Prof Daniela Riccardi - PhD
1. To repurpose CaSR antagonists (calcilytics) as novel therapeutics for inflammatory lung disease;
2. To define the role of the CaSR in blood pressure control and in the prevention of vascular calcification;
3. To determine the role of the CaSR in fetal lung development;
4. To develop an in vitro human primary kidney cell model for studies of drug-induced kidney injury and mineral ion metabolism.
1. To repurpose CaSR antagonists (calcilytics) as novel therapeutics for inflammatory lung disease
The CaSR is a multimodal chemosensor (Figure 1). The expression of certain polycations (such as eosinophil cationic protein, major basic proteins, poly-L-arginine, spermine and spermidine), is increased in the serum and the sputum of asthmatic patients.Recently we have made the discovery that the CaSR is expressed in the airways, where activation of this receptor bypolycations drives airways hyperreactivity, bronchoconstriction and inflammation in allergic asthma. Excitingly, blocking the CaSR using “calcilytics”, drugs that were previously developed for osteoporosis, we could prevent all of these effects (Yarova et al, Science Translational Medicine 2015). Recent evidence suggests that calcilytics also prevent inflammation in pre-clinical COPD models (Yarova et al, unpublished observations). Oral calcilytics were initially developed as an anti-osteoporosis drug. While they were safe and well-tolerated in patients, their development was terminated due to lack of efficacy. Our goal is to raise venture capital for the repurposing existing calcilytics as novel therapeutics to treat inflammatory lung disorders in people.
Reference: Yarova et al. Sci Trans Med 284, ra60, 2015.
Collaborations: Dr Kidd, Dr Ford, Prof. Broadley, Prof Cockcroft (Cardiff University) and Profs CJ Corrigan and JPT Ward (King’s College London).
Funding: Asthma UK, the Cardiff Partnership Fund and the BBSRC.
2. To define the role of the CaSR in blood pressure control and in the prevention of vascular calcification
Disturbances in mineral ion metabolism result in altered CaSR expression or function. For instance, in the vasculature, where the CaSR is highly expressed under physiological conditions (Figure 2), loss of receptor expression in humans is associated with vascular calcification, a condition which is frequently described in patients with chronic kidney disease or diabetes mellitus (Figure 3). Using a model of targeted CaSR ablation from vascular smooth muscle cells, we have discovered that the loss of receptor expression results in hypotension and bradycardia, implicating the CaSR in the regulation of blood vessel tone. Furthermore, CaSR ablation from vascular smooth muscle cells leads to increased calcification in vitro, supporting a role for the receptor in mineral ion homeostasis.
Reference: Schepelmann et al, (2013). The vascular smooth muscle cell calcium-sensing receptor is involved in blood pressure regulation, calcium homeostasis and protection from calcification [Abstract]. JASN 24, 874A.
Collaborations: Prof Canfield and Dr Ward (Manchester University) and Dr Richards (Amgen Inc.).
Funding: BBSRC-Amgen studentship, the Marie Curie ITN “Multifaceted CaSR” and by a grant from Amgen, Inc.
3. To determine the role of calcium and of the CaSR in fetal lung development
In mammals, both total and free ionized calcium significantly exceed those measured in the adult (i.e., ~1.6 vs. ~1.2 mM). This relative fetal hypercalcaemia is preserved irrespectively of maternal serum calcium levels. The CaSR is responsible for maintaining this relative fetal hypercalcaemia, through the regulation of parathyroid hormone-related peptide secretion. Recently we have shown that the CaSR is highly expressed in the developing fetus, where it is involved in the regulation of growth and maturation of several organs/tissues, including, but not limited to, the lung and the peripheral nervous system. In the fetal lung, optimal lung development is a fine balance fluid secretion, branching morphogenesis and vascularisation. Impairment of any of these processes results in postnatal morbidity, which persists well into adulthood. Work carried out in the laboratory has demonstrated that fetal hypercalcaemia, acting in a CaSR-dependent and –independent manner, plays a key role in balancing branching morphogenesis with fluid secretion and vasculogenesis within the fetal lung (Figure 4).
References: Brennan et al, PLoS One. 2013 8(11):e80294; Riccardi et al, Best Pract Res Clin Endocrinol Metab. 2013;27(3):443-53.
Collaborations: Prof D Warburton (CHLA), Prof Canfield and Dr Ward (Manchester University) and Dr Richards (Amgen Inc.).
Funding: Marie Curie ITN “Multifaceted CaSR”.
4. To develop an in vitro human primary kidney cell model for studies of drug-induced kidney injury and mineral ion metabolism
Pre clinical in vivo drug testing in large Pharma only predicts toxicity in humans in ~50% of the cases, with significant delays in the drug discovery progress, human toxicity being detected in late stages of clinical trials and a large number of laboratory animals being killed un-necessarily. Current in vivo screenings fail because of species variation in the pharmaco- and toxico-kinetic profiles between rat and man, because of the identification of ‘false-positives’ in rat studies (which may lead to a promising drug which may have no toxicity in man being automatically being disregarded in pre-clinical studies), and because toxicity found in “first in man” studies is expensive at a late stage in the development pipeline. Established cell lines are also unsuitable to study drug-induced kidney injury since they do not retain the whole gamut of transporters and receptors typical of native kidney cells. We have successfully established human primary kidney proximal tubule cultures (from ethically consented nephrectomy specimens from patients undergoing surgery due to renal cell carcinoma), which represent a major leap forward to any currently cell-based standard approach.
We have validated this preparation through high-content studies and have demonstrated that this model recapitulates cellular toxicity events in humans, that it allows us to detect early damage to the kidney cells and that the damage correlates with the expression of known biomarkers of acute kidney injury (i.e., Kim1, clusterin and osteopontin) (Figure 5).
Importantly, this novel preparation provides us with both predictive and mechanistic interpretations of the type, cellular localization and extent of damage, potentially substantially improving drug safety profiles, significantly reducing both animal usage in drug testing and overall R&D costs. In contrast to established kidney cell lines, primary human kidney cells retain the morphological and functional properties of renal tissue in vivo and express key proteins involved in mineral ion homeostasis. These observations suggest that, in addition to being amenable for studies of drug-induced kidney toxicity, this novel preparation is suitable for studies of disturbances of mineral ion metabolism, an early event which takes place in the development of chronic kidney disease, a disease for which there is no cure and that affects ~10% of the population, worldwide
References: Wadey et al,. In vitro human renal primary cells for studies of mineral ion homeostasis [Abstract]. J. Amer.Soc. Nephrol, 2013, 24, 11A.
Collaborations: Dr Colin Brown (Newcastle University) and Dr Sally Price (AstraZeneca)
Funding: AstraZeneca & BBSRC.
Active Research Grants
- Ser Cymru
- British Heart Foundation
- NPS Pharmaceuticals, Inc.
Affiliated Lab Members
Dr Martin Schepelmann
Dr Polina Yarova
Dr Julia Griffiths
Postgraduate Research Students
Miss Irene Lopez
- Profs Paul J Kemp, Glyn Taylor, Drs Emma Kidd, Will Ford, Prof Ken Broadly, Dr A Brancale (asthma/COPD); Dr D Edwards and Prof J Cockroft (cardiovascular) (Cardiff University)
- Prof JPT Ward and CJ Corrigan (King’s College London)
- Dr Donald T Ward (Manchester University)
- Dr Sally A Price (Astra Zeneca, Macclesfield)
- Dr Wenhan Chang (UCSF, USA)
- Prof Eniko Kallay (Mediacl University of Vienna, Austria)
- Prof YS Prakash (Mayo Clinic, Rochester, USA)
- Dr Bill Richards (Amgen, USA)
- Dr David Warburton (CHLA, USA)