Related Experiment Video
Updated: Apr 25, 2026
MicroRNA In situ Hybridization for Formalin Fixed Kidney Tissues
Published on: November 30, 2013
Melatonin Receptor 1 and Melatonin Receptor 2 Expression During Human Kidney Development and Their Association with
Ann-Kathrin Schmitt1, Victoria Tjora1, Nela Kelam1,2
1Laboratory for Early Human Development, Department of Anatomy, Histology and Embryology, School of Medicine, University of Split, Šoltanska 2A, 21000 Split, Croatia.
Background/Objectives:
Growing evidence indicates that melatonin contributes to kidney development and function, while disruptions of fetal circadian signaling have been linked to congenital anomalies of the kidney and urinary tract (CAKUT). This study aimed to characterize the developmental and spatial expression patterns of melatonin receptors MTNR1A and MTNR1B in normal human fetal kidneys and in CAKUT phenotypes.
Methods:
This study analyzed 40 human fetal kidney specimens, including healthy controls and CAKUT cases (horseshoe kidneys, duplex kidneys, and dysplastic kidneys), obtained from spontaneous abortions and pregnancy terminations. Samples were classified into developmental phases Ph2-Ph4 according to established morphological criteria. Immunofluorescence staining was used to visualize MTNR1A and MTNR1B expression. Quantitative analysis was performed using ImageJ, measuring the fluorescence area percentage. Statistical comparisons were conducted using a two-way ANOVA.
Results:
In control kidneys, MTNR1A expression was predominantly observed in glomeruli and interstitial cells and showed a descending trend across developmental stages, whereas MTNR1B was localized to glomeruli and strongly to the apical membranes of tubules, particularly distal tubules, without substantial developmental variation. CAKUT phenotypes exhibited higher expression of both receptors compared to controls. Significant phase-dependent differences in MTNR1A expression were observed in horseshoe, duplex, and dysplastic kidneys. MTNR1B expression decreased across developmental stages in dysplastic kidneys and differed significantly between Ph3 and Ph4 in duplex kidneys. At Ph3, duplex kidneys showed the highest MTNR1B expression.
Conclusions:
Altered developmental expression patterns of MTNR1A and MTNR1B in CAKUT suggest an association between melatonin signaling and abnormal human kidney development.
Insights
Altered expression of melatonin receptors MTNR1A and MTNR1B in fetal kidneys with congenital anomalies of the kidney and urinary tract (CAKUT) suggests melatonin signaling impacts kidney development.
Area of Science:
- Developmental biology
- Endocrinology
- Nephrology
Background:
- Melatonin is crucial for kidney development and function.
- Disrupted fetal circadian signaling is linked to CAKUT.
- Melatonin receptors MTNR1A and MTNR1B roles in fetal kidney development are unclear.
Purpose of the Study:
- Characterize developmental and spatial expression of MTNR1A and MTNR1B.
- Compare expression in normal fetal kidneys versus CAKUT phenotypes.
Main Methods:
- Analyzed 40 human fetal kidneys (controls and CAKUT phenotypes).
- Classified samples into developmental phases Ph2-Ph4.
- Used immunofluorescence and ImageJ for quantitative analysis.
Main Results:
- MTNR1A expressed in glomeruli and interstitial cells; MTNR1B in glomeruli and tubules.
- CAKUT kidneys showed higher MTNR1A and MTNR1B expression than controls.
- Phase-dependent differences in MTNR1A and MTNR1B expression were observed in CAKUT kidneys.
Conclusions:
- Altered MTNR1A and MTNR1B developmental expression in CAKUT suggests melatonin signaling involvement.
- Findings link melatonin signaling pathways to abnormal human kidney development.
