Lysosomal amino acid transporter LYAAT-1 in the rat central nervous system: An in situ hybridization and immunohistochemical study

A rat cDNA clone (pCD67) isolated from a cDNA library of regenerating sciatic nerve by differential hybridization screening revealed 75% homology on the nucleic acid level and 81% homology (including conservative amino acid changes) to the deduced amino acid sequence of the core protein of human dermatan/chondroitin sulfate proteoglycan decorin (PGII, PG40, PG-S2). Two transcripts of 1.3 and 1.75 KB very similar in size to the two decorin mRNA species previously identified in connective tissue were detected by Northern blotting in both normal and injured sciatic nerve and in the mature and embryonic rat brain. The steady-state level of the decorin 1.3 KB mRNA was very much higher in peripheral nerve than in the central nervous system or in other non-neural tissues (skeletal muscle, heart, colon, kidney). In situ hybridization experiments indicated that decorin mRNA is expressed by Schwann cells and vascular cells in peripheral nerve. In the spinal cord the ventral horn motor neurons and other neurons in gray matter showed specific hybridization signals. Furthermore, in situ hybridization indicated decorin expression in Purkinje neurons and cells of the molecular layer in cerebellum, and in neurons of the primary olfactory cortex and brainstem (pons). Our data clearly demonstrate decorin mRNA expression in distinct neural cell populations, suggesting yet unknown functions of this proteoglycan in the peripheral and central nervous system.

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Effects of central nervous system lesions on the expression of galanin: a comparative in situ hybridization and immunohistochemical study.

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.87.19.7742 ◽

1990 ◽

Vol 87 (19) ◽

pp. 7742-7746 ◽

Cited By ~ 52

Author(s):

R. Cortes ◽

M. J. Villar ◽

A. Verhofstad ◽

T. Hokfelt

Keyword(s):

Central Nervous System ◽

Nervous System ◽

In Situ Hybridization ◽

Immunohistochemical Study

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B0AT1 amino acid transporter complexed with SARS-CoV-2 receptor ACE2 forms a heterodimer functional unit: in situ conformation using radiation inactivation analysis

Function ◽

10.1093/function/zqab027 ◽

2021 ◽

Author(s):

Bruce R Stevens ◽

J Clive Ellory ◽

Robert L Preston

Keyword(s):

Amino Acid ◽

Membrane Trafficking ◽

Functional Unit ◽

Membrane Vesicles ◽

High Energy ◽

Amino Acid Transporter ◽

Neutral Amino Acid ◽

Transport Activity ◽

Acid Transporter

Abstract The SARS-CoV-2 receptor, Angiotensin Converting Enzyme-2 (ACE2), is expressed at levels of greatest magnitude in the small intestine as compared to all other human tissues. Enterocyte ACE2 is co-expressed as the apical membrane trafficking partner obligatory for expression and activity of the B0AT1 sodium-dependent neutral amino acid transporter. These components are assembled as an [ACE2: B0AT1]2 dimer-of-heterodimers quaternary complex that putatively steers SARS-CoV-2 tropism in the gastrointestinal (GI) tract. GI clinical symptomology is reported in about half of COVID-19 patients, and can be accompanied by gut shedding of virion particles. We hypothesized that within this 4-mer structural complex, each [ACE2: B0AT1] heterodimer pair constitutes a physiological “functional unit.” This was confirmed experimentally by employing purified lyophilized enterocyte brush border membrane vesicles that were exposed to increasing doses of high-energy electron radiation from a 16 MeV linear accelerator. Based on established target theory, the results indicated the presence of Na+-dependent neutral amino acid influx transport activity functional unit with target size mw = 183.7 ± 16.8 kDa in situ in intact apical membranes. Each thermodynamically stabilized [ACE2: B0AT1] heterodimer functional unit manifests the transport activity within the whole ∼345 kDa [ACE2: B0AT1]2 dimer-of-heterodimers quaternary structural complex. The results are consistent with our prior molecular docking modeling and gut-lung axis approaches to understanding COVID-19. These findings advance the understanding of the physiology of B0AT1 interaction with ACE2 in the gut, and thereby potentially contribute to translational developments designed to treat or mitigate COVID-19 variant outbreaks and/or GI symptom persistence in long-haul Post-Acute Sequelae of SARS-CoV-2 (PASC).

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Apoptotic Cells, Including Macrophages, Are Prominent in Theiler's Virus-Induced Inflammatory, Demyelinating Lesions

Journal of Virology ◽

10.1128/jvi.77.7.4383-4388.2003 ◽

2003 ◽

Vol 77 (7) ◽

pp. 4383-4388 ◽

Cited By ~ 41

Author(s):

Brian P. Schlitt ◽

Matthew Felrice ◽

Mary Lou Jelachich ◽

Howard L. Lipton

Keyword(s):

Central Nervous System ◽

T Cells ◽

Nervous System ◽

In Situ Hybridization ◽

Apoptotic Cells ◽

Theiler's Virus ◽

Demyelinating Lesions ◽

Encephalomyelitis Virus ◽

Mouse Central Nervous System

ABSTRACT Theiler's murine encephalomyelitis virus (TMEV) persists in the mouse central nervous system principally in macrophages, and infected macrophages in culture undergo apoptosis. We have detected abundant apoptotic cells in perivascular cuffs and inflammatory, demyelinating lesions of SJL mice chronically infected with TMEV. T cells comprised 74% of apoptotic cells, while 8% were macrophages, 0.6% were astrocytes, and ∼17% remained unidentified. In situ hybridization revealed viral RNA in ∼1% of apoptotic cells.

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