Macrophage migration inhibitory factor expression is increased in pituitary adenoma cell nuclei

in Journal of Endocrinology
Authors:
ME Pyle
Search for other papers by ME Pyle in
Current site
Google Scholar
PubMed
Close
,
M Korbonits
Search for other papers by M Korbonits in
Current site
Google Scholar
PubMed
Close
,
M Gueorguiev
Search for other papers by M Gueorguiev in
Current site
Google Scholar
PubMed
Close
,
S Jordan
Search for other papers by S Jordan in
Current site
Google Scholar
PubMed
Close
,
B Kola
Search for other papers by B Kola in
Current site
Google Scholar
PubMed
Close
,
DG Morris
Search for other papers by DG Morris in
Current site
Google Scholar
PubMed
Close
,
A Meinhardt
Search for other papers by A Meinhardt in
Current site
Google Scholar
PubMed
Close
,
MP Powell
Search for other papers by MP Powell in
Current site
Google Scholar
PubMed
Close
,
FX Claret
Search for other papers by FX Claret in
Current site
Google Scholar
PubMed
Close
,
Q Zhang
Search for other papers by Q Zhang in
Current site
Google Scholar
PubMed
Close
,
C Metz
Search for other papers by C Metz in
Current site
Google Scholar
PubMed
Close
,
R Bucala
Search for other papers by R Bucala in
Current site
Google Scholar
PubMed
Close
, and
AB Grossman
Search for other papers by AB Grossman in
Current site
Google Scholar
PubMed
Close
Free access

Sign up for journal news

Macrophage migration inhibitory factor (MIF) is an essential regulator of the macrophage responses to endotoxin. MIF also has the ability to override the anti-inflammatory actions of glucocorticoids during an immune response, and is thus an important pro-inflammatory factor. The presence of MIF in cells of the anterior pituitary has been described, and high levels of MIF in other rapidly proliferating tIssues have also been demonstrated. It has been hypothesised that MIF release from these cells is influenced by the hypothalamo-pituitary-adrenal axis, and that ACTH and MIF are released simultaneously to exert counter-regulatory effects on cortisol. However, another intracellular role for MIF has also been suggested as it has been shown that MIF exerts an effect on the inhibitory cell cycle control protein p27 through an interaction with Jab1, a protein implicated in p27 degradation. We studied MIF expression in different normal and adenomatous human pituitary samples using immunohistochemistry and RT-PCR. There was evidence of co-immunoprecipitation of MIF with Jab1, suggesting an interaction of the two proteins. Our results showed that there is increased expression of MIF protein in the nuclei of all pituitary adenomas compared with normal tIssue (P=0.0067), but there was no statistically significant difference in nuclear MIF expression between the different adenoma types. Nuclear MIF expression correlated positively with p27 and its phosphorylated form in normal tIssue (P=0.0028 and P<0.0001); however, this relationship was not seen in the adenoma samples. Cytoplasmic expression of MIF was found to be variable both in normal and adenomatous samples, with no consistent pattern. MIF mRNA was demonstrated to be present in all tumour and normal samples studied. Somatotroph tumours showed higher MIF mRNA expression compared with normal pituitary or other types of adenomas. In conclusion, MIF is expressed in cell nuclei in pituitary adenomas to a greater extent than in normal pituitary tIssue. We speculate that it may play a role in the control of the cell cycle, but whether its higher level in adenomas is a cause or a consequence of the tumorigenic process remains to be clarified.