Renal sulfatides: sphingoid base-dependent localization and region-specific compensation of CerS2-dysfunction

Christian Marsching,Mariona Rabionet,Daniel Mathow,Richard Jennemann,Christiane Kremser,Stefan Porubsky,Christian Bolenz,Klaus Willecke,Hermann-Josef Gröne,Carsten Hopf,Roger Sandhoff

doi:10.1194/jlr.m051839

Abstract

Mammalian kidneys are rich in sulfatides. Papillary sulfatides, especially, contribute to renal adaptation to chronic metabolic acidosis. Due to differences in their cer-amide (Cer) anchors, the structural diversity of renal sulfatides is large. However, the underling biological function of this complexity is not understood. As a compound's function and its tissue location are intimately connected, we analyzed individual renal sulfatide distributions of control and Cer synthase 2 (CerS)2-deficient mice by imaging MS (IMS) and by LC-MS(2) (in controls for the cortex, medulla, and papillae separately). To explain locally different structures, we compared our lipid data with regional mRNA levels of corresponding anabolic enzymes. The combination of IMS and in source decay-LC-MS(2) analyses revealed exclusive expression of C20-sphingosine-containing sulfatides within the renal papillae, whereas conventional C18-sphingosine-containing compounds were predominant in the medulla, and sulfatides with a C18-phytosphingosine were restricted to special cortical structures. CerS2 deletion resulted in bulk loss of sulfatides with C23/C24-acyl chains, but did not lead to decreased urinary pH, as previously observed in sulfatide-depleted kidneys. The reasons may be the almost unchanged C22-sulfatide levels and constant total renal sulfatide levels due to compensation with C16- to C20-acyl chain-containing compounds. Intriguingly, CerS2-deficient kidneys were completely depleted of phytosphingosine-containing cortical sulfatides without any compensation.

Highlights

In correlation with the LC-MS2 data, signals for corresponding a sphingosine (AS)-lactosylceramide II3-sulfate (SM3) were below detection limits in normal kidneys by imaging MS (IMS), which is in contrast to data obtained from kidneys of the storage disease ASAϪ/Ϫ mouse [36]
Sulfatides with nonhydroxy fatty acid moieties N-linked to sphingosines (NSSM4s and NS-SM3) were most abundant in the papillae, but almost undetectable in the cortex (Fig. 2)
Using MALDI IMS for the histological analysis of renal sulfatides, we discovered special sulfatides with a C44-Cer anchor as highly concentrated markers of the papillary region

Summary

Introduction

Due to differences in their ceramide (Cer) anchors, the structural diversity of renal sulfatides is large. As a compound’s function and its tissue location are intimately connected, we analyzed individual renal sulfatide distributions of control and Cer synthase 2 (CerS)2-deficient mice by imaging MS (IMS) and by LC-MS2 (in controls for the cortex, medulla, and papillae separately). The combination of IMS and in source decay-LC-MS2 analyses revealed exclusive expression of C20-sphingosine-containing sulfatides within the renal papillae, whereas conventional C18-sphingosinecontaining compounds were predominant in the medulla, and sulfatides with a C18-phytosphingosine were restricted to special cortical structures. CerS2-deficient kidneys were completely depleted of phytosphingosine-containing cortical sulfatides without any compensation.—Marsching, C., M.

Methods

Results

Conclusion