In vivo CHI3L1 (YKL-40) expression in astrocytes in acute and chronic neurological diseases.
BACKGROUND
CHI3L1 (YKL-40) is up-regulated in a variety of inflammatory conditions and cancers. We have previously reported elevated CHI3L1 concentration in the cerebrospinal fluid (CSF) of human and non-human primates with lentiviral encephalitis and using immunohistochemistry showed that CHI3L1 was associated with astrocytes.


METHODS
In the current study CHI3L1 transcription and expression were evaluated in a variety of acute and chronic human neurological diseases.


RESULTS
ELISA revealed significant elevation of CHI3L1 in the CSF of multiple sclerosis (MS) patients as well as mild elevation with aging. In situ hybridization (ISH) showed CHI3L1 transcription mostly associated with reactive astrocytes, that was more pronounced in inflammatory conditions like lentiviral encephalitis and MS. Comparison of CHI3L1 expression in different stages of brain infarction showed that YKL40 was abundantly expressed in astrocytes during acute phases and diminished to low levels in chronic infarcts.


CONCLUSIONS
Taken together, these findings demonstrate that CHI3L1 is induced in astrocytes in a variety of neurological diseases but that it is most abundantly associated with astrocytes in regions of inflammatory cells.
Bonneh-Barkay
Dafna
D
Department of Pathology, University of Pittsburgh, 200 Lothrop St, Pittsburgh, PA 15213, USA. bonnehbarkayd@upmc.edu
Wang
Guoji
G
Starkey
Adam
A
Hamilton
Ronald L
RL
Wiley
Clayton A
CA
D054392:Adipokines; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D000544:Alzheimer Disease / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D000690:Amyotrophic Lateral Sclerosis / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D000071451:Chitinase-3-Like Protein 1; D002908:Chronic Disease; D005260:Female; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D037102:Lectins / Q000235:genetics / Q000378:metabolism*; D008254:Macaca nemestrina; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D009422:Nervous System Diseases / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D020521:Stroke / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology
D054392:Adipokines; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D006023:Glycoproteins; D037102:Lectins