Change in Cationic Amino Acid Transport System and Effect of Lysine Pretreatment on Inflammatory State in Amyotrophic Lateral Sclerosis Cell Model

Abstract

Amyotrophic lateral sclerosis (ALS) is a lethal neurological disorder characterized by the deterioration of motor neurons. The aim of this study was to investigate alteration of cationic amino acid transporter (CAT-1) activity in the transport of lysine and the pretreatment effect of lysine on pro-inflammatory states in an amyotrophic lateral sclerosis cell line. The mRNA expression of cationic amino acid transporter 1 was lower in NSC-34/hSOD1 G93A (MT) than the control cell line (WT), lysine transport is mediated by CAT-1 in NSC-34 cell lines. The uptake of [ 3 H]L-lysine was Na + -independent, voltage-sensitive, and strongly inhibited by inhibitors and substrates of cationic amino acid transporter 1 (system y + ). The transport process involved two saturable processes in both cell lines. In the MT cell line, at a high-affinity site, the affinity was 9.4-fold higher and capacity 24-fold lower than that in the WT; at a low-affinity site, the capacity was 2.3-fold lower than that in the WT cell line. Donepezil and verapamil competitively inhibited [ 3 H]L-lysine uptake in the NSC-34 cell lines. Pretreatment with pro-inflammatory cytokines decreased the uptake of [ 3 H]L-lysine and mRNA expression levels in both cell lines; however, the addition of L-lysine restored the transport activity in the MT cell lines. L-Lysine exhibited neuroprotective effects against pro-inflammatory states in the ALS disease model cell lines. In conclusion, studying the alteration in the expression of transporters and characteristics of lysine transport in ALS can lead to the development of new therapies for neurodegenerative diseases.

Differences of Transport Activity of Arginine and Regulation on Neuronal Nitric Oxide Synthase and Oxidative Stress in Amyotrophic Lateral Sclerosis Model Cell Lines

“…Arginine is known to be transported by major four cationic amino acid transporters including system y + , b 0,+ , B 0,+ , and y + L. Previous studies have also shown that system y + is an arginine-specific transporter associated with several cell types, including neurons [ 30 , 36 , 37 , 38 ]. In our differential analysis ( Table 3 ), we found that system y + is primarily involved in arginine transport, and Slc7a1 is expressed in NSC-34 cell lines, as shown in our previous work [ 39 ]. Furthermore, our results suggest that system b 0,+ is involved, to a lesser extent, in L-arginine transport in MT and WT cell lines, although mRNA expression has not been observed in NSC-34 cell lines [ 39 ].…”

“…In our differential analysis ( Table 3 ), we found that system y + is primarily involved in arginine transport, and Slc7a1 is expressed in NSC-34 cell lines, as shown in our previous work [ 39 ]. Furthermore, our results suggest that system b 0,+ is involved, to a lesser extent, in L-arginine transport in MT and WT cell lines, although mRNA expression has not been observed in NSC-34 cell lines [ 39 ]. Earlier studies have showed L-arginine transport by both systems y + L and y + in human umbilical vein endothelial cells [ 40 ]; and in the uptake of arginine in the CAD cells [ 30 ], however, our data showed no involvement of system y + L in the MT cell lines, whereas only 3.4% involvement was observed in the WT cell lines.…”

“…The mRNA expression of SLC7a1 was depleted with oxidizing stress inducing agent H 2 O 2 and was recovered by lysine. [ 39 ]. Overall, these results suggest a neuroprotective effect of arginine in the ALS model cell lines, consistent with other studies showing the effective role of arginine [ 1 ], and outlines the relationship between the downregulation of CAT-1 arginine transporters under inflammatory conditions [ 8 ].…”

Blood–Brain Barrier Solute Carrier Transporters and Motor Neuron Disease

“…In our research work, we have compared the MT cell line with the WT cell line and together referred to them as ALS model cell lines. The procedure for the uptake in NSC-34 cells has been described in earlier studies [ 24 , 25 ]. Another cell model used in our previous research work is a BBB in vitro model.…”

Antioxidant and Neuroprotective Effects of Paeonol against Oxidative Stress and Altered Carrier-Mediated Transport System on NSC-34 Cell Lines

“…In a study on N-methyl-D-aspartate receptors, paeonol was shown to provide protection to neurons of the rat hippocampus against injury induced by the withdrawal of oxygen and glucose [ 17 ]. Our previous research showed the altered transport of various amino acids, for instance, citrulline, lysine, tryptophan, and acidic drugs, including 4-phenylbutyric acid and valproic acid [ 18 ], as well as the energy-metabolizing compound carnitine in an ALS model cell line [ 19 , 20 , 21 , 22 , 23 ]. Since paeonol had a neuroprotective effect on activated microglial cells and hippocampal neurons, we assumed that studying the transport of paeonol in NSC-34 cell lines would bring new insights into its role in ALS.…”