Characterization of triacylglyceride lipase and mono- and diacylglycerol acyltransferases in Manduca sexta

Triglyceride (TG) is the main form of lipid storage in the cell. The processes of hydrolysis and synthesis of TG play critical roles the lipid metabolism. Triglyceridelipase(TGL) is a major fat body lipase hydrolyzing TG in Manduca sexta. A WWE domain, presumably involved in protein-protein interactions, has been previously identified in the N-terminal region of TGL. So we searched for proteins partners that interact with the N-terminal region of TGL. Thirteen proteins were identified by mass spectrometry. The oxidoreductase lipoamide-dehydrogenase (LipDH) and the apolipoprotein components of the lipid transporter, HDLp, were among these proteins. LipDH is the common component of the mitochondrial ?-keto acid dehydrogenase complexes whereas HDLp occurs in the hemolymph. However, subcellular fractionation demonstrated these two proteins are relatively abundant in the soluble fraction of fat body adipocytes. TGL has critical thiol groups and studies with inhibitors suggested that LipDH, acting as a diaphorase could preserve the activity of TGL by controlling the redox state of thiol groups. The HDLp-TGL interaction affected the catalytic properties of TGL leading to a lower rate of hydrolysis of diacylglycerol (DG).Monoacylglycerol acyltransferase (MGAT) and diacylglycerol acyltransferase (DGAT) are key enzymes of the synthesis of neutral glycerides. Very little is known about these acyltransferases in insects. We have cloned two predicted MGATs and a DGAT from M. sexta and compared their sequences with predicted MGAT and DGAT homologues from a number of insect species. The comparison suggested that insects may only have a single DGAT gene, DGAT1 and insects seem to have a single MGAT gene which is similar to the MGAT2 of vertebrates. Furthermore, the expression patterns of the acyltransferases suggest a significant role of the monoacylglycerol pathway in the production and mobilization of DG in M. sexta fat body

SEIPIN Regulates Lipid Droplet Expansion and Adipocyte Development by Modulating the Activity of Glycerol-3-phosphate Acyltransferase

Berardinelli-Seip congenital lipodystrophy 2 (BSCL2) is caused by loss-of-function mutations in SEIPIN, a protein implicated in both adipogenesis and lipid droplet expansion but whose molecular function remains obscure. Here, we identify physical and functional interactions between SEIPIN and microsomal isoforms of glycerol-3-phosphate acyltransferase (GPAT) in multiple organisms. Compared to controls, GPAT activity was elevated in SEIPIN-deficient cells and tissues and GPAT kinetic values were altered. Increased GPAT activity appears to underpin the block in adipogenesis and abnormal lipid droplet morphology associated with SEIPIN loss. Overexpression of Gpat3 blocked adipogenesis, and Gpat3 knockdown in SEIPIN-deficient preadipocytes partially restored differentiation. GPAT overexpression in yeast, preadipocytes, and fly salivary glands also formed supersized lipid droplets. Finally, pharmacological inhibition of GPAT in Seipin-/- mouse preadipocytes partially restored adipogenesis. These data identify SEIPIN as an evolutionarily conserved regulator of microsomal GPAT and suggest that GPAT inhibitors might be useful for the treatment of human BSCL2 patients

Randomized Efficacy Trial of Conventional, TCM Herb, and TEAS on Bone Marrow Suppression in Patients with Small Cell Lung Cancer after Initial Chemotherapy

Objective. To compare the efficiency of transcutaneous electrical acupoint stimulation (TEAS) with those of conventional and TCM herb on bone marrow suppression in small cell lung cancer (SCLC) patients after initial chemotherapy. Methods. We recruited 139 participants with pathologically confirmed SCLC who had not received chemotherapy. The conventional group (n = 37) received gemcitabine and cisplatin chemotherapy and routine care. The TCM herb group (n = 35) received 3 Diyushengbai tablets thrice a day for one day prior to chemotherapy and maintained during the trial. The TEAS group (n = 42) received TEAS at a frequency of 65–100 Hz with a pulse width of 100–200 μsec. Acupoints were selected from Dazhui (DU14), Geshu (BL17), Zusanli (ST36), Sanyinjiao (SP6), and Hegu (LI4) and were treated on days 1, 2, 3, 5, 8, 14, 21, and 28 of chemotherapy for 30 min each day. All three groups underwent a 28-day treatment for a total of one treatment course. Changes in the white blood cell, neutrophil, platelet, and hemoglobin indices on day 1 before chemotherapy and days 5, 8, 11, 14, 21, and 28 days after chemotherapy were compared among the groups. Comfort levels of patients on day 1 before chemotherapy and days 5, 11, and 21 after chemotherapy were observed. Results. Compared with the conventional group, the white blood cell counts in the TEAS group on days 8 (7.07 ± 2.11 vs. 5.97 ± 2.10 × 109/L) and 14 (6.14 ± 1.51 vs. 5.07 ± 2.41 × 109/L) of chemotherapy and that in the TCM herb group on day 14 (6.63 ± 3.44 vs. 5.07 ± 2.41 × 109/L) of chemotherapy were increased (P<0.05). Compared with the conventional group, the neutrophil count in the TEAS group on days 5 (4.28 ± 1.54 vs. 3.01 ± 1.41 × 109/L), 8 (3.75 ± 1.21 vs. 2.77 ± 1.17 × 109/L), 11 (3.46 ± 1.31 vs. 2.31 ± 1.24 × 109/L), 14 (3.18 ± 1.29 vs. 2.07 ± 1.14 × 109/L), and 21 (4.67 ± 1.31 vs. 3.58 ± 1.23 × 109/L) of chemotherapy and that in the TCM herb group on day 5 (3.88 ± 1.05 vs. 3.01 ± 1.41 × 109/L) of chemotherapy were increased (P<0.05). Compared with the conventional group, the platelet count of patients in the TEAS group increased on days 5 (264.7 ± 64.1 vs. 201.0 ± 55.7 × 109/L), 8 (251.3 ± 74.9 vs. 188.2 ± 65.8 × 109/L), 11 (236.7 ± 74.9 vs. 181.3 ± 84.3 × 109/L), and 14 (238.3 ± 75.9 vs. 192.8 ± 95.8 × 109/L) of chemotherapy (P<0.05). Compared with the TCM herb group, the platelet count in the TEAS group increased on days 5 (264.7 ± 64.1 vs. 216.3 ± 57.9 × 109/L), 8 (251.3 ± 74.9 vs. 213.7 ± 70.3 × 109/L), 11 (236.7 ± 74.9 vs. 181.3 ± 84.3 × 109/L), and 21 (254.8 ± 81.8 vs. 213.9 ± 82.6 × 109/L) of chemotherapy (P<0.05). Compared with the conventional group, the hemoglobin level in the TCM herb group increased on day 14 (135.03 ± 28.06 vs. 122.09 ± 12.63 g/L) of chemotherapy (P<0.05). Compared with the conventional group, the comfort score of the TEAS group increased on days 5 (78.31 ± 10.21 vs. 70.18 ± 9.34 score) and 11 (80.07 ± 10.44 vs. 72.11 ± 9.47 score) of chemotherapy (P<0.05). Conclusion. TEAS is an effective and safe treatment modality for improving bone marrow suppression in SCLC patients after initial chemotherapy. TEAS improved comfort levels more effectively than did conventional and TCM herb

Precise Engineering of the Electrocatalytic Activity of FeN₄‑Embedded Graphene on Oxygen Electrode Reactions by Attaching Electrides

Using first-principles calculations combined with a constant-potential implicit solvent model, we comprehensively studied the activity of oxygen electrode reactions catalyzed by electride-supported FeN4-embedded graphene (FeN4Cx). The physical quantities in FeN4Cx/electrides, i.e., work function of electrides, interlayer spacing, stability of heterostructures, charge transferred to Fe, d-band center of Fe, and adsorption free energy of O, are highly intercorrelated, resulting in activity being fully expressed by the nature of the electrides themselves, thereby achieving a precise modulation in activity by selecting different electrides. Strikingly, the FeN4PDCx/Ca2N and FeN4PDCx/Y2C systems maintain a high oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) activity with the overpotential less than 0.46 and 0.62 V in a wide pH range. This work provides an effective strategy for the rational design of efficient bifunctional catalysts as well as a model system with a simple activity-descriptor, helping to realize significant advances in energy devices

SEIPIN regulates lipid droplet expansion and adipocyte development by modulating the activity of glycerol-3-phosphate acyltransferase

Summary Berardinelli-Seip congenital lipodystrophy 2 (BSCL2) is caused by loss-of-function mutations in SEIPIN, a protein implicated in both adipogenesis and lipid droplet expansion but whose molecular function remains obscure. Here, we identify physical and functional interactions between SEIPIN and microsomal isoforms of glycerol-3-phosphate acyltransferase (GPAT) in multiple organisms. Compared to controls, GPAT activity was elevated in SEIPIN-deficient cells and tissues and GPAT kinetic values were altered. Increased GPAT activity appears to underpin the block in adipogenesis and abnormal lipid droplet morphology associated with SEIPIN loss. Overexpression of Gpat3 blocked adipogenesis, and Gpat3 knockdown in SEIPIN-deficient preadipocytes partially restored differentiation. GPAT overexpression in yeast, preadipocytes, and fly salivary glands also formed supersized lipid droplets. Finally, pharmacological inhibition of GPAT in Seipin−/− mouse preadipocytes partially restored adipogenesis. These data identify SEIPIN as an evolutionarily conserved regulator of microsomal GPAT and suggest that GPAT inhibitors might be useful for the treatment of human BSCL2 patients

SEIPIN Regulates Lipid Droplet Expansion and Adipocyte Development by Modulating the Activity of Glycerol-3-phosphate Acyltransferase

Berardinelli-Seip congenital lipodystrophy 2 (BSCL2) is caused by loss-of-function mutations in SEIPIN, a protein implicated in both adipogenesis and lipid droplet expansion but whose molecular function remains obscure. Here, we identify physical and functional interactions between SEIPIN and microsomal isoforms of glycerol-3-phosphate acyltransferase (GPAT) in multiple organisms. Compared to controls, GPAT activity was elevated in SEIPIN-deficient cells and tissues and GPAT kinetic values were altered. Increased GPAT activity appears to underpin the block in adipogenesis and abnormal lipid droplet morphology associated with SEIPIN loss. Overexpression of Gpat3 blocked adipogenesis, and Gpat3 knockdown in SEIPIN-deficient preadipocytes partially restored differentiation. GPAT overexpression in yeast, preadipocytes, and fly salivary glands also formed supersized lipid droplets. Finally, pharmacological inhibition of GPAT in Seipin−/− mouse preadipocytes partially restored adipogenesis. These data identify SEIPIN as an evolutionarily conserved regulator of microsomal GPAT and suggest that GPAT inhibitors might be useful for the treatment of human BSCL2 patients