A major advance in our understanding of acid-base homeostasis and ammonia metabolism is the identification that Rh glycoproteins are ammonia transporters. In the kidney, multiple lines of evidence suggest that Rh glycoprotein C Glycoprotein (Rhcg) is critically important in renal ammonia metabolism. A second advance has been the recognition that Rhcg is expressed in principal cells, a cell not generally known to be involved in acid-base homeostasis, and that principal cell Rhcg expression parallels ammonia excretion. Thus, principal cells may contribute to regulated transcellular ammonia secretion. Finally, Rhcg expression appears to be regulated through post-transcriptional mechanisms. The overall aim of this application is to determine Rhcg's role in acid-base homeostasis and in potassium homeostasis. The first goal is to determine the specific role of Rhcg in the renal response to metabolic acidosis. We will use Cre-loxP technology to generate transgenic mice with kidney-specific, intercalated cell-specific and principal cell-specific Rhcg deletion. We will then examine acid- base homeostasis in these mice under control conditions and in response to metabolic acidosis in order to determine the specific role of Rhcg in renal acid-base homeostasis, and the specific contributions of intercalated cells and principal cells to acid-base homeostasis.
Our second aim i s to determine Rhcg's specific role in the renal response to hypokalemia. We will again use Cre-loxP technology to generate transgenic mice with kidney- specific, intercalated cell-specific and principal cell-specific Rhcg deletion. We will then examine acid-base and potassium homeostasis in these mice under control conditions and in response to dietary potassium deficiency in order to determine the specific role of Rhcg in the renal response to hypokalemia, and the specific contributions of intercalated cells and principal cells to Rhcg-mediated ion transport in response to hypokalemia.
Acid-base disorders are associated with renal stone disease, osteoporosis, muscle atrophy, growth retardation and increased morbidity. The proposed studies will provide new insights into the fundamental mechanisms of acid-base homeostasis, thereby providing underpinnings for new and novel treatments.
|Lee, Hyun-Wook; Osis, Gunars; Harris, Autumn N et al. (2018) NBCe1-A Regulates Proximal Tubule Ammonia Metabolism under Basal Conditions and in Response to Metabolic Acidosis. J Am Soc Nephrol 29:1182-1197|
|Harris, Autumn N; Grimm, P Richard; Lee, Hyun-Wook et al. (2018) Mechanism of Hyperkalemia-Induced Metabolic Acidosis. J Am Soc Nephrol 29:1411-1425|
|Harris, Autumn N; Lee, Hyun-Wook; Osis, Gunars et al. (2018) Differences in renal ammonia metabolism in male and female kidney. Am J Physiol Renal Physiol 315:F211-F222|
|Lee, Hyun-Wook; Handlogten, Mary E; Osis, Gunars et al. (2017) Expression of sodium-dependent dicarboxylate transporter 1 (NaDC1/SLC13A2) in normal and neoplastic human kidney. Am J Physiol Renal Physiol 312:F427-F435|
|Weiner, I David (2017) Roles of renal ammonia metabolism other than in acid-base homeostasis. Pediatr Nephrol 32:933-942|
|Canales, Benjamin K; Smith, Jennifer A; Weiner, I David et al. (2017) Polymorphisms in Renal Ammonia Metabolism Genes Correlate With 24-Hour Urine pH. Kidney Int Rep 2:1111-1121|
|Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E et al. (2017) Proximal tubule glutamine synthetase expression is necessary for the normal response to dietary protein restriction. Am J Physiol Renal Physiol 313:F116-F125|
|Weiner, I David; Verlander, Jill W (2017) Ammonia Transporters and Their Role in Acid-Base Balance. Physiol Rev 97:465-494|
|Osis, Gunars; Handlogten, Mary E; Lee, Hyun-Wook et al. (2016) Effect of NBCe1 deletion on renal citrate and 2-oxoglutarate handling. Physiol Rep 4:|
|Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E et al. (2016) Proximal tubule-specific glutamine synthetase deletion alters basal and acidosis-stimulated ammonia metabolism. Am J Physiol Renal Physiol 310:F1229-42|
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