Expression of mitogen activated protein kinases in labial salivary glands of patients with Sjögren's syndrome.
OBJECTIVE
The expression of CD40 and CD40 ligand (CD40L) in mononuclear cells (MNCs) infiltrating the salivary glands of patients with Sjögren's syndrome (SS) has recently been reported. This study determined the expression of mitogen activated protein kinase (MAP kinase) superfamilies, which act as downstream effector molecules of CD40, in MNCs infiltrating labial salivary tissues in SS patients.


METHODS
Six HTLV-I seronegative SS patients and 10 HTLV-I seropositive patients including five HTLV-I associated myelopathy (HAM) patients were examined. The expression of MAP kinase superfamilies in labial salivary glands was examined by immunohistochemistry containing the mirror section technique.


RESULTS
Both active forms of c-Jun N-terminal kinase (JNK) and p38 were found in salivary infiltrating MNCs of SS patients. Only minimal expression of the active form of extracellular signal regulated kinase (ERK) was observed in these tissues, however, co-expression of active JNK and active p38 was confirmed by the mirror section technique. Furthermore, these protein kinases were co-expressed in CD40(+) MNCs. No difference in expression levels of active JNK and p38 was found in patients who were positive or negative for anti-HTLV-I antibody.


CONCLUSIONS
These results indicate that JNK and p38, but not ERK, function as downstream effector molecules of CD40 in salivary infiltrating MNCs in SS patients, and suggest that these molecules may be involved in the pathological process of chronic sialadenitis in SS.
Nakamura
H
H
First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan.
Kawakami
A
A
Yamasaki
S
S
Kawabe
Y
Y
Nakamura
T
T
Eguchi
K
K
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019013:CD40 Antigens / Q000032:analysis; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000032:analysis*; D004268:DNA-Binding Proteins; D005260:Female; D015490:HTLV-I Infections / Q000201:enzymology; D015368:Human T-lymphotropic virus 1; D006801:Humans; D007150:Immunohistochemistry; D048031:JNK Mitogen-Activated Protein Kinases; D008046:Lip; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases; D009687:Nuclear Proteins / Q000032:analysis; D016601:RNA-Binding Proteins; D012469:Salivary Glands / Q000201:enzymology*; D012859:Sjogren's Syndrome / Q000201:enzymology*
D019013:CD40 Antigens; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C095938:Pa2g4 protein, mouse; D016601:RNA-Binding Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases