Sex Differences in Central Expression and Effects of Brain-Derived Neurotrophic Factor

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1 Sex Differences in Central Expression and Effects of Brain-Derived Neurotrophic Factor Haifei Shi Department of Biology, Miami University International Conference on Endocrinology October 22, 14

2 Arcuate melanocortin system BDNF VMH + BDNF ARC Expenditure Intake 3V + POMC Lepr Leptin Xu, et al., Nat Neurosci 3 Komori, et al., Neuroscience 6 Wang, et al., AJP 7, 1

3 Transgenic mouse models BDNF conditional deficient mice Control Bdnf deficient Rios, et al., Mol Endocrinol 1

4 Estradiol regulates food intake VMH ARC Expenditure Intake 3V estradiol Asarian & Geary, Philos T Roy Soc B 6

5 BDNF in and the estrogen hypothalamus receptor alpha (ERα) in the hypothalamus BDNF ERα Arc VMH 1 µm 1 µm Xu, et al., Nat Neurosci 3 Shi Lab

6 Colocalization of ERα and BDNF in the VMH ER α: brown (DAB) BDNF: blue black (nickel-enhanced DAB) BDNF + ER α Shi Lab ERα: brown BDNF: blue Blurton-Jones, et al., J Comp Neurol 4

7 Potential regulation of BDNF by estradiol VMH BDNF ARC estrogen Expenditure Intake 3V POMC estradiol Leptin

8 Hypothesis: Central BDNF expression and action are regulated by estradiol. Q1: Is central BDNF expression regulated by estradiol? Q2: Is central BDNF action regulated by estradiol? VMH BDNF 3V ARC POMC estradiol Expenditure Intake Leptin

9 Hypothesis: Central BDNF expression and action are regulated by estradiol. Q1: Is central BDNF expression regulated by estradiol? Q2: Is central BDNF action regulated by estradiol? VMH BDNF Estradiol (E2; subcu) 3V ARC POMC Leptin estradiol Expenditure Intake Ovariectomy (OVX)

10 Q1: Is central BDNF expression regulated by estradiol? (1) Does ovariectomy (OVX) or estradiol (E2) replacement modulate VMH BDNF gene expression? Experiment groups Sham-Oil OVX-Oil ad lib OVX-Oil pairfeed (PF) (pairfeed to Sham-Oil) OVX-E2

11 Q1: Is central BDNF expression regulated by estradiol? (1) Does ovariectomy (OVX) or estradiol (E2) replacement modulate VMH BDNF gene expression? 3 Sham-Oil OVX-Oil OVX-Oil PF OVX-E Body weight (g) Plasma estradiol level (pg/ml) Sham-Oil OVX-Oil OVX-Oil PF OVX-E Days # Sham-Oil OVX-Oil OVX-E Days Food intake (g) Bdnf mrna level in VMH (% of Sham females) Sham-Oil OVX-Oil OVX-Oil PF OVX-E2 Zhu, Liu, et al., Horm Behav 14

12 Q1: Is central BDNF expression regulated by estradiol? (2) Do male and female rats have different BDNF expression? Does estrous cycle modulate VMH BDNF gene expression? Experiment groups (Ordered 1-week old male and female rats, sacrificed at 12-week of age) 25 Daily Food Intake Food Intake (g) Food intake (g) 1 Plasma estradiol level (pg/ml) Male Diestrus Proestrus Estrus Metestrus 1 Male D-P P-E E-M M-D 11 Diestrus Proestrus Estrus Metestrus Diestrus Dairy Body Weight Body weight (g) Male D-P P-E E-M M-D Body weight (g) Bdnf mrna level in VMH (% of male) Male Diestrus Proestrus Estrus Metestrus Diestrus Proestrus Estrus Metestrus Zhu, Liu, et al., Horm Behav 14; Liu, Zhu, et al., Physiol Behav 14

13 Summary 1 Q1: Is central BDNF expression regulated by estradiol? BDNF gene expression is regulated in an estradiol-sensitive manner. OVX decreases BDNF gene expression; reversed by estradiol replacement. Estrous female rats have greater BDNF expression than males. BDNF expression is dynamically regulated across estrous cycle with a temporal elevation at estrous phase.

14 Hypothesis: Central BDNF expression and action are regulated by estradiol. Q1: Is central BDNF expression regulated by estradiol? Q2: Is central BDNF action regulated by estradiol? VMH BDNF 3V Clegg, et al., Diabetes 6 de Souza, et al., Eur J Pharmacol 11 Gao, et al., Nat Med 7 ARC POMC Leptin estradiol Expenditure Intake

15 Q2: Is central BDNF action regulated by estradiol? (1) Is central BDNF s anorexic effect regulated by estradiol? Experiment groups Male-Oil Sham-Oil OVX-Oil ad lib OVX-Oil pairfeed (PF) (pairfeed to Sham-Oil Female) OVX-E2

16 Q2: Is central BDNF action regulated by estradiol? (1) Is central BDNF s anorexic effect regulated by estradiol? 6 4 Plasma Estradiol Levels Male Sham Female OVX-Oil Female OVX-Oil PF Female Baseline 24-Hour Food Intake Plasma E2 level (pg/ml) OVX-E2 Female Male Sham-Oil Female Sham-Oil OVX-Oil OVX-Oil PF OVX-E Baseline Body Weights Food Intake (g) Male Sham-Oil Female Sham-Oil OVX-Oil OVX-Oil PF OVX-E2 25 Body Weight (g) # Experiment procedure Light Dark Light Lights i3vt Lights out; 4-hour 24-hour On.1µg,.3µg food intake food intake BDNF or vehicle Zhu, Liu, et al., Horm Behav 14

17 Q2: Is central BDNF action regulated by estradiol? (1) Is central BDNF s anorexic effect regulated by estradiol? food intake (g) 4-hour 8 µg BDNF.1 µg BDNF 6.3 µg BDNF hour food intake (g) 24 µg BDNF 22.1 µg BDNF 18.3 µg BDNF Male Sham-Oil Female Sham-Oil Male Sham-Oil Female Sham-Oil Zhu, Liu, et al., Horm Behav 14

18 Q2: Is central BDNF action regulated by estradiol? (2) Does ovariectomy or estradiol replacement regulate BDNF s anorexic effect? 4-hour food int take (g) 6 µg BDNF.1 µg BDNF.3 µg BDNF 4 2 OVX-E2 OVX-Oil PF OVX-Oil 24-hour food in ntake (g) OVX-E2 OVX-Oil PF OVX-Oil µg BDNF.1 µg BDNF.3 µg BDNF Zhu, Liu, et al., Horm Behav 14

19 Q2: Is central BDNF action regulated by estradiol? (3) Is central BDNF s effect on energy expenditure different between males and females? Experiment procedure Light Dark Light Lights i3vt Lights out; 24-hour On.1µg energy expenditure BDNF or vehicle

20 12 Q2: Is central BDNF action regulated by estradiol? (3) Is central BDNF s effect on energy expenditure different between males and females? Male Rats VO2 ml/kg BW /min saline.1 µg BDNF Time (hour) VO2 ml/kg BW /min 4 saline.1 µg BDNF 3 1 Dark Light RQ 1. saline.1 µg BDNF Dark Light VO2 ml/kg BW /min saline.1 µg BDNF Time (hour) VO2 ml/kg BW /min Dark saline.1 µg BDNF Light RQ Dark Female Rats 1. saline.1 µg BDNF Light Liu, Zhu, Shen, Shi. Unpublished.

21 Summary 2 Q2: Is central BDNF s action regulated by estradiol? Estrous female rats respond to a lower dose of BDNF than male rats to reduce food intake. Estradiol-replaced OVX rats respond to a lower dose of BDNF than oil-injected OVX rats to reduce food intake. Central administration of a low dose (.1 µg) of BDNF increased energy expenditure in female but not male rats. Central administration of a low dose (.1 µg) of BDNF increased lipid oxidation during dark and light phases in females and only during light phase in males.

22 Conclusion Estradiol increases BDNF central expression and action. VMH BDNF ARC Expenditure Intake 3V POMC estradiol Leptin

23 Acknowledgement Graduate students: Zheng Zhu Xian Liu Minqian Shen Shiva Senthil-Kumar Funding: R15DK9823 Undergraduate students: Ashley Goudjo-Ako Sean Pugh Undergraduate research funding Summer research fellowship SDG4528