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Prof Daniela Riccardi  -  PhD


Four are my main lines of research:

1. The role of the extracellular calcium-sensing receptor, CaSR, in the kidney-bone-vascular axis

2. The role of calcium and of the CaSR in fetal development

3. Establishment of an in vitro human primary kidney cell model for studies of drug-induced kidney toxicity and mineral ion metabolism

4. The role of EPO in respiratory adaptation (in collaboration with Prof PJ Kemp)

1. The role of the extracellular calcium-sensing receptor, CaSR, in the kidney-bone-vascular axis  

The role of the extracellular calcium-sensing receptor, CaSR, in the kidney-bone-vascular axisThe CaSR exhibits ligand-biased signalling

Mammalian cells sense and respond to changes in the extracellular environment, particularly in variations of the levels of calcium ions, nutrient, salinity and pH. Crucial in this process is the extracellular calcium-sensing receptor (CaSR). In my laboratory we are interested in understanding how the CaSR recognises and integrates multiple signals (Figure 1), the biological events downstream of receptor activation  (Figure 2) and in the cellular and molecular targets involved in the homeostatic responses, with specific focus on the kidney, bone and the vasculature.

In addition, 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 3), 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 4, in collaboration with Prof Canfield and Dr Ward at Manchester University and Dr Richards at Amgen, USA).  Using a model of targeted gene deletion of the CaSR from vascular smooth muscle cells, current work aims at investigating the role of this receptor in the control of blood pressure and in pathological vascular calcification (BBSRC-Amgen studentship and EU-funded project, Marie Curie ITN “Multifaceted CaSR” http://www.multifaceted-casr.org).

The CaSR is expressed in the blood vesselsCaSR expression is significantly reduced in pathological calcified areas of human vessels

 

2. The role of calcium and of the CaSR in fetal development

The role of calcium and of the CaSR in fetal development

In mammalian species, 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 my 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 5) (EU-funded project, Marie Curie ITN “Multifaceted CaSR” http://www.multifaceted-casr.org).

3. Establishment of an in vitro human primary kidney cell model for studies of drug-induced kidney toxicity and mineral ion metabolism

Human primary kidney cell model for studies of drug-induced kidney toxicity and mineral ion metabolism

In pharmaceutical companies, pre clinical, in vivo drug testing is largely based in rat, but in ~50% of the time it fails to predict toxicity in humans, 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. In collaboration with Dr Colin Brown at Newcastle University and Dr Sally Price at AstraZeneca, 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 (Figure 6).

Expression of the biomarker of acute kidney injury, Kim1, is increased in primary human kidney cells treated with the nephrotoxin cisplatin for 24 hours

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 7).

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 (AstraZeneca & BBSRC-funded project).

4. The role of EPO in respiratory adaptation (in collaboration with Prof PJ Kemp)

See Professor Kemp’s web site for this project description.

 

Major Research Grants

Affiliated Lab Members

Dr Sarah Brennan 

Dr Julia Griffiths

Dr Polina Yarova

Postgraduate Research Students 

Mr Joao Graca 

Miss Irene Lopez

Miss Rebecca Wadey  

Collaborators

National:
  • Profs Paul J Kemp and Glyn Taylor, Drs Emma Kidd and W Ford (Cardiff University)
  • Dr Sally A Price (Astra Zeneca, Macclesfield)
  • Prof Rajesh Thakker and Dr Fadil Hannan (Oxford University)
  • Dr Donald T Ward and Prof AE Canfield (Manchester University)
International:
  • Prof Dirk Adriaensen (University of Antwerp, Belgium)
  • Prof Maria Luisa Brandi (University of Florence, Italy)
  • Dr Wenhan Chang (UCSF, USA)
  • Prof Eniko Kallay (Mediacl University of Vienna, Austria)
  • Dr Romuald Mentaverri (Universite Picardie Jules Verne, Amiens, France)
  • Dr Maria Pia Rastaldi and Prof PG Messa (University of Milan, Italy)
  • Dr Bill Richards (Amgen, USA)