Honokiol: A non-adipogenic PPARγ agonist from nature

Background

Peroxisome proliferator-activated receptor gamma (PPARγ) agonists are clinically used to counteract hyperglycemia. However, so far experienced unwanted side effects, such as weight gain, promote the search for new PPARγ activators.

Methods

We used a combination of in silico, in vitro, cell-based and in vivo models to identify and validate natural products as promising leads for partial novel PPARγ agonists.

Results

The natural product honokiol from the traditional Chinese herbal drug Magnolia bark was in silico predicted to bind into the PPARγ ligand binding pocket as dimer. Honokiol indeed directly bound to purified PPARγ ligand-binding domain (LBD) and acted as partial agonist in a PPARγ-mediated luciferase reporter assay. Honokiol was then directly compared to the clinically used full agonist pioglitazone with regard to stimulation of glucose uptake in adipocytes as well as adipogenic differentiation in 3T3-L1 pre-adipocytes and mouse embryonic fibroblasts. While honokiol stimulated basal glucose uptake to a similar extent as pioglitazone, it did not induce adipogenesis in contrast to pioglitazone. In diabetic KKAy mice oral application of honokiol prevented hyperglycemia and suppressed weight gain.

Conclusion

We identified honokiol as a partial non-adipogenic PPARγ agonist in vitro which prevented hyperglycemia and weight gain in vivo.

General significance

This observed activity profile suggests honokiol as promising new pharmaceutical lead or dietary supplement to combat metabolic disease, and provides a molecular explanation for the use of Magnolia in traditional medicine.     

Combined effect of gamma radiation,hot water and sodium bicarbonate on quality and chemical constituents of stored mandarin fruits

The combined effect of gamma radiation and both hot water and sodium carbonate on physiological decay and chemical constituents of stored mandarin fruits was investigated in this work. In this consideration, the studied fruits were gamma irradiated at doses of 0, 0.3, 0.6, 1.2 and 2.4 KGy. Then, the irradiated and non-irradiated fruits were treated either by hot water or sodium bicarbonate to examine their capacity to give a further maintenance and increasing shelf life or storage periods of mandarin. Treated and non-treated fruit samples were taken at intervals of 10 days and up to 60 days. Physiological decay, total acidity, vitamin C, total sugars and TSS were investigated during the different intervals. Gamma radiation treatments showed a promising effect for maintaining the studied fruits and retarding the development of decay. On the other hand, applying both hot water and sodium bicarbonate as a further combined treatments induced a powerful effect on delaying decay development, keeping the chemical constituents near to the normal level and in turn maximizing shelf life and storage periods of the fruits under investigation.     

Expression patterns of peroxisome proliferator-activated receptor gamma 1 versus gamma 2, and their association with intramuscular fat in goat tissues

Intramuscular fat (IMF) shortage causes the lack of juiciness and tenderness of goat meat, while peroxisome proliferator-activated receptor gamma 1 (PPARγ1) and gamma 2 (PPARγ2) play key roles in lipid metabolism. Nevertheless, their expression patterns and the relationship with IMF have been poorly exposed. Using quantitative polymerase chain reaction (qPCR), classical Soxhlet extraction, and in situ hybridization, we demonstrated that among 13 goat tissues, expression of PPARγ1 was dramatically higher than that of PPARγ2 except for lung. We further demonstrated the expression patterns of PPARγ1 and PPARγ2 and their negative association with intramuscular fat content in three goat muscles with kids growing. Meanwhile, PPARγ expression was located in the connective tissues. These results suggest that PPARγ1 is rather active for most tissues of goat, and closely related with the muscular fat metabolism during early postnatal life, but a more direct proof remains to be provided.     

Association of peroxisome proliferator activated receptor-γ gene with non-alcoholic fatty liver disease in Asian Indians residing in north India

Background

Genetics of non-alcoholic fatty liver (NAFLD) in Asian Indians has been inadequately studied. We investigated the association of polymorphisms C161T and Pro12Ala of peroxisome proliferator-activated receptor gamma (PPARγ) with clinical and biochemical parameters in Asian Indians with NAFLD.

Methods

In this case–control study, 162 NAFLD cases and 173 controls were recruited. Abdominal ultrasound, clinical and biochemical profiles, fasting insulin levels and value of homeostasis model assessment of insulin resistance were determined. Polymerase chain reaction–restriction fragment length polymorphisms of two polymorphisms were performed. The association of these polymorphisms with clinical and biochemical parameters was analysed.

Results

Higher frequency of Ala and T alleles of PPARγ was obtained in cases. Ala/Ala genotype of PPARγ (Pro12Ala) was associated with significantly higher serum triglycerides (TG), alkaline phosphatase (ALK) and waist–hip ratio in cases as compared to controls. In C161T polymorphism, TT genotype was significantly increased TG (p = 0.04), total cholesterol (p = 0.01), ALK (p = 0.04) and gamma-glutamyl transpeptidase (p = 0.007) in cases. The linkage disequilibrium for these two single-nucleotide polymorphisms of PPARγ was differed in cases (D1 = 0.1; p = 0.006) and controls (D1 = 0.07; p = 0.1). Using a multivariate analysis after adjusting for age, sex and body mass index, the presence of NAFLD was linked to these two polymorphisms (odds ratio 1.64 (95% CI: 1.09–2.45, p = 0.05)].

Conclusion

Asian Indians in north India carrying the alleles Ala and T of PPARγ (Pro12Ala and C161T) polymorphisms are predisposed to develop NAFLD.     

Contribution of genetic and epigenetic mechanisms to Wnt pathway activity in prevalent skeletal disorders

We reported previously that the expression of Wnt-related genes is lower in osteoporotic hip fractures than in osteoarthritis. We aimed to confirm those results by analyzing β-catenin levels and explored potential genetic and epigenetic mechanisms involved.     

Hemocyanin gene family evolution in spiders (Araneae), with implications for phylogenetic relationships and divergence times in the infraorder Mygalomorphae

Hemocyanins are multimeric copper-containing hemolymph proteins involved in oxygen binding and transport in all major arthropod lineages. Most arachnids have seven primary subunits (encoded by paralogous genes a–g), which combine to form a 24-mer (4 × 6) quaternary structure. Within some spider lineages, however, hemocyanin evolution has been a dynamic process with extensive paralog duplication and loss. We have obtained hemocyanin gene sequences from numerous representatives of the spider infraorders Mygalomorphae and Araneomorphae in order to infer the evolution of the hemocyanin gene family and estimate spider relationships using these conserved loci. Our hemocyanin gene tree is largely consistent with the previous hypotheses of paralog relationships based on immunological studies, but reveals some discrepancies in which paralog types have been lost or duplicated in specific spider lineages. Analyses of concatenated hemocyanin sequences resolved deep nodes in the spider phylogeny and recovered a number of clades that are supported by other molecular studies, particularly for mygalomorph taxa. The concatenated data set is also used to estimate dates of higher-level spider divergences and suggests that the diversification of extant mygalomorphs preceded that of extant araneomorphs. Spiders are diverse in behavior and respiratory morphology, and our results are beneficial for comparative analyses of spider respiration. Lastly, the conserved hemocyanin sequences allow for the inference of spider relationships and ancient divergence dates.     

Effects of combined centrifugation and ultraviolet irradiation of eggs on pattern formation in Chironomus embryos

Summary

Combined mild centrifugation and uv irradiation of Chironomus embryos modified the developmental types expected from centrifugation alone, somewhat differently from the combined strong centrifugation and uv irradiation of Smittia embryos. The modifications changed with the stages irradiated. The change caused by anterior irradiation may depend on whether or not a part of the cytoplasmic zone is irradiated simultaneously with the anterior yolky end; because most of the cytoplasm lies in the posterior half of egg at early irradiation, while the tip of the cytoplasm redistributes near the anterior end by the late irradiation. Early uv irradiation of the anterior end of centrifuged eggs, causing the formation of a double abdomen (DA) or an inverted embryo, is not photoreversible, while the uv damage to the anterior end of uncentrifuged eggs, inducing DA, is. These facts suggest that there is another photoirreversible uv target in addition to the photoreversible target for DA induction or the anterior determinant shown in Smittia. Other changes, such as the induction of a double cephalon by late irradiation of the centrifuged egg, are photoreversible, but in an unusual way in that the level of photorecovery is similar to the result of incubation in the dark after early irradiation, and not to that of the centrifuged controls. These modified results were then compared with those for Smittia embryos.     

Lethal and sub‐lethal impacts of pulsed laser irradiations on the larvae of the fouling barnacle Balanus amphitrite

Laboratory experiments were conducted to study the impact of laser irradiation on the larvae of the fouling barnacle Balanus amphitrite. Research pertaining to fouling invertebrate larvae‐laser interaction is sparse and, hence, data on this aspect were thought significant in order to consider pulsed low power laser irradiations as a possible future antifouling tool. Lethal and sub‐lethal impacts of four very low laser fluences, viz. 0.013, 0.025, 0.05 and 0.1 J cm^‐2 for three different durations, viz. 2, 10 and 30 s were investigated. Three growth stages of barnacle larvae, viz. nauplii stage II, nauplii stage IV and cyprids were exposed to the mentioned laser fluences for different durations. While lethal impact was assessed immediately after and 1 d after irradiation, sub‐lethal impacts were studied by monitoring the success rate of the irradiated nauplii in reaching the cyprid stage. In addition, the swimming speed of VI^th stage nauplii after irradiation was studied. In the case of cyprids, in addition to the mortality measurement immediately after and 1 d after irradiation, the settlement rate was investigated. In all the above experiments, non‐irradiated larvae served as controls. The results showed an increase in mortality with increasing laser fluence and duration of irradiation. Irradiation for 2 s resulted in significant mortality in nauplii, while it was less in the case of cyprids. In II^nd stage nauplii, the mortality immediately after irradiation for 2 s varied from 14.8±2.12 to 97.1±4.1% for laser fluences of 0.013 and 0.1 J cm^‐2, respectively. However, in cyprids, the mortality immediately after irradiation for 2 s varied from 12.2±3 to 13.4±1.2% for fluences of 0.013 and 0.1 J cm^‐2, respectively. The mortality in IV^th stage nauplii was less than that for II^nd stage nauplii but more than that for cyprids. There was a significant increase in mortality with time after irradiation. The formation of cyprids from the irradiated larvae was significantly less than that observed for non‐irradiated larvae. Also, the irradiated larvae showed a significantly slower swimming speed compared to the control samples. The settlement rate in cyprids was reduced significantly by the laser irradiation. This was true even for the lowest fluence and shortest period of irradiation tested. Thus, the results of the experiment showed that even a low power pulsed laser irradiation of 0.013 J cm^‐2 for 2 s can cause significant damage to fouling barnacle larvae.     

THE INFLUENCE OF ABDOMINAL PIGMENTATION ON DESICCATION AND ULTRAVIOLET RESISTANCE IN TWO SPECIES OF DROSOPHILA

Drosophila yakuba and D. santomea are sister species that differ in their levels of abdominal pigmentation; D. yakuba shows heavily pigmented posterior abdominal segments in both sexes, whereas D. santomea lacks dark pigment anywhere on its body. Using naturally collected lines, we demonstrate the existence of altitudinal variation in abdominal pigmentation in D. yakuba but not in D. santomea. We use the variation in pigmentation within D. yakuba and two body‐color mutants in D. yakuba to elucidate selective advantage of differences in pigmentation. Our results indicate that although differences in abdominal pigmentation have no effect on desiccation resistance, lighter pigmentation confers ultraviolet radiation resistance in this pair of species.     

Knockout of pgdS and ggt genes improves γ‐PGA yield in B. subtilis

One of the emerging biopolymers that are currently under active investigation is bacterial poly(γ‐glutamic acid) (γ‐PGA). However, before its full industrial exploitation, a substantial increase in microbial productivity is required. γ‐PGA obtained from the Bacillus subtilis laboratory strain 168 offers the advantage of a producer characterized by a well defined genetic framework and simple manipulation techniques. In this strain, the knockout of genes for the major γ‐PGA degrading enzymes, pgdS and ggt, leads to a considerable improvement in polymer yield, which attains levels analogous to the top wild γ‐PGA producer strains. This study highlights the convenience of using the laboratory strain of B. subtilis over wild isolates in designing strain improvement strategies aimed at increasing γ‐PGA productivity. Biotechnol. Bioeng. 2013; 110: 2006–2012. © 2013 Wiley Periodicals, Inc.