Intrinsic signaling pathways modulate targeted protein degradation.

Targeted protein degradation is a groundbreaking modality in drug discovery; however, the regulatory mechanisms are still not fully understood. Here, we identify cellular signaling pathways that modulate the targeted degradation of the anticancer target BRD4 and related neosubstrates BRD2/3 and CDK9 induced by CRL2VHL- or CRL4CRBN -based PROTACs. The chemicals identified as degradation enhancers include inhibitors of cellular signaling pathways such as poly-ADP ribosylation (PARG inhibitor PDD00017273), unfolded protein response (PERK inhibitor GSK2606414), and protein stabilization (HSP90 inhibitor luminespib). Mechanistically, PARG inhibition promotes TRIP12-mediated K29/K48-linked branched ubiquitylation of BRD4 by facilitating chromatin dissociation of BRD4 and formation of the BRD4-PROTAC-CRL2VHL ternary complex; by contrast, HSP90 inhibition promotes BRD4 degradation after the ubiquitylation step. Consequently, these signal inhibitors sensitize cells to the PROTAC-induced apoptosis. These results suggest that various cell-intrinsic signaling pathways spontaneously counteract chemically induced target degradation at multiple steps, which could be liberated by specific inhibitors.

Senescent cells form nuclear foci that contain the 26S proteasome.

The proteasome plays a central role in intracellular protein degradation. Age-dependent decline in proteasome activity is associated with cellular senescence and organismal aging; however, the mechanism by which the proteasome plays a role in senescent cells remains elusive. Here, we show that nuclear foci that contain the proteasome and exhibit liquid-like properties are formed in senescent cells. The formation of senescence-associated nuclear proteasome foci (SANPs) is dependent on ubiquitination and RAD23B, similar to previously known nuclear proteasome foci, but also requires proteasome activity. RAD23B knockdown suppresses SANP formation and increases mitochondrial activity, leading to reactive oxygen species production without affecting other senescence traits such as cell-cycle arrest and cell morphology. These findings suggest that SANPs are an important feature of senescent cells and uncover a mechanism by which the proteasome plays a role in senescent cells.

Relationship between the efficacy of oral antidiabetic drugs and clinical features in type 2 diabetic patients (JDDM38).

AIMS/INTRODUCTION: We carried out an observational cohort study to examine the relationship between the efficacy of oral antidiabetic drugs and clinical features in type 2 diabetics. MATERIALS AND METHODS: We analyzed the CoDiC(®) database of the Japan Diabetes Data Management Study Group across 67 institutions in Japan. In a total of 3,698 drug-naïve patients who were initiated with metformin, dipeptidyl peptidase-4 inhibitor (DPP-4i) or sulfonylurea (SU) from 2007 to 2012, we evaluated body mass index (BMI) and hemoglobin A1c (HbA1c). The patients were stratified according to their clinical features, and matched using a propensity score to adjust for baseline factors. RESULTS: HbA1c was reduced with all drugs, with the largest effect elicited by DPP-4i and the smallest by SU (P = 0.00). HbA1c increased with SU after 6 months in the patients stratified by an age-of-onset of <50 years (P = 0.00). BMI increased with SU in the patients stratified by a BMI of <25 (P = 0.00), and decreased with metformin in the patients with a BMI >25 (P = 0.00). The reduction in HbA1c was larger in patients with HbA1c of ≥8%, compared with that in patients with HbA1c of <8% (P = 0.00). HbA1c during the study period was higher in patients who were added to or swapped with other drug(s), than in patients continued on the original drug (P = 0.00). CONCLUSIONS: The effect on bodyweight and glycemic control differed among metformin, DPP-4i and SU, and the difference was associated with clinical features.

Wettability evaluation of hydrophilic-hydrophobic nanohybrid silica thin films using picoliter water droplets.

Water wettabilities of hydrophilic-hydrophobic nanohybrid silica thin films were investigated by contact angles of extremely small size water droplets (8 pL-1 nL) and using an antifog analyzer. The nanohybrid silica was prepared via our unique sol-gel process based on tetramethoxysilane (TMOS) and metyltrimethoxysilane (MTMS) with a hydroxyacetone catalyst, in which hydrophilic portion was generated from hydrolysis of microporous silica prepared from TMOS and hydrophobic portion was directly prepared from MTMS. The sizes of these domains were controlled by the growth time of the microporous precursor polymers in solution. The hydrophilic and hydrophobic domains in the nanohybrid surface were visualized and confirmed by a lateral-mode friction force microscopy using the cantilever modified with self-assembled monolayers of mercaptohexadecanol. Using a small size of water droplets (< 100 pL), the contact angles for the nanohybrid silica films were lower than those for the wholly hydrophilic silica. The small size of the water droplet has a characteristic effect on the lower contact angle on the nanohybrid silica. The contact angles using the small size 70 pL of the water droplet on the nanohybrid silica films at [MTMS]/[TMOS] ratios from 0.25 to 0.75 were lower than those using the conventional size 2 microL. The dependence of the [MTMS]/[TMOS] ratio in the preparation on the antifog parameter was similar to that on the contact angle using the small size 70 pL of the water droplet. The use of the small water droplet for the contact angle measurement was suitable for the evaluation of the antifog films.

Attainment of the Japanese Society for Dialysis Therapy guidelines for the management of secondary hyperparathyroidism in chronic hemodialysis patients in our clinic.

The treatment according to the Japanese Society for Dialysis Therapy guidelines was performed in 189 patients on maintenance dialysis in our clinic. The mean age of the patients was 64.9 years and the mean dialysis period was 6.3 years. The underlying disease was diabetic nephropathy in 40.7% of the patients, chronic glomerulonephritis in 30.2%, and nephrosclerosis in 13.8%. In May 2006 before the use of JSDT guidelines, patients with phosphorus and calcium concentrations in the control goal range were most frequently observed (69.8%), followed in order by those with a high concentration of phosphorus alone (13.8%), those with a low concentration of phosphorus alone (2.6%), those with a high concentration of calcium alone (10.1%), those with high concentration of both phosphorus and calcium (3.7%). Treatment according to JSDT guidelines was performed for 6 months in these patients. In January 2007, the group with both phosphorus and calcium concentrations in the goal range accounted for 82.2%, showing improvement. The intact PTH concentration in patients with normal phosphorus and calcium concentration was in the reference range (60-180 pg/ml) in about 50% of the patients, high (>180 pg/ml) in 35%, low (<60 pg/ml) in 10% during the study periods. The intact PTH concentration was often about 40 pg/ml in patients with a concentration <60 pg/ml, 120 pg/ml in those with a concentration of 60-180 pg/ml, and 200-250 pg/ml in those with a concentration >180 pg/ml. The concentration of NTx was significantly higher in the patients with an intact PTH concentration >180 pg/ml than in those with a concentration of <60 pg/ml or those with a concentration of 60-180 pg/ml and significantly increased with time.