The role of C5a-C5aR1 axis in bone pathophysiology: A mini-review

Bone remodeling is a physiological, dynamic process that mainly depends on the functions of 2 cell types: osteoblasts and osteoclasts. Emerging evidence suggests that complement system is crucially involved in the regulation of functions of these cells, especially during inflammatory states. In this context, complement component 5a (C5a), a powerful pro-inflammatory anaphylatoxin that binds the receptor C5aR1, is known to regulate osteoclast formation and osteoblast inflammatory responses, and has thus been proposed as potential therapeutic target for the treatment of inflammatory bone diseases. In this review, we will analyze the role of C5a-C5aR1 axis in bone physiology and pathophysiology, describing its involvement in the pathogenesis of some of the most frequent inflammatory bone diseases such as rheumatoid arthritis, and also in osteoporosis and bone cancer and metastasis. Moreover, we will examine C5aR1-based pharmacological approaches that are available and have been tested so far for the treatment of these conditions. Given the growing interest of the scientific community on osteoimmunology, and the scarcity of data regarding the role of C5a-C5aR1 axis in bone pathophysiology, we will highlight the importance of this axis in mediating the interactions between skeletal and immune systems and its potential use as a therapeutic target.

Paclitaxel binds and activates C5aR1: A new potential therapeutic target for the prevention of chemotherapy-induced peripheral neuropathy and hypersensitivity reactions

Chemotherapy-induced peripheral neuropathy (CIPN) and hypersensitivity reactions (HSRs) are among the most frequent and impairing side effects of the antineoplastic agent paclitaxel. Here, we demonstrated that paclitaxel can bind and activate complement component 5a receptor 1 (C5aR1) and that this binding is crucial in the etiology of paclitaxel-induced CIPN and anaphylaxis. Starting from our previous data demonstrating the role of interleukin (IL)-8 in paclitaxel-induced neuronal toxicity, we searched for proteins that activate IL-8 expression and, by using the Exscalate platform for molecular docking simulations, we predicted the high affinity of C5aR1 with paclitaxel. By in vitro studies, we confirmed the specific and competitive nature of the C5aR1-paclitaxel binding and found that it triggers intracellularly the NFkB/P38 pathway and c-Fos. In F11 neuronal cells and rat dorsal root ganglia, C5aR1 inhibition protected from paclitaxel-induced neuropathological effects, while in paclitaxel-treated mice, the absence (knock-out mice) or the inhibition of C5aR1 significantly ameliorated CIPN symptoms-in terms of cold and mechanical allodynia-and reduced the chronic pathological state in the paw. Finally, we found that C5aR1 inhibition can counteract paclitaxel-induced anaphylactic cytokine release in macrophages in vitro, as well as the onset of HSRs in mice. Altogether these data identified C5aR1 as a key mediator and a new potential pharmacological target for the prevention and treatment of CIPN and HSRs induced by paclitaxel.

Discovery of Novel TRPM8 Blockers Suitable for the Treatment of Somatic and Ocular Painful Conditions: A Journey through pKa and LogD Modulation

Transient receptor potential melastatin 8 (TRPM8) is crucially involved in pain modulation and perception, and TRPM8 antagonists have been proposed as potential therapeutic approaches for pain treatment. Previously, we developed two TRPM8 antagonists and proposed them as drug candidates for topical and systemic pain treatment. Here, we describe the design and synthesis of these two TRPM8 antagonists (27 and 45) and the rational approach of modulation/replacement of bioisosteric chemical groups, which allowed us to identify a combination of narrow ranges of pK_a and LogD values that were crucial to ultimately optimize their potency and metabolic stability. Following the same approach, we then pursued the development of new TRPM8 antagonists suitable for the topical treatment of ocular painful conditions and identified two new compounds (51 and 59), N-alkoxy amide derivatives, that can permeate across ocular tissue and reduce the behavioral responses induced by the topical ocular menthol challenge in vivo.

A new synthetic dual agonist of GPR120/GPR40 induces GLP-1 secretion and improves glucose homeostasis in mice

G-protein coupled receptors 40 and 120 (GPR40 and GPR120) are increasingly emerging as potential therapeutic targets for the treatment of altered glucose homeostasis, and their agonists are under evaluation for their glucagon-like peptide-1 (GLP-1)-mediated therapeutic effects on insulin production and sensitivity. Here, we characterized a new dual GPR40 and GPR120 agonist (DFL23916) and demonstrated that it can induce GLP-1 secretion and improve glucose homeostasis. Resulting from a rational drug design approach aimed at identifying new dual GPR120/40 agonists able to delay receptor internalization, DFL23916 had a good activity and a very high selectivity towards human GPR120 (long and short isoforms) and GPR40, as well as towards their mouse orthologous, by which it induced both Gαq/11-initiated signal transduction pathways with subsequent Ca2+ intracellular spikes and G protein-independent signaling via β-arrestin with the same activity. Compared to the endogenous ligand alpha-linolenic acid (ALA), a selective GPR120 agonist (TUG-891) and a well-known dual GPR40 and GPR120 agonist (GW9508), DFL23916 was the most effective in inducing GLP-1 secretion in human and murine enteroendocrine cells, and this could be due to the delayed internalization of the receptor (up to 3 h) that we observed after treatment with DFL23916. With a good pharmacokinetic/ADME profile, DFL23916 significantly increased GLP-1 portal vein levels in healthy mice, demonstrating that it can efficiently induce GLP-1 secretion in vivo. Contrary to the selective GPR120 agonist (TUG-891), DFL23916 significantly improved also glucose homeostasis in mice undergoing an oral glucose tolerance test (OGTT).

Prediction of adverse perinatal outcome by cerebroplacental ratio adjusted for estimated fetal weight

OBJECTIVES

To evaluate the relationship between cerebroplacental ratio (CPR) and estimated fetal weight (EFW) in low- and high-risk singleton pregnancies. Furthermore, we evaluated the role of CPR in the prediction of adverse perinatal outcome and whether CPR measurements adjusted for EFW improve its predictive value.

METHODS

This was a retrospective cohort study including pregnancies in which Doppler investigations of umbilical artery (UA) and fetal middle cerebral artery (MCA) were performed at ≥ 30 weeks' gestation. Pregnancies were allocated to one of three groups according to EFW centile: small-for-gestational age (SGA) with EFW < 10^th centile, appropriate-for-gestational age (AGA) and large-for-gestational age (LGA) with EFW > 90^th centile. CPR was calculated as the ratio between the UA pulsatility index (PI) and MCA-PI and converted to CPR multiples of the median (MoMs) according to the three EFW groups. Linear regression analysis was performed to evaluate the relationship between CPR-MoMs and EFW centiles in low-risk pregnancies. Furthermore, MoMs of CPR adjusted according to EFW centile (aCPR-MoMs) were calculated. Adverse perinatal outcome was defined as presence of pathological cardiotocography (CTG) trace, arterial cord blood pH < 7.1, 5-min Apgar score < 7 and presence of meconium-stained amniotic fluid (MSAF).

RESULTS

A total of 3515 (3016 low risk and 499 high risk) pregnancies, delivered between January 2010 and March 2016, were included. Linear regression analysis revealed a significant positive correlation between EFW centile and CPR-MoM. Receiver-operating characteristics (ROC) curve analysis showed a significant association between CPR-MoM and pathological CTG trace (AUC, 0.539; SD, 0.014; P = 0.005) and low Apgar score (AUC, 0.609; SD, 0.041; P = 0.008), but not with low arterial pH or MSAF. There was a significant association between aCPR-MoM and pathological CTG trace (AUC, 0.540; SD, 0.014; P = 0.003), low arterial cord blood pH (AUC, 0.546; SD, 0.022; P = 0.035) and low Apgar score (AUC, 0.609; SD, 0.044; P = 0.008), but not with MSAF. However, detection rates for adverse perinatal outcomes by CPR-MoM and aCPR-MoM were low, ranging from 6.7% to 28.6% for SGA, 12.1% to 22.2% for AGA and 0% to 33.3% for LGA, for a false-positive rate of 10%. In a subgroup analysis of cases in which ultrasound examination was performed at ≥ 34 weeks of gestation and within 4 weeks of delivery (n = 1439), the ROC curves for aCPR-MoM were significantly associated with all four outcomes evaluated.

CONCLUSIONS

CPR-MoM values are dependent on EFW centiles; therefore, we suggest that CPR-MoM should be adjusted for EFW centile. However, both CPR- and aCPR-MoM showed a low prediction rate for adverse perinatal outcome. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

A composite enhancer regulates p63 gene expression in epidermal morphogenesis and in keratinocyte differentiation by multiple mechanisms

p63 is a crucial regulator of epidermal development, but its transcriptional control has remained elusive. Here, we report the identification of a long-range enhancer (p63LRE) that is composed of two evolutionary conserved modules (C38 and C40), acting in concert to control tissue- and layer-specific expression of the p63 gene. Both modules are in an open and active chromatin state in human and mouse keratinocytes and in embryonic epidermis, and are strongly bound by p63. p63LRE activity is dependent on p63 expression in embryonic skin, and also in the commitment of human induced pluripotent stem cells toward an epithelial cell fate. A search for other transcription factors involved in p63LRE regulation revealed that the CAAT enhancer binding proteins Cebpa and Cebpb and the POU domain-containing protein Pou3f1 repress p63 expression during keratinocyte differentiation by binding the p63LRE enhancer. Collectively, our data indicate that p63LRE is composed of additive and partly redundant enhancer modules that act to direct robust p63 expression selectively in the basal layer of the epidermis.

Are there any relationships between umbilical artery Pulsatility Index and macrosomia in fetuses of type I diabetic mothers?

OBJECTIVE

To establish whether there are relationships between umbilical artery Pulsatility Index (PI) and fetal macrosomia in pregnancies complicated by type I diabetes.

METHODS

In a retrospective observational study, 102 singleton pregnant women with type I diabetes were considered. Umbilical artery PI was measured by Doppler ultrasonography within one week from delivery and related to neonatal weight. Pregnancies were grouped according to birtweight in macrosomic group (≥4000 g) and normal growth group (<4000 g). Relationships between umbilical artery PI and birth weight and birth weight centile were tested by Pearson's correlation analysis. Further umbilical artery PI values were compared between macrosomic and normally grown fetuses.

RESULTS

Birth weight was ≥4000 g in 24 pregnancies (23.5%). A significant relationship was found between umbilical artery PI and neonatal weight (r = 0.512; p < 0.01) and neonatal weight centile (r = 0.400; p < 0.01). Umbilical artery PI were significantly lower (t = -6.013; p < 0.001) in the macrosomic group (0.78; 95% confidence interval (CI) 0.73-0.84) than in the normal growth group (1.00; 95% CI 0.97-1.04).

CONCLUSIONS

In pregnancies complicated by type I diabetes there is a significant relationship between umbilical artery PI value before delivery and absolute birth weight and birth weight centile. Macrosomic fetuses show a significant reduction in umbilical artery PI when compared with diabetic pregnancies without fetal overgrowth.