Changes in the Cerebrospinal Fluid and Plasma Lipidome in Patients with Rett Syndrome

Abstract

Rett syndrome (RTT) is defined as a rare disease caused by mutations of the methyl-CpG binding protein 2 (MECP2). It is one of the most common causes of genetic mental retardation in girls, characterized by normal early psychomotor development, followed by severe neurologic regression. Hitherto, RTT lacks a specific biomarker, but altered lipid homeostasis has been found in RTT model mice as well as in RTT patients. We performed LC-MS/MS lipidomics analysis to investigate the cerebrospinal fluid (CSF) and plasma composition of patients with RTT for biochemical variations compared to healthy controls. In all seven RTT patients, we found decreased CSF cholesterol levels compared to age-matched controls (n = 13), whereas plasma cholesterol levels were within the normal range in all 13 RTT patients compared to 18 controls. Levels of phospholipid (PL) and sphingomyelin (SM) species were decreased in CSF of RTT patients, whereas the lipidomics profile of plasma samples was unaltered in RTT patients compared to healthy controls. This study shows that the CSF lipidomics profile is altered in RTT, which is the basis for future (functional) studies to validate selected lipid species as CSF biomarkers for RTT.

Ultraviolet exposure regulates skin metabolome based on the microbiome

“…After addition of 1.25 mL deionized water and 10 min of additional overhead shaking, the mixture was centrifuged for 10 min at 1350 g (room temperature) and the upper phase was transferred to a new glass tube. The lower phase was re-extracted with 2 mL of the upper phase of MTBE/methanol/deionized water (10:3:2.5, v/v/v) and again the upper phase was collected, combined with the upper phase from the first extraction 24 , 25 . Finally, the upper phase was evaporated in a vacuum centrifuge (Thermo Fisher Scientific, Waltham, MA, USA) and dissolved in 500 µL chloroform/methanol (1:1, v/v) 24 , 25 .…”

“…The lower phase was re-extracted with 2 mL of the upper phase of MTBE/methanol/deionized water (10:3:2.5, v/v/v) and again the upper phase was collected, combined with the upper phase from the first extraction 24 , 25 . Finally, the upper phase was evaporated in a vacuum centrifuge (Thermo Fisher Scientific, Waltham, MA, USA) and dissolved in 500 µL chloroform/methanol (1:1, v/v) 24 , 25 . For negative measurement 90 µL aliquots were spiked with 86.3 µL internal standards (chloroform/methanol, 1:1,v/v) containing 12:0/13:0 PI, 17:0/20:4 PI, 14:1/17:0 PI, 21:0/22:6 PI, 12:0/13:0 PG, 17:0/20:4 PG, 14:1/17:0 PG, 21:0/22:6 PG (1.5 µM each) and CL-Mix LM 6003 (2.4 µM).…”

“…For negative measurement 90 µL aliquots were spiked with 86.3 µL internal standards (chloroform/methanol, 1:1,v/v) containing 12:0/13:0 PI, 17:0/20:4 PI, 14:1/17:0 PI, 21:0/22:6 PI, 12:0/13:0 PG, 17:0/20:4 PG, 14:1/17:0 PG, 21:0/22:6 PG (1.5 µM each) and CL-Mix LM 6003 (2.4 µM). The solvent was evaporated under a gentle stream of nitrogen and the sample reconstituted in the same volume of injection solvent isopropanol/chloroform/methanol (90:5:5, v/v/v) 24 , 25 . For positive measurement 2.1 µL aliquots were spiked with 127.7 µL internal standards (chloroform/methanol, 1:1, v/v) containing PC 12:0/13:0, PC 17:0/20:4, PC 14:1/17:0, PC 21:0/22:6 (1 µM each), PE 12:0/13:0, PE 17:0/20:4, PE 14:1/17:0, PE 21:0/22:6, PS 12:0/13:0, PS 17:0/20:4, PS 14:1/17:0, PS 21:0/22:6 (1.5 µM each),TG-Mix LM 6000 (4 µM each), LPC 17:1 (1 µM), SL-Mix LM6002 (1.5 µM each), CE 19:0 (12 µM), and cholesterol- d 7 (80 µM) and 36 µL of this mix were used for further processing.…”

Convergent cerebrospinal fluid proteomes and metabolic ontologies in humans and animal models of Rett syndrome

“…Thus, a possible mechanism to account for the decreased levels of HDL apolipoproteins in CSF is either a decreased production/ secretion by Mecp2 deficient glial cells or an increased clearance by cells that express HDL receptors in brain, such as neurons (Wellington and Frikke-Schmidt, 2016;Liu et al, 2010). We favor the decreased HDL production model as it can explain the observed increased cholesterol content in brain at postnatal day 56, despite decreased expression of cholesterol synthesis enzymes and decreased de novo cholesterol synthesis, as well as the decreased cholesterol content in the CSF of Rett syndrome cases (Buchovecky et al, 2013;Zandl-Lang et al, 2022). We postulate that decreased HDL lipoproteins levels in CSF may be a factor contributing to the accumulation of cholesterol in brain and the concurrent inhibition by product of cholesterol synthesis.…”

Lipidomics—Paving the Road towards Better Insight and Precision Medicine in Rare Metabolic Diseases

“…RS lacks a specific biomarker, but altered Chol and lipid metabolism has been found in a KO-mouse model, as well as in RS patients. Our group performed both targeted and untargeted LC-MS/MS metabolomics and lipidomics to investigate the CSF and plasma composition of patients with RS for biochemical variations compared to healthy controls [ 107 ]. We were able to show that patients in our study cohort had decreased Chol levels in the CSF compared to the controls.…”