Drug discovery for male subfertility using high-throughput screening: a new approach to an unsolved problem

Sarah J. Martins da Silva, Sean G. Brown, Keith Sutton, Louise V. King, Halil Ruso, David W. Gray, Paul G. Wyatt, Mark C. Kelly, Christopher L. R. Barratt, Anthony G. Hope

Research output: Contribution to journalArticle

Abstract

STUDY QUESTION: Can pharma drug discovery approaches be utilized to transform investigation into novel therapeutics for maleinfertility? SUMMARY ANSWER: High-throughput screening (HTS) is a viable approach to much-needed drug discovery for male factor infertility. WHAT IS KNOWN ALREADY: There is both huge demand and a genuine clinical need for new treatment options for infertile men. However, the time, effort and resources required for drug discovery are currently exorbitant, due to the unique challenges of the cellular, physical and functional properties of human spermatozoa and a lack of appropriate assay platform. STUDY DESIGN, SIZE, DURATION: Spermatozoa were obtained from healthy volunteer research donors and subfertile patients undergoing IVF/ICSI at a hospital-assisted reproductive techniques clinic between January 2012 and November 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: A HTS assay was developed and validated using intracellular calcium ([Ca2+]i) as a surrogate for motility in human spermatozoa. Calcium fluorescence was detected using a Flexstation microplate reader (384-well platform) and compared with responses evoked by progesterone, a compound known to modify a number of biologically relevant behaviours in human spermatozoa. Hit compounds identified following single point drug screen (10 μM) of an ion channel-focussed library assembled by the University of Dundee Drug Discovery Unit were rescreened to ensure potency using standard 10 point half-logarithm concentration curves, and tested for purity and integrity using liquid chromatography and mass spectrometry. Hit compounds were grouped by structure activity relationships and five representative compounds then further investigated for direct effects on spermatozoa, using computer-assisted sperm assessment, sperm penetration assay and whole-cell patch clamping. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 3242 ion channel library ligands screened, 384 compounds (11.8%) elicited a statistically significant increase in calcium fluorescence, with greater than 3× median absolute deviation above the baseline. Seventy-four compounds eliciting ≥50% increase in fluorescence in the primary screen were rescreened and evaluated further, resulting in 48 hit compounds that produced a concentration-dependent increase in [Ca2+]i. Sperm penetration studies confirmed in vitro exposure to two hit compounds (A and B) resulted in significant improvement in functional motility in spermatozoa from healthy volunteer donors (A: 1 cm penetration index 2.54, 2 cm penetration index 2.49; P < 0.005 and B: 1 cm penetration index 2.1, 2 cm penetration index 2.6; P < 0.005), but crucially, also in patient samples from those undergoing fertility treatment (A: 1 cm penetration index 2.4; P = 0.009, 2 cm penetration index 3.6; P = 0.02 and B: 1 cm penetration index 2.2; P = 0.0004, 2 cm penetration index 3.6; P = 0.002). This was primarily as a result of direct or indirect CatSper channel action, supported by evidence from electrophysiology studies of individual sperm. LIMITATIONS, REASONS FOR CAUTION: Increase and fluxes in [Ca2+]i are fundamental to the regulation of sperm motility and function, including acrosome reaction. The use of calcium signalling as a surrogate for sperm motility is acknowledged as a potential limitation in this study
Original languageEnglish
Pages (from-to)974-984
Number of pages11
JournalHuman Reproduction
Volume32
Issue number5
DOIs
StatePublished - 16 Mar 2017

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Male Infertility
Drug Discovery
Spermatozoa
Fluorescence
Calcium
Sperm-Ovum Interactions
Sperm Motility
Ion Channels
Healthy Volunteers
High-Throughput Screening Assays
Acrosome Reaction
Assisted Reproductive Techniques
Calcium Signaling
Intracytoplasmic Sperm Injections
Electrophysiology
Structure-Activity Relationship
Constriction
Liquid Chromatography
Progesterone
Fertility

Cite this

Martins da Silva, S. J., Brown, S. G., Sutton, K., King, L. V., Ruso, H., Gray, D. W., ... Hope, A. G. (2017). Drug discovery for male subfertility using high-throughput screening: a new approach to an unsolved problem. Human Reproduction, 32(5), 974-984. DOI: 10.1093/humrep/dex055

Martins da Silva, Sarah J.; Brown, Sean G.; Sutton, Keith; King, Louise V.; Ruso, Halil; Gray, David W.; Wyatt, Paul G.; Kelly, Mark C.; Barratt, Christopher L. R.; Hope, Anthony G. / Drug discovery for male subfertility using high-throughput screening : a new approach to an unsolved problem.

In: Human Reproduction, Vol. 32, No. 5, 16.03.2017, p. 974-984.

Research output: Contribution to journalArticle

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abstract = "STUDY QUESTION: Can pharma drug discovery approaches be utilized to transform investigation into novel therapeutics for maleinfertility? SUMMARY ANSWER: High-throughput screening (HTS) is a viable approach to much-needed drug discovery for male factor infertility. WHAT IS KNOWN ALREADY: There is both huge demand and a genuine clinical need for new treatment options for infertile men. However, the time, effort and resources required for drug discovery are currently exorbitant, due to the unique challenges of the cellular, physical and functional properties of human spermatozoa and a lack of appropriate assay platform. STUDY DESIGN, SIZE, DURATION: Spermatozoa were obtained from healthy volunteer research donors and subfertile patients undergoing IVF/ICSI at a hospital-assisted reproductive techniques clinic between January 2012 and November 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: A HTS assay was developed and validated using intracellular calcium ([Ca2+]i) as a surrogate for motility in human spermatozoa. Calcium fluorescence was detected using a Flexstation microplate reader (384-well platform) and compared with responses evoked by progesterone, a compound known to modify a number of biologically relevant behaviours in human spermatozoa. Hit compounds identified following single point drug screen (10 μM) of an ion channel-focussed library assembled by the University of Dundee Drug Discovery Unit were rescreened to ensure potency using standard 10 point half-logarithm concentration curves, and tested for purity and integrity using liquid chromatography and mass spectrometry. Hit compounds were grouped by structure activity relationships and five representative compounds then further investigated for direct effects on spermatozoa, using computer-assisted sperm assessment, sperm penetration assay and whole-cell patch clamping. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 3242 ion channel library ligands screened, 384 compounds (11.8%) elicited a statistically significant increase in calcium fluorescence, with greater than 3× median absolute deviation above the baseline. Seventy-four compounds eliciting ≥50% increase in fluorescence in the primary screen were rescreened and evaluated further, resulting in 48 hit compounds that produced a concentration-dependent increase in [Ca2+]i. Sperm penetration studies confirmed in vitro exposure to two hit compounds (A and B) resulted in significant improvement in functional motility in spermatozoa from healthy volunteer donors (A: 1 cm penetration index 2.54, 2 cm penetration index 2.49; P < 0.005 and B: 1 cm penetration index 2.1, 2 cm penetration index 2.6; P < 0.005), but crucially, also in patient samples from those undergoing fertility treatment (A: 1 cm penetration index 2.4; P = 0.009, 2 cm penetration index 3.6; P = 0.02 and B: 1 cm penetration index 2.2; P = 0.0004, 2 cm penetration index 3.6; P = 0.002). This was primarily as a result of direct or indirect CatSper channel action, supported by evidence from electrophysiology studies of individual sperm. LIMITATIONS, REASONS FOR CAUTION: Increase and fluxes in [Ca2+]i are fundamental to the regulation of sperm motility and function, including acrosome reaction. The use of calcium signalling as a surrogate for sperm motility is acknowledged as a potential limitation in this study",
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Martins da Silva, SJ, Brown, SG, Sutton, K, King, LV, Ruso, H, Gray, DW, Wyatt, PG, Kelly, MC, Barratt, CLR & Hope, AG 2017, 'Drug discovery for male subfertility using high-throughput screening: a new approach to an unsolved problem' Human Reproduction, vol 32, no. 5, pp. 974-984. DOI: 10.1093/humrep/dex055

Drug discovery for male subfertility using high-throughput screening : a new approach to an unsolved problem. / Martins da Silva, Sarah J.; Brown, Sean G.; Sutton, Keith; King, Louise V.; Ruso, Halil; Gray, David W.; Wyatt, Paul G.; Kelly, Mark C.; Barratt, Christopher L. R.; Hope, Anthony G.

In: Human Reproduction, Vol. 32, No. 5, 16.03.2017, p. 974-984.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Drug discovery for male subfertility using high-throughput screening

T2 - Human Reproduction

AU - Martins da Silva,Sarah J.

AU - Brown,Sean G.

AU - Sutton,Keith

AU - King,Louise V.

AU - Ruso,Halil

AU - Gray,David W.

AU - Wyatt,Paul G.

AU - Kelly,Mark C.

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AU - Hope,Anthony G.

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N2 - STUDY QUESTION: Can pharma drug discovery approaches be utilized to transform investigation into novel therapeutics for maleinfertility? SUMMARY ANSWER: High-throughput screening (HTS) is a viable approach to much-needed drug discovery for male factor infertility. WHAT IS KNOWN ALREADY: There is both huge demand and a genuine clinical need for new treatment options for infertile men. However, the time, effort and resources required for drug discovery are currently exorbitant, due to the unique challenges of the cellular, physical and functional properties of human spermatozoa and a lack of appropriate assay platform. STUDY DESIGN, SIZE, DURATION: Spermatozoa were obtained from healthy volunteer research donors and subfertile patients undergoing IVF/ICSI at a hospital-assisted reproductive techniques clinic between January 2012 and November 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: A HTS assay was developed and validated using intracellular calcium ([Ca2+]i) as a surrogate for motility in human spermatozoa. Calcium fluorescence was detected using a Flexstation microplate reader (384-well platform) and compared with responses evoked by progesterone, a compound known to modify a number of biologically relevant behaviours in human spermatozoa. Hit compounds identified following single point drug screen (10 μM) of an ion channel-focussed library assembled by the University of Dundee Drug Discovery Unit were rescreened to ensure potency using standard 10 point half-logarithm concentration curves, and tested for purity and integrity using liquid chromatography and mass spectrometry. Hit compounds were grouped by structure activity relationships and five representative compounds then further investigated for direct effects on spermatozoa, using computer-assisted sperm assessment, sperm penetration assay and whole-cell patch clamping. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 3242 ion channel library ligands screened, 384 compounds (11.8%) elicited a statistically significant increase in calcium fluorescence, with greater than 3× median absolute deviation above the baseline. Seventy-four compounds eliciting ≥50% increase in fluorescence in the primary screen were rescreened and evaluated further, resulting in 48 hit compounds that produced a concentration-dependent increase in [Ca2+]i. Sperm penetration studies confirmed in vitro exposure to two hit compounds (A and B) resulted in significant improvement in functional motility in spermatozoa from healthy volunteer donors (A: 1 cm penetration index 2.54, 2 cm penetration index 2.49; P < 0.005 and B: 1 cm penetration index 2.1, 2 cm penetration index 2.6; P < 0.005), but crucially, also in patient samples from those undergoing fertility treatment (A: 1 cm penetration index 2.4; P = 0.009, 2 cm penetration index 3.6; P = 0.02 and B: 1 cm penetration index 2.2; P = 0.0004, 2 cm penetration index 3.6; P = 0.002). This was primarily as a result of direct or indirect CatSper channel action, supported by evidence from electrophysiology studies of individual sperm. LIMITATIONS, REASONS FOR CAUTION: Increase and fluxes in [Ca2+]i are fundamental to the regulation of sperm motility and function, including acrosome reaction. The use of calcium signalling as a surrogate for sperm motility is acknowledged as a potential limitation in this study

AB - STUDY QUESTION: Can pharma drug discovery approaches be utilized to transform investigation into novel therapeutics for maleinfertility? SUMMARY ANSWER: High-throughput screening (HTS) is a viable approach to much-needed drug discovery for male factor infertility. WHAT IS KNOWN ALREADY: There is both huge demand and a genuine clinical need for new treatment options for infertile men. However, the time, effort and resources required for drug discovery are currently exorbitant, due to the unique challenges of the cellular, physical and functional properties of human spermatozoa and a lack of appropriate assay platform. STUDY DESIGN, SIZE, DURATION: Spermatozoa were obtained from healthy volunteer research donors and subfertile patients undergoing IVF/ICSI at a hospital-assisted reproductive techniques clinic between January 2012 and November 2016. PARTICIPANTS/MATERIALS, SETTING, METHODS: A HTS assay was developed and validated using intracellular calcium ([Ca2+]i) as a surrogate for motility in human spermatozoa. Calcium fluorescence was detected using a Flexstation microplate reader (384-well platform) and compared with responses evoked by progesterone, a compound known to modify a number of biologically relevant behaviours in human spermatozoa. Hit compounds identified following single point drug screen (10 μM) of an ion channel-focussed library assembled by the University of Dundee Drug Discovery Unit were rescreened to ensure potency using standard 10 point half-logarithm concentration curves, and tested for purity and integrity using liquid chromatography and mass spectrometry. Hit compounds were grouped by structure activity relationships and five representative compounds then further investigated for direct effects on spermatozoa, using computer-assisted sperm assessment, sperm penetration assay and whole-cell patch clamping. MAIN RESULTS AND THE ROLE OF CHANCE: Of the 3242 ion channel library ligands screened, 384 compounds (11.8%) elicited a statistically significant increase in calcium fluorescence, with greater than 3× median absolute deviation above the baseline. Seventy-four compounds eliciting ≥50% increase in fluorescence in the primary screen were rescreened and evaluated further, resulting in 48 hit compounds that produced a concentration-dependent increase in [Ca2+]i. Sperm penetration studies confirmed in vitro exposure to two hit compounds (A and B) resulted in significant improvement in functional motility in spermatozoa from healthy volunteer donors (A: 1 cm penetration index 2.54, 2 cm penetration index 2.49; P < 0.005 and B: 1 cm penetration index 2.1, 2 cm penetration index 2.6; P < 0.005), but crucially, also in patient samples from those undergoing fertility treatment (A: 1 cm penetration index 2.4; P = 0.009, 2 cm penetration index 3.6; P = 0.02 and B: 1 cm penetration index 2.2; P = 0.0004, 2 cm penetration index 3.6; P = 0.002). This was primarily as a result of direct or indirect CatSper channel action, supported by evidence from electrophysiology studies of individual sperm. LIMITATIONS, REASONS FOR CAUTION: Increase and fluxes in [Ca2+]i are fundamental to the regulation of sperm motility and function, including acrosome reaction. The use of calcium signalling as a surrogate for sperm motility is acknowledged as a potential limitation in this study

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Martins da Silva SJ, Brown SG, Sutton K, King LV, Ruso H, Gray DW et al. Drug discovery for male subfertility using high-throughput screening: a new approach to an unsolved problem. Human Reproduction. 2017 Mar 16;32(5):974-984. Available from, DOI: 10.1093/humrep/dex055