ABHD6 suppression promotes anti-inflammatory polarization of adipose tissue macrophages via 2-monoacylglycerol/PPAR signaling in obese mice

OBJECTIVE

Pro-inflammatory polarization of adipose tissue macrophages (ATMs) plays a critical role in the pathogenesis of obesity-associated chronic inflammation. However, little is known about the role of lipids in the regulation of ATMs polarity and inflammation in response to metabolic stress. Deletion of α/β-hydrolase domain-containing 6 (ABHD6), a monoacylglycerol (MAG) hydrolase, has been shown to protect against diet-induced obesity and insulin resistance.

METHODS

Here we investigated the immunometabolic role of macrophage ABHD6 in response to nutrient excess using whole-body ABHD6-KO mice and human and murine macrophage cell-lines treated with KT203, a selective and potent pharmacological ABHD6 inhibitor.

RESULTS

KO mice on high-fat diet showed lower susceptibility to systemic diet-induced inflammation. Moreover, in the setting of overnutrition, stromal vascular cells from gonadal fat of KO vs. control mice contained lower number of M1 macrophages and exhibited enhanced levels of metabolically activated macrophages (MMe) and M2 markers, oxygen consumption, and interleukin-6 (IL-6) release. Likewise, under in vitro nutri-stress condition, inhibition of ABHD6 in MMe-polarized macrophages attenuated the expression and release of pro-inflammatory cytokines and M1 markers and induced the upregulation of lipid metabolism genes. ABHD6-inhibited MMe macrophages showed elevated levels of peroxisome proliferator-activated receptors (PPARs) and 2-MAG species. Notably, among different MAG species, only 2-MAG treatment led to increased levels of PPAR target genes in MMe macrophages.

CONCLUSIONS

Collectively, our findings identify ABHD6 as a key component of pro-inflammatory macrophage activation in response to excess nutrition and implicate an endogenous macrophage lipolysis/ABHD6/2-MAG/PPARs cascade, as a lipid signaling and immunometabolic pathway, which favors the anti-inflammatory polarization of ATMs in obesity.

Total synthesis and antifungal evaluation of cyclic aminohexapeptides

The need for new therapies to treat systemic fungal infections continues to rise. Naturally occurring hexapeptide echinocandin B (1) has shown potent antifungal activity via its inhibition of the synthesis of beta-1,3 glucan, a key fungal cell wall component. Although this series of agents has been limited thus far based on their physicochemical characteristics, we have found that the synthesis of analogues bearing an aminoproline residue in the 'northwest' position imparts greatly improved water solubility (> 5 mg/mL). The synthesis and structure-activity relationships (SAR) based on whole cell and upon in vivo activity of the series of compounds are reported.

Design and preparation of cyclopeptamine antifungal agents

The lack of agents for infections caused by pathogenic fungi has demanded further investigation of a key lead structure which has shown promise, echinocandin B. In recent years, two analogs of this cyclic hexapeptide are proceeding through the clinic exhibiting proof of concept for the target of these drugs. This target, the ss-1,3-glucan synthesis complex, produces the majority of fungal cell wall glucan in many of the most pathogenic fungi such as Candida. A methodical structure-activity relationship review of several major fragments of these highly functionalized molecules is described. This information is useful for determination of the minimum functional/structural requirements for design of an optimal compound in this series. Analogs are presented with their accompanying whole cell antifungal activities.

Synthesis of 9-deoxo-4''-deoxy-6,9-epoxyerythromycin derivatives: novel and acid-stable motilides

In our quest toward the discovery of highly potent and acid-stable motilides, novel 4"-deoxy derivatives of 9-deoxo-6, 9-epoxyerythromycin were designed, synthesized, and evaluated for their gastrointestinal prokinetic activities. These compounds, in their 9R configuration, were more potent than their 6,9-enol ether homologues in inducing well-coordinated smooth muscle contractions in an in vitro rabbit duodenal assay: e.g., (9R), (8S)-9-deoxo-4"-deoxy-3'-N-desmethyl-3'-N-ethyl-6, 9-epoxyerythromycin A (10) and (9R), (8S)-9-deoxo-4"-deoxy-3'-N-desmethyl-3'-N-ethanol-6, 9-epoxyerythromycin A (15) had a pED50 of 8.54 and 8.11 compared to a pED50 of 7.22 for compound 2 (ABT-229). Reduction of the 6,9-enol ether, which was aimed at improving the acid stability, afforded the most stable motilides to date with t1/2 of 5.5 h for 10 and 15. Compounds 10 and 15 bind specifically to rabbit antral smooth muscle motilin receptors with pIC50 values of 8.52 and 8.70.

Cellular accumulation, localization, and activity of a synthetic cyclopeptamine in fungi

A novel synthetic cyclopeptamine, A172013, rapidly accumulated by passive diffusion into Candida albicans CCH442. Drug influx could not be totally facilitated by the membrane-bound target, beta-(1,3)-glucan synthase, since accumulation was unsaturable at drug concentrations up to 10 microg/ml (about 1.6 x 10(-7) molecules/cell), or 25x MIC. About 55 and 23% of the cell-incorporated drug was associated with the cell wall and protoplasts, respectively. Isolated microsomes contained 95% of the protoplast-associated drug, which was fully active against glucan synthesis in vitro. Drug (0.1 microg/ml) accumulation was rapid and complete after 5 min in several fungi tested, including a lipopeptide/cyclopeptamine-resistant strain of C. albicans (LP3-1). The compound penetrated to comparable levels in both yeast and hyphal forms of C. albicans, and accumulation in Aspergillus niger was 20% that in C. albicans. These data indicated that drug-cell interactions were driven by the amphiphilic nature of the compound and that the cell wall served as a major drug reservoir.

Risk factors related to age-associated hearing loss in the speech frequencies

This paper examines the relationship between several risk factors and the development of age-associated hearing loss in the speech frequencies. Hearing loss is defined as an average threshold level of 30 dB HL or greater at the frequencies of 0.5, 1, 2, and 3 kHz. Hearing thresholds from 0.5 to 8 kHz using a pulse-tone tracking procedure were collected on participants of the Baltimore Longitudinal study of Aging since 1965. A proportional hazards regression model was used to study the relationship between several risk factors that have previously been found to be associated with numerous health-related outcomes and the length of follow-up time until the occurrence of unilateral or bilateral hearing loss in a screened group of 531 men. Risk factors considered are age, blood pressure, and alcohol and cigarette consumption. After controlling for age, only systolic blood pressure showed a significant relationship with hearing loss in the speech frequencies (p < .05). Since blood pressure is a modifiable risk factor, these results suggest that preventing hypertension might contribute to an effective program for the prevention of apparent age-associated hearing loss.

Preclinical in vivo efficacy of two 9-dihydrotaxane analogues against human and murine tumours

Two 9-dihydrotaxane analogues were synthesised and tested for in vitro potency and in vivo efficacy against murine and human tumour xenografts in mice. The in vitro potency of 9-dihydrotaxol (9-DH-t) and 10-deacetyl-9-dihydrotaxol (10-DeAc-9-DH-t) was generally less than that of paclitaxel against human and murine tumour cells. However, both analogues were at least 20-fold more soluble than paclitaxel in water. The analogues yielded cure rates > or = 60% against human MX-1 solid tumour xenografts in mice, compared with a cure rate of 10% for mice treated with paclitaxel. Both of the analogues were more effective than paclitaxel for treatment of murine M109 solid tumour in mice. 10-DeAc-9-DH-t was as effective as paclitaxel against murine B16 ascites tumour, while 9-DH-t was less effective. Both 10-DeAc-9-DH-t and 9-DH-t were demonstrably less toxic than paclitaxel. At equal dosages 9-DH-t produced serum concentrations greater than paclitaxel, while 10-DeAc-9-DH-t yielded serum concentrations less than paclitaxel. However, the decrease in toxicity of 9-DH-t and 10-DeAc-9-DH-t allowed a 4-fold increase in daily dosage. These two 9-dihydrotaxane analogues yielded favourable preclinical data and demonstrated good potential for further development.

Synthesis of 4"-deoxy motilides: identification of a potent and orally active prokinetic drug candidate

As an approach to discovering highly potent motilides with oral activity, novel 4"-deoxy derivatives of 8,9-anhydroerythromycin 6,9-hemiacetal were designed, synthesized, and evaluated for their gastrointestinal prokinetic activities. These compounds were orders of magnitude more potent than their 4"-hydroxy analogs in inducing smooth muscle contractions in an in vitro rabbit duodenal assay. Removal of the 12-hydroxy group, which was aimed at improving oral bioavailability, also afforded further potentiation in in vitro activity, leading to the identification of 8,9-anhydro-4"-deoxy-3'-N-desmethyl-3'-N-ethylerythromycin B 6,9-hemiacetal (ABT-229) as a potential prokinetic drug. ABT-229 was > 300,000 times more potent than erythromycin in vitro and had 39% oral bioavailability in dog compared to its 4",12-dihydroxy congener (EM-523), which was only 400 times more potent than erythromycin and had relatively low (1.4%) oral bioavailability.

Antitumor activity of 9(R)-dihydrotaxane analogs

A novel reduced taxane, 13-acetyl-9(R)-dihydrobaccatin III (1) has been isolated from Taxus canadensis. The selective C-13 deacetylation of this isolate has allowed for the preparation of a wide variety of 9(R)-dihydrotaxane analogs. In general, this series has shown greater stability and water solubility than the 9-carbonyl series while retaining antimicrotubule and tumor cell cytotoxicity activities relative to taxol. Placement of polar functionalities at the C-7 position results in loss of activity whereas alkylation or acylation of either C-7 or C-9 hydroxyl groups ameliorate the activity.

Gender differences in a longitudinal study of age-associated hearing loss

Current studies are inconclusive regarding specific patterns of gender differences in age-associated hearing loss. This paper presents results from the largest and longest longitudinal study reported to date of changes in pure-tone hearing thresholds in men and women screened for otological disorders and noise-induced hearing loss. Since 1965, the Baltimore Longitudinal Study of Aging has collected hearing thresholds from 500 to 8000 Hz using a pulsed-tone tracking procedure. Mixed-effects regression models were used to estimate longitudinal patterns of change in hearing thresholds in 681 men and 416 women with no evidence of otological disease, unilateral hearing loss, or noise-induced hearing loss. The results show (1) hearing sensitivity declines more than twice as fast in men as in women at most ages and frequencies, (2) longitudinal declines in hearing sensitivity are detectable at all frequencies among men by age 30, but the age of onset of decline is later in women at most frequencies and varies by frequency in women, (3) women have more sensitive hearing than men at frequencies above 1000 Hz but men have more sensitive hearing than women at lower frequencies, (4) learning effects bias cross-sectional and short-term longitudinal studies, and (5) hearing levels and longitudinal patterns of change are highly variable, even in this highly selected group. These longitudinal findings document gender differences in hearing levels and show that age-associated hearing loss occurs even in a group with relatively low-noise occupations and with no evidence of noise-induced hearing loss.

Synthesis and biological evaluation of C-3'-modified analogs of 9(R)-dihydrotaxol

Taxol (1) is considered a most exciting new drug in cancer chemotherapy. The promising antitumor activity of 9(R)-dihydrotaxol (3) encouraged us to further explore the structure-activity relationship of this new member of the taxane family. Studies indicated that the C-13 side chain of taxol is indispensable for antitumor activity and that the natural substitution pattern of a 2'(R)-hydroxy and a 3'(S)-acylamino group might be optimal. However, relatively little is known about the effects of the 3'-phenyl ring on activity. The synthesis and biological evaluation of analogs of 3 modified at the C-3' position are described. This study revealed that the 3'-phenyl ring was not required for activity and identified several compounds which had equal or greater in vitro and in vivo activity than taxol.

Synthesis and antifungal activity of 1,3,2-benzodithiazole S-oxides

The preparation of 1,3,2-benzodithiazole S-oxide analogs exhibiting in vitro antifungal activity against several strains of Candida is described. For the preparation of derivatives bearing aromatic substituents, a novel electrophilic aromatic thiolation reaction was utilized which produced substituted aromatic 1,2-dithiol intermediates. The reactions of nucleophiles with the parent heterocyclic system have led to an efficient transamidation process which allows for the direct production of these analogs. The S-oxide bond exhibits poor stereochemical stability and has been found to epimerize under ambient conditions. The structure-activity data report that a side chain of greater than 10 carbons effects a loss in activity as does the placement of polar groups in this chain.

Synthesis and antitumor activity of structural analogues of the epipodophyllotoxins

Several ring-contracted analogues of the antitumor agent etoposide have been prepared. The synthesis of the simple indanyl system 3 is described along with two bicyclic systems of general structure 4 prepared through a stereoselective allylation of the keto-ester 6. A cis-fused lactone analogue 5, which is isomeric with the etoposide aglycone, has been synthesized via a dialkylation of the indene-2-carboxylate anion. Regiochemical and stereochemical results of these alkylations are described. The cytotoxicity of these derivatives toward several tumor cell lines is described and generally follows the structure-activity relationships known for the agent podophyllotoxin (2).

Synthesis and activity of nonhydrolyzable pseudomonic acid analogues

Several series of pseudomonic acid analogues have been prepared that incorporate modified functionalities in place of the C1-C3 alpha,beta-unsaturated ester group. The inhibition of isoleucyl-tRNA synthetase and the in vitro activity of these compounds against various Gram-positive and Gram-negative strains are described. Several derivatives showed enzyme inhibition equivalent to or better than that of methyl pseudomonate (3), while lacking the hydrolyzable ester group at C1. These analogues include the corresponding phenyl ketone and the ether 12. The long-chain ketone 24 exhibited similar in vitro activity as the parent ester.

An analysis of adult social spacing tendencies and related social interactions in a colony of spider monkeys (Ateles geoffroyi) at the San Francisco zoo

Observations on adult interindividual spacing and social interactions for 13 spider monkeys (Ateles geoffroyi) of an approximately 48 animal captive colony were made from mid-June through August 1972. In this analysis the interanimal distances, general activities, and social interactions per minute observation for each subject were compared for a sample of 7 sexually mature males and 6 sexually mature females. Association tendencies between members of the same sex were significantly high as were exchanges of the taxon-specific 'pectoral sniff and embrane" interactions and grooming. The direction and nature of agonistic interactions was predominantly intersexual and involved frequent attacks by single or multiple males against females. Comparisons with a feral population of spider monkeys (Ateles belzebuth) revealed marked similarities in spatial affinities and patterns of social interaction.