Hepatoma-derived growth factor. Significance of amino acid residues 81-100 in cell surface interaction and proliferative activity

Hepatoma-derived growth factor (HDGF) has proliferative, angiogenic, and neurotrophic activity. It plays a putative role in the development and progression of cancer. When expressed in cells, the mitogenic activity of HDGF depends on its nuclear localization, but it also stimulates proliferation when added to the cell culture medium. A cell surface receptor for HDGF has not been identified so far. We investigated the interaction of various purified recombinant HDGF fusion proteins with the cell surface of NIH 3T3 fibroblasts. We showed that binding of a HDGF-beta-galactosidase fusion protein to the cell surface of NIH 3T3 fibroblasts was saturable, occurred with high affinity (K(D) = 14 nm), and had a proliferative effect. We identified a peptide comprising amino acid residues 81-100 within the amino-terminal part of HDGF that bound to the cell surface of NIH 3T3 cells with saturation and affinity values similar to those of HDGF. When added to primary human fibroblasts, this peptide stimulated proliferation. Substitution of a single amino acid (K96A) within this peptide was sufficient to abolish its binding to the cell surface and its proliferative activity. In contrast, when expressed transiently in NIH 3T3 cells, a HDGF-beta-galactosidase fusion protein in which amino acid residues 81-100 were deleted still had proliferative activity, whereas a fusion protein containing only the 81-100 peptide did not. Our results suggest the existence of a plasma membrane-located HDGF receptor for which signaling depends on amino acid residues 81-100 of HDGF. This region differs from the one that has been recently identified to be essential for mitogenic activity depending on the nuclear localization of HDGF. Thus, HDGF exerts its proliferative activity via two different pathways.     

Diabetic Foot Complications and Their Risk Factors from a Large Retrospective Cohort Study

BackgroundFoot complications are considered to be a serious consequence of diabetes mellitus, posing a major medical and economical threat. Identifying the extent of this problem and its risk factors will enable health providers to set up better prevention programs. Saudi National Diabetes Registry (SNDR), being a large database source, would be the best tool to evaluate this problem.MethodsThis is a cross-sectional study of a cohort of 62,681 patients aged ≥25 years from SNDR database, selected for studying foot complications associated with diabetes and related risk factors.ResultsThe overall prevalence of diabetic foot complications was 3.3% with 95% confidence interval (95% CI) of (3.16%–3.44%), whilst the prevalences of foot ulcer, gangrene, and amputations were 2.05% (1.94%–2.16%), 0.19% (0.16%–0.22%), and 1.06% (0.98%–1.14%), respectively. The prevalence of foot complications increased with age and diabetes duration predominantly amongst the male patients. Diabetic foot is more commonly seen among type 2 patients, although it is more prevalent among type 1 diabetic patients. The Univariate analysis showed Charcot joints, peripheral vascular disease (PVD), neuropathy, diabetes duration ≥10 years, insulin use, retinopathy, nephropathy, age ≥45 years, cerebral vascular disease (CVD), poor glycemic control, coronary artery disease (CAD), male gender, smoking, and hypertension to be significant risk factors with odds ratio and 95% CI at 42.53 (18.16–99.62), 14.47 (8.99–23.31), 12.06 (10.54–13.80), 7.22 (6.10–8.55), 4.69 (4.28–5.14), 4.45 (4.05–4.89), 2.88 (2.43–3.40), 2.81 (2.31–3.43), 2.24 (1.98–2.45), 2.02 (1.84–2.22), 1.54 (1.29–1.83), and 1.51 (1.38–1.65), respectively.ConclusionsRisk factors for diabetic foot complications are highly prevalent; they have put these complications at a higher rate and warrant primary and secondary prevention programs to minimize morbidity and mortality in addition to economic impact of the complications. Other measurements, such as decompression of lower extremity nerves, should be considered among diabetic patients.     

Synthesis,anti-inflammatory,cytotoxic, and COX-1/2 inhibitory activities of cyclic imides bearing 3-benzenesulfonamide,oxime, and β-phenylalanine scaffolds: a molecular docking study

Abstract

Cyclic imides containing 3-benzenesulfonamide, oxime, and β-phenylalanine derivatives were synthesised and evaluated to elucidate their in vivo anti-inflammatory and ulcerogenic activity and in vitro cytotoxic effects. Most active anti-inflammatory agents were subjected to in vitro COX-1/2 inhibition assay. 3-Benzenesulfonamides (2–4, and 9), oximes (11–13), and β-phenylalanine derivative (18) showed potential anti-inflammatory activities with 71.2–82.9% oedema inhibition relative to celecoxib and diclofenac (85.6 and 83.4%, respectively). Most active cyclic imides 4, 9, 12, 13, and 18 possessed ED₅₀ of 35.4–45.3?mg kg^?1 relative to that of celecoxib (34.1?mg kg^?1). For the cytotoxic evaluation, the selected derivatives 2–6 and 8 exhibited weak positive cytotoxic effects (PCE = 2/59–5/59) at 10?μM compared to the standard drug, imatinib (PCE = 20/59). Cyclic imides bearing 3-benzenesulfonamide (2–5, and 9), acetophenone oxime (11–14, 18, and 19) exhibited high selectivity against COX-2 with SI > 55.6–333.3 relative to that for celecoxib [SI > 387.6]. β-Phenylalanine derivatives 21–24 and 28 were non-selective towards COX-1/2 isozymes as indicated by their SI of 0.46–0.68.     

Exploring structure-activity relationship of S-substituted 2-mercaptoquinazolin-4(3H)-one including 4-ethylbenzenesulfonamides as human carbonic anhydrase inhibitors

Abstract

Inhibitory action of newly synthesised 4-(2-(2-substituted-thio-4-oxoquinazolin-3(4H)-yl)ethyl)benzenesulfonamides compounds 2–13 against human carbonic anhydrase (CA, EC 4.2.1.1) (hCA) isoforms I, II, IX, and XII, was evaluated. hCA I was efficiently inhibited by compounds 2–13 with inhibition constants (K_Is) ranging from 57.8–740.2?nM. Compounds 2, 3, 4, and 12 showed inhibitory action against hCA II with K_Is between 6.4 and 14.2?nM. CA IX exhibited significant sensitivity to inhibition by derivatives 2–13 with K_I values ranging from 7.1 to 93.6?nM. Compounds 2, 3, 4, 8, 9, and 12 also exerted potent inhibitory action against hCA XII (K_Is ranging from 3.1 to 20.2?nM). Molecular docking studies for the most potent compounds 2 and 3 were conducted to exhibit the binding mode towards hCA isoforms as a promising step for SAR analyses which showed similar interaction with co-crystallized ligands. As such, a subset of these mercaptoquinazolin-4(3H)-one compounds represented interesting leads for developing new efficient and selective carbonic anhydrase inhibitors (CAIs) for the management of a variety of diseases including glaucoma, epilepsy, arthritis and cancer.     

A novel three-TMH Na+/H+ antiporter and the functional role of its oligomerization

Na⁺/H⁺ antiporters are a category of ubiquitous transmembrane proteins with various important physiological roles in almost all living organisms ranging from bacteria to humans. However, the knowledge of novel Na⁺/H⁺ antiporters remains to be broadened, and the functional roles of oligomerization in these antiporters have not yet been thoroughly understood. Here, we reported functional analysis of an unknown transmembrane protein composed of 103 amino acid residues. This protein was found to function as a Na⁺(Li⁺, K⁺)/H⁺ antiporter. To the best of our knowledge, this antiporter is the minimal one of known Na⁺/H⁺ antiporters and thus designated as NhaM to represent the minimal Na⁺/H⁺ antiporter. NhaM and its homologs have not yet been classified into any protein family. Based on phylogenetic analysis and protein alignment, we propose NhaM and its homologs to constitute a novel transporter family designated as NhaM family. More importantly, we found that NhaM is assembled with parallel protomers into a homo-oligomer and oligomerization is vital for the function of this antiporter. This implies that NhaM may adopt and require an oligomer structure for its normal function to create a similar X-shaped structure to that of the NhaA fold. Taken together, current findings not only present the proposal of a novel transporter family but also positively contribute to the functional roles of oligomerization in Na⁺/H⁺ antiporters.     

Influence of doxycycline administration on rat embryonic development during organogenesis

This experiment was performed to evaluate the possible embryotoxic and teratogenic effects of doxycycline during rat development. Twenty‐one female rats were used and distributed into three groups equally (seven animals/group). The low dose group received doxycycline at a dose of 5 mg/kg bw/day orally from the 6th to 14th day of gestation. The high dose group received 10 mg/kg bw/day orally for the same period, the Control group received 1 mL distilled water orally for the same period. The dams were dissected on the 20th day of gestation and their fetuses were subjected to morphological, skeletal, and histological examination. Moreover, DNA damage analysis of liver cells of pregnant rats and their fetuses or fetal skull was assessed by Comet assay. The obtained results showed a significant decrease in fetal body weight, several morphological anomalies, and severe lack of ossification on the skull bones, phalanges, and sternum bone as well as shortness in the ulna and radius bones. Histological studies of pregnant rats revealed congestion and dilatation of the central vein of the liver lobules and fatty degeneration of the hepatocytes. In addition, 20 day‐fetuses showed a marked increase of necrotic hepatocytes associated with an increased average of megakaryocytes and periportal leukocytic infiltration. Moreover, doxycycline induced a significant increase in the percentage of DNA damage and tail length of examined samples. Conclusively, doxycycline caused certain fetal abnormalities, so it is advisable to avoid using this drug during pregnancy.     

Triphala extract negates arecoline-induced senescence in oral mucosal epithelial cells in vitro

BackgroundArecoline found in areca nut causes oral submucous fibrosis. Triphala is an Ayurvedic medicinal preparation used to improve overall physical wellness that has also been shown to improve oral health.ObjectivesTo assess the activity of Triphala extract on arecoline-induced senescence in oral mucosal epithelial cells in vitro.Materials and methodsOral mucosal epithelial cells were isolated and cultured in vitro. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to assess the viability of treated cells, while senescence was assessed by senescence-associated-β-galactosidase staining. Cell surface marker expression was analyzed by flow cytometry. Finally, real-time quantitative polymerase chain reaction was performed to examine gene expression levels.ResultsTriphala extract (5 µg/mL) reversed the cell senescence activity of arecoline, as evidenced by reduced β-galactosidase activity, increased Ki-67 marker expression, and reduced expression of senescence-related genes p16 and p21.ConclusionTriphala extract helped to reduce the pathological effects of arecoline-induced pathogenesis.Clinical relevance.Arecoline found in the areca nut causes oral pathological conditions including oral submucous fibrosis. Our results showed that Triphala counteracted the adverse effects of arecoline, in particular, negating senescence in oral mucosal epithelial cells. As a translational effect, Triphala treatment could restore normal epithelial thickness in oral submucous fibrosis, thus reducing the clinical severity of the disease. This reestablishment of oral homeostasis would help to improve oral health-related quality of life in patients with oral submucous fibrosis.