Fine Structure of Melanocytes and Macrophages in the Harderian Gland of the Mouse

Shirama, Kazuhiko; Harada, Tetsui; Kohda, Masanori; Hokano, Masami

doi:10.1159/000146512

Cited by 10 publications

(4 citation statements)

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“…The transcription factor MafB is expressed in pancreatic α cells, and it plays a role in embryonic urethral formation [ 9 , 16 , 44 , 45 , 46 ], MafB is also expressed in macrophages and regulates their differentiation [ 47 ]. In rodents, the HG is an important site of macrophage localization [ 21 ]. Even so, the expression and regulation of the MafB gene in the hamster HG remains largely unknown.…”

Section: Discussionmentioning

confidence: 99%

“…The HG is additionally characterized by the presence of mast cells, macrophages, and immunocompetent cells. Several studies have noted the presence of macrophages in HG [ 21 , 22 , 23 ]; the HG in hamsters ( Mesocricetus auratus ) exhibits a marked sexual dimorphism in terms of cell types, and it exhibits dimorphic features in porphyrins, fatty acids, indoleamines, and somatostatin biosynthesis that could be modified by sex steroids [ 19 ]. Androgens regulate these sex differences [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ].…”

Section: Introductionmentioning

confidence: 99%

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Dimorphic Regulation of the MafB Gene by Sex Steroids in Hamsters, Mesocricetus auratus

Ramos

2024

Animals

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MafB is a transcription factor that regulates macrophage differentiation. Macrophages are a traditional feature of the hamster Harderian gland (HG); however, studies pertaining to MafB expression in the HG are scant. Here, the full-length cDNA of the MafB gene in hamsters was cloned and sequenced. Molecular characterization revealed that MafB encodes a protein containing 323 amino acids with a DNA-binding domain, a transactivation domain, and a leucine zipper domain. qPCR assays indicated that MafB was expressed in different tissues of both sexes. The highest relative expression levels in endocrine tissues were identified in the pancreas. Gonadectomy in male hamsters was associated with significantly higher mRNA levels in the HG; replacement with dihydrotestosterone restored mRNA expression. The HG in male hamsters contained twofold more MafB mRNA than the HG of female hamsters. Adrenals revealed similar mRNA relative expression levels during the estrous cycle. The estrous phase was associated with higher mRNA levels in the ovary. A significantly up-regulated expression and sexual dimorphism of MafB was found in the pancreas. Therefore, MafB in the HG may play an active role in the macrophage differentiation required for phagocytosis activity and intraocular repair. Additionally, sex steroids appear to strongly influence the MafB expression in the HG and pancreas. These studies highlight the probable biological importance of MafB in immunological defense and pancreatic β cell regulation.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dimorphic Regulation of the MafB Gene by Sex Steroids in Hamsters, Mesocricetus auratus

Ramos

2024

Animals

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“…Several studies have noted the presence of macrophages in the rodent HG [21][22][23]; the HG in hamsters (Mesocricetus auratus) exhibits a marked sexual dimorphism in terms of cell types, and it exhibits dimorphic features in porphyrins, fatty acids, indoleamines, and somatostatin biosynthesis that could be modi ed by sex steroids [19]. Androgens regulate these sex differences [24][25][26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Dimorphic regulation of the MafB gene by sex steroids in hamsters (Mesocricetus auratus)

Ramos

2024

Preprint

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Background MafB is a transcription factor that regulates macrophage differentiation. Macrophages are a traditional feature of the hamster Harderian gland (HG); however, studies pertaining to MafB expression in the HG are scant. Here, I cloned and sequenced the full-length cDNA of the MafB gene in adult hamsters. Results Molecular characterization revealed that MafB encodes a protein containing 323 amino acids with a DNA-binding domain, a transactivation domain, and a leucine zipper domain. Bioinformatic analysis of the hamster MafB sequence demonstrated 98% consistency with the mammalian group, and quantitative real-time polymerase chain reaction assays indicated that MafB was expressed in different tissues of both sexes. The highest expression levels in endocrine tissues were identified in the pancreas. Gonadectomy in male hamsters was correlated with significantly higher mRNA levels in the HG; replacement with dihydrotestosterone (DHT) restored mRNA expression. The HG in male hamsters contained two-fold more MafB mRNA than the HG of female hamsters. Adrenals revealed similar mRNA expression levels during the estrous cycle. The estrous phase was correlated with higher mRNA levels in the ovary. Significantly up-regulated expression and sexual dimorphism of MafB was found in the pancreas. Conclusions MafB in the HG may play an active role in the macrophage differentiation required for phagocytosis activity and intraocular repair. Additionally, sex steroids appear to strongly influence the HG and MafB in the pancreas.

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“…The mouse HG appears to be speckled with dark-brown pigments due to porphyrin in the tubuloalveolar lumens and is dark grey due to melanocytes in the stroma [ 5 , 6 , 7 ]. There is no lobulation, no branched duct, and the lumens are wide.…”

Section: Introductionmentioning

confidence: 99%

Harderian Gland Development and Degeneration in the Fgf10-Deficient Heterozygous Mouse

Ikeda,

Sato,

Fujita

et al. 2024

JDB

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The mouse Harderian gland (HG) is a secretory gland that covers the posterior portion of the eyeball, opening at the base of the nictitating membrane. The HG serves to protect the eye surface from infection with its secretions. Mice open their eyelids at about 2 weeks of age, and the development of the HG primordium mechanically opens the eye by pushing the eyeball from its rear. Therefore, when HG formation is disturbed, the eye exhibits enophthalmos (the slit-eye phenotype), and a line of Fgf10+/− heterozygous loss-of-function mice exhibits slit-eye due to the HG atrophy. However, it has not been clarified how and when HGs degenerate and atrophy in Fgf10+/− mice. In this study, we observed the HGs in embryonic (E13.5 to E19), postnatal (P0.5 to P18) and 74-week-old Fgf10+/− mice. We found that more than half of the Fgf10+/− mice had markedly degenerated HGs, often unilaterally. The degenerated HG tissue had a melanized appearance and was replaced by connective tissue, which was observed by P10. The development of HGs was delayed or disrupted in the similar proportion of Fgf10+/− embryos, as revealed via histology and the loss of HG-marker expression. In situ hybridization showed Fgf10 expression was observed in the Harderian mesenchyme in wild-type as well as in the HG-lacking heterozygote at E19. These results show that the Fgf10 haploinsufficiency causes delayed or defective HG development, often unilaterally from the unexpectedly early neonatal period.

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Fine Structure of Melanocytes and Macrophages in the Harderian Gland of the Mouse

Cited by 10 publications

References 5 publications

Dimorphic Regulation of the MafB Gene by Sex Steroids in Hamsters, Mesocricetus auratus

Dimorphic Regulation of the MafB Gene by Sex Steroids in Hamsters, Mesocricetus auratus

Dimorphic regulation of the MafB gene by sex steroids in hamsters (Mesocricetus auratus)

Harderian Gland Development and Degeneration in the Fgf10-Deficient Heterozygous Mouse

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