Novel benzimidazole-based MCH R1 antagonists

The identification of an MCH R1 antagonist screening hit led to the optimization of a class of benzimidazole-based MCH R1 antagonists. Structure-activity relationships and efforts to optimize pharmacokinetic properties are detailed along with the demonstration of the effectiveness of an MCH R1 antagonist in an animal model of obesity.     

The discovery and optimization of pyrimidinone-containing MCH R1 antagonists

Optimization of a series of constrained melanin-concentrating hormone receptor 1 (MCH R1) antagonists has provided compounds with potent and selective MCH R1 activity. Details of the optimization process are provided and the use of one of the compounds in an animal model of diet-induced obesity is presented.     

TGF-β1 as possible link between loss of bone mineral density and chronic inflammation

Background

The TGF family plays a key role in bone homeostasis. Systemic or topic application of proteins of this family apparently positively affects bone healing in vivo. However, patients with chronic inflammation, having increased TGF-β₁ serum-levels, often show reduced bone mineral content and disturbed bone healing. Therefore, we wanted to identify intracellular mechanisms induced by chronic presence of TGF-β₁ and their possible role in bone homeostasis in primary human osteoblasts.

Methodology/Principal Findings

Osteoblasts were isolated from femur heads of patients undergoing total hip replacement. Adenoviral reporter assays showed that in primary human osteoblasts TGF-β₁ mediates its signal via Smad2/3 and not Smad1/5/8. It induces proliferation as an intermediate response but decreases AP-activity and inorganic matrix production as a late response. In addition, expression levels of osteoblastic markers were strongly regulated (AP↓; Osteocalcin↓; Osteopontin↑; MGP↓; BMP 2↓; BSP2↓; OSF2↓; Osteoprotegerin↓; RANKL↑) towards an osteoclast recruiting phenotype. All effects were blocked by inhibition of Smad2/3 signaling with the Alk5-Inhibitor (SB431542). Interestingly, a rescue experiment showed that reduced AP-activities did not recover to base line levels, even 8 days after stopping the TGF-β₁ application.

Conclusions/Significance

In spite of the initial positive effects on cell proliferation, it is questionable if continuous Smad2/3 phosphorylation is beneficial for bone healing, because decreased AP-activity and BMP2 levels indicate a loss of function of the osteoblasts. Thus, inhibition of Smad2/3 phosphorylation might positively influence functional activity of osteoblasts in patients with chronically elevated TGF-β₁ levels and thus, could lead to an improved bone healing in vivo.     

Extraordinarily low evolutionary rates of short wavelength-sensitive opsin pseudogenes

Aquatic organisms such as cichlids, coelacanths, seals, and cetaceans are active in UV–blue color environments, but many of them mysteriously lost their abilities to detect these colors. The loss of these functions is a consequence of the pseudogenization of their short wavelength-sensitive (SWS1) opsin genes without gene duplication. We show that the SWS1 gene (Bden_S1ψ) of the deep-sea fish, pearleye (Benthalbella dentata), became a pseudogene in a similar fashion about 130 million years ago (Mya) yet it is still transcribed. The rates of nucleotide substitution (~ 1.4 × 10^− 9/site/year) of the pseudogenes of these aquatic species as well as some prosimian and bat species are much smaller than the previous estimates for the globin and immunoglobulin pseudogenes.     

Maternal Condition but Not Corticosterone Is Linked to Offspring Sex Ratio in a Passerine Bird

There is evidence of offspring sex ratio adjustment in a range of species, but the potential mechanisms remain largely unknown. Elevated maternal corticosterone (CORT) is associated with factors that can favour brood sex ratio adjustment, such as reduced maternal condition, food availability and partner attractiveness. Therefore, the steroid hormone has been suggested to play a key role in sex ratio manipulation. However, despite correlative and causal evidence CORT is linked to sex ratio manipulation in some avian species, the timing of adjustment varies between studies. Consequently, whether CORT is consistently involved in sex-ratio adjustment, and how the hormone acts as a mechanism for this adjustment remains unclear. Here we measured maternal baseline CORT and body condition in free-living blue tits (Cyanistes caeruleus) over three years and related these factors to brood sex ratio and nestling quality. In addition, a non-invasive technique was employed to experimentally elevate maternal CORT during egg laying, and its effects upon sex ratio and nestling quality were measured. We found that maternal CORT was not correlated with brood sex ratio, but mothers with elevated CORT fledged lighter offspring. Also, experimental elevation of maternal CORT did not influence brood sex ratio or nestling quality. In one year, mothers in superior body condition produced male biased broods, and maternal condition was positively correlated with both nestling mass and growth rate in all years. Unlike previous studies maternal condition was not correlated with maternal CORT. This study provides evidence that maternal condition is linked to brood sex ratio manipulation in blue tits. However, maternal baseline CORT may not be the mechanistic link between the maternal condition and sex ratio adjustment. Overall, this study serves to highlight the complexity of sex ratio adjustment in birds and the difficulties associated with identifying sex biasing mechanisms.     

Endotoxin inactivation via steam‐heat treatment in dilute simethicone emulsions used in biopharmaceutical processes

Simethicone emulsion is used to regulate foaming in cell culture operations in biopharmaceutical processes. It is also a potential source of endotoxin contamination. The inactivation of endotoxins in dilute simethicone emulsions was assessed as a function of time at different steam temperatures using a Limulus amebocyte lysate kinetic chromogenic technique. Endotoxin inactivation from steam‐heat treatment was fit to a four‐parameter double exponential decay model, which indicated that endotoxin inactivation was biphasic, consisting of fast and slow regimes. In the fast regime, temperature‐related effects were dominant. Transitioning into the slow regime, the observed temperature dependence diminished, and concentration‐related effects became increasingly significant. The change in the Gibbs free energy moving through the transition state indicated that a large energy barrier must be overcome for endotoxin inactivation to occur. The corresponding Arrhenius pre‐exponential factor was >>10¹² s^?1 suggesting that endotoxins in aqueous solution exist as aggregates. The disorder associated with the endotoxin inactivation reaction pathway was assessed via the change in entropy moving through the transition state. This quantity was positive indicating that endotoxin inactivation may result from hydrolysis of individual endotoxin molecules, which perturbs the conformation of endotoxin aggregates, thereby modulating the biological activity observed. Steam‐heat treatment decreased endotoxin levels by 1–2 logarithm (log) reduction (LRV), which may be practically relevant depending on incoming raw material endotoxin levels. Antifoam efficiency and cell culture performance were negligibly impacted following steam‐heat treatment. The results from this study show that steam‐heat treatment is a viable endotoxin control strategy that can be implemented to support large‐scale biopharmaceutical manufacturing. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:1145–1160, 2014