIS cardiovascular (CV) outcomes trial (NCT01986881) has a primary objective to demonstrate non-inferiority of ertugliflozin versus placebo on major adverse CV events: time to the first event of CV death, nonfatal myocardial infarction, or nonfatal stroke. Secondary objectives are to demonstrate superiority of ertugliflozin versus placebo on time to: 1) the composite outcome of CV death or hospitalization for heart failure (HF); 2) CV death; and 3) the composite outcome of renal death, dialysis/transplant, or doubling of serum creatinine from baseline.
Patients ≥40 years old with T2DM (HbA1c 7.0–10.5%) and established atherosclerotic cardiovascular disease (ASCVD) of the coronary, cerebral, and/or peripheral arterial systems, were randomized 1:1:1 to once daily double-blind placebo, ertugliflozin 5 mg or 15 mg added to existing therapy.
8246 patients were randomized and 8238 received at least 1 dose of investigational product. Mean age was 64.4 years, 11.0% were ≥75 years old, and mean diabetes duration was 12.9 years with screening HbA1c of 8.3%. At entry, coronary artery disease, cerebrovascular disease, and peripheral arterial disease were present in 76.3%, 23.1%, and 18.8% of patients, respectively. HF was present in 23.1%, and Stage 3 kidney disease in 21.6% of patients.
The results from the VERTIS-CV trial will define the CV and renal safety and efficacy of ertugliflozin in patients with T2DM and ASCVD.
Aim
To evaluate the long‐term efficacy and safety of ertugliflozin in adults with type 2 diabetes mellitus inadequately controlled on metformin.
Materials and Methods
A 104‐week Phase III, randomized ...double‐blind study with a 26‐week placebo‐controlled period (Phase A) and a 78‐week period (Phase B) where blinded glimepiride was added to non‐rescued placebo participants with fasting fingerstick glucose ≥6.1 mmol/L. Results through week 104 are reported.
Results
Mean (standard error) change in HbA1c from baseline was −0.7% (0.07) and −1.0% (0.07) at week 52; −0.6% (0.08) and −0.9% (0.08) at week 104 for ertugliflozin 5 and 15 mg. At week 52, 34.8% and 36.6% participants had HbA1c <7.0%, and 24.6% and 33.7% at week 104, for ertugliflozin 5 and 15 mg. Ertugliflozin reduced fasting plasma glucose (FPG), body weight and systolic blood pressure (SBP) from baseline through week 104. The incidence of female genital mycotic infections (GMIs) was higher with ertugliflozin, and symptomatic hypoglycaemia was lower for ertugliflozin versus placebo/glimepiride. Minimal bone mineral density (BMD) changes were observed, similar to placebo/glimepiride, except at total hip where reduction in BMD was greater with ertugliflozin 15 mg versus placebo/glimepiride: difference in least squares means (95% CI) –0.50% (−0.95, −0.04) at week 52 and −0.84% (−1.44, −0.24) at week 104.
Conclusions
Ertugliflozin maintained improvements from baseline in HbA1c, FPG, body weight and SBP through week 104. Ertugliflozin was well tolerated, with non‐clinically relevant changes in BMD. Compared with placebo/glimepiride, ertugliflozin increased female GMIs, but reduced the incidence of symptomatic hypoglycaemia. ClinicalTrials.gov Identifier: NCT02033889.
Chaperones and folding cofactors are known to mediate posttranslational folding of nascent tubulin, thus forming functional dimers. Based on sequence likeness, a novel protein similar to cofactor E, ...E-like protein (El), was identified. In overexpression experiments El, similar to a subset of folding factors (i.e. cofactors D and E), appears to disrupt functional dimers and target them for destruction by the proteasome. El apparently does not interact with microtubules directly and has no function in the tubulin folding pathway. Suppression of El expression seems to increase the cellular content of stable, posttranslationally modified microtubules by an unknown mechanism. Degradation of functional tubulin dimers as well as the alteration of the cellular content of stable microtubules through El might regulate the distribution and organization of organelles
in vivo.
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