Source: UNIVERSITY OF CINCINNATI submitted to NRP
MECHANISMS OF HOMEOSTASIS IN BOVINE LACTATION
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
Reporting Frequency
Annual
Accession No.
0216842
Grant No.
2009-35206-05178
Cumulative Award Amt.
(N/A)
Proposal No.
2008-04301
Multistate No.
(N/A)
Project Start Date
Mar 1, 2009
Project End Date
Feb 28, 2011
Grant Year
2009
Program Code
[42.0]- Animal Growth and Nutrient Utilization
Recipient Organization
UNIVERSITY OF CINCINNATI
2600 CLIFTON AVE
CINCINNATI,OH 45220-2872
Performing Department
(N/A)
Non Technical Summary
The rationale for these studies is to develop a level of understanding of the serotonin feedback system in the cow udder that will be sufficient to design methods to improve lactation and prevent problems associated with the lactation cycle in dairy animals. While it has been known for centuries that the mammary gland adjusts milk production according to the demands of offspring or artificial milking practices, the serotonin system that we discovered a few years ago, using mouse genetic approaches, was the first chemical system that has been discovered in the mammary gland that performs these functions. This grant is to improve our knowledge of this system in the dairy cow. The overarching hypothesis is that serotonin interacts with multiple proteins (receptors) in the cow mammary gland, and by doing so it causes changes in both milk synthesis, and mammary gland cell survival. The sum of these effects accounts for feedback regulation of milk production. The aims of the current project are to decrease the level of expression of certain serotonin receptors in cow mammary gland cell cultures, and in mouse mammary gland tissue, to determine what effect decreasing these receptors has on milk production. We will also use genetic tactics to produce mice that make cow serotonin receptor proteins, and measure what effect the cow proteins have on milk production in the mouse. We expect that these experiments will show that different proteins (receptors) cause very specific changes in milk production or cell survival in the mammary gland. The impact of these studies will be to provide information that can be used to develop drug treatments or genetic selections, or molecular genetic alterations, that optimize the function of the cow mammary gland serotonin system.
Animal Health Component
10%
Research Effort Categories
Basic
90%
Applied
10%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
3053410100025%
3053410102025%
3053410104025%
3053410106025%
Goals / Objectives
The overall goal is to advance our understanding of a recently-discovered serotonin system that functions as a local regulatory feedback during lactation. We have three specific goals for this project period. First, we will study the consequences of suppressing the 5-HT receptor subtypes in bovine mammary cells using inhibitory RNA (RNAi) tactics. Secondly, we will make transgenic mice that express receptors that are "cow-specific" (5-HT1b, 5-HT2a). Inducible expression of these transgenes will allow us to test hypotheses regarding the consequences of the cow-specific 5-HTRs. Thirdly, we will develop validated approaches for suppressing serotonergic genes in vivo. We will optimize expression of virally-transduced genes delivered by teat injection in mice and cows, and perform proof-of-concept in vivo RNAi experiments in mouse mammary glands.
Project Methods
The first goal will use RNAi tactics in cell cultures. We will test cells in 3D cultures, and monitor expression of specific functional markers. We will test specific hypotheses for each receptor subtype based on preliminary pharmacological data. The second goal will use transgenic mice in which we express specific cow genes (5-HT1b and 5-HT2a) that are implicated in unique properties of the cow lactation cycle. The third goal will use virally-transduced recombinant genes to alter expression of 5-HT receptors in mice, followed by proof-of-concept viral infection of cow mammary gland cells so that we can prepare for future studies in which we manipulate cow 5-HT system genes by virally-mediated recombinant DNA tactics. These approaches will provide information regarding how the 5-HT system regulates lactation and involution, and will be used to design methods for improving dairy herd performance throughout the lactation cycle.

Progress 03/01/09 to 02/28/11

Outputs
OUTPUTS: This project discovered key features of mammary gland physiology during lactation and involution. During this grant period two key findings moved this knowledge base forward dramatically. First, we discovered that enhancing intramammary serotonin activity by several means (drugs that target various aspects of serotonin metabolism) accelerates involution-like changes. This has led to the concept that these manipulations can be implemented practically as dry-off enhancers. We have successfully competed for SBIR funding (via formation of an outside company) to develop this commercially. Secondly, we have discovered that the intramammary serotonin system is a key regulator of calcium homeostasis during lactation. This regulatory system operates through specific mediators (PTHrP, Runx2, RANK-L, etc.). Future studies will be required to understand the full in vivo implications of these discoveries. PARTICIPANTS: Nelson D. Horseman, Ph.D. Principal Investigator Robert J. Collier, Ph.D. Co-Investigator Ekta Yadav, Research Assistant TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Our project has opened an entirely new area of lactation biology. We have established that a monoamine (serotonin) regulates key aspects of lactation, including milk homeostasis and calcium homeostasis. These findings will have practical impacts on the dairy industry as they are implemented through specific drugs and other manipulations.

Publications

  • 1: Pai VP, Horseman ND. Multiple cellular responses to serotonin contribute to epithelial homeostasis. PLoS One. 2011 Feb 24;6(2):e17028. PubMed PMID: 21390323; PubMed Central PMCID: PMC3044750.
  • 2: Hernandez LL, Collier JL, Vomachka AJ, Collier RJ, Horseman ND. Suppression of lactation and acceleration of involution in the bovine mammary gland by a selective serotonin reuptake inhibitor. J Endocrinol. 2011 Apr;209(1):45-54. Epub 2011 Feb 9. PubMed PMID: 21307120.
  • 3: Marshall AM, Nommsen-Rivers LA, Hernandez LL, Dewey KG, Chantry CJ, Gregerson KA, Horseman ND. Serotonin transport and metabolism in the mammary gland modulates secretory activation and involution. J Clin Endocrinol Metab. 2010 Feb;95(2):837-46. Epub 2009 Dec 4. PubMed PMID: 19965920; PubMed Central PMCID: PMC2840848.
  • 4: Pai VP, Marshall AM, Hernandez LL, Buckley AR, Horseman ND. Altered serotonin physiology in human breast cancers favors paradoxical growth and cell survival. Breast Cancer Res. 2009;11(6):R81. Epub 2009 Nov 10. PubMed PMID: 19903352; PubMed Central PMCID: PMC2815543.
  • 5: Hernandez LL, Limesand SW, Collier JL, Horseman ND, Collier RJ. The bovine mammary gland expresses multiple functional isoforms of serotonin receptors. J Endocrinol. 2009 Oct;203(1):123-31. Epub 2009 Aug 4. PubMed PMID: 19654143; PubMed Central PMCID: PMC2741409.