Publications by authors named "Jochen Buck"

Article Synopsis
  • * His research demonstrated that cAMP is crucial for sperm movement, which is necessary for fertilization.
  • * Current studies are exploring agents that inhibit cAMP production to develop new nonhormonal contraceptives, potentially transforming methods of birth control.
View Article and Find Full Text PDF

Because nearly half of pregnancies worldwide are unintended, available contraceptive methods are inadequate. Moreover, due to the striking imbalance between contraceptive options available for men compared to the myriad of options available to women, there is an urgent need for new methods of contraception for men. This review summarizes ongoing efforts to develop male contraceptives highlighting the unique aspects particular to on-demand male contraception, where a man takes a contraceptive only when and as often as needed.

View Article and Find Full Text PDF

Mammalian sperm must undergo capacitation to become fertilization-competent. While working on mice, we recently developed a new methodology for treating sperm which results in higher rates of fertilization and embryo development after fertilization. Sperm incubated in media devoid of nutrients lose motility, although they remain viable.

View Article and Find Full Text PDF

Mammalian sperm require sufficient energy to support motility and capacitation for successful fertilization. Previous studies cataloging the changes to metabolism in sperm explored ejaculated human sperm or dormant mouse sperm surgically extracted from the cauda epididymis. Due to the differences in methods of collection, it remains unclear whether any observed differences between mouse and human sperm represent species differences or reflect the distinct maturation states of the sperm under study.

View Article and Find Full Text PDF

Dinoflagellates of the family Kryptoperidiniaceae, known as "dinotoms", possess diatom-derived endosymbionts and contain individuals at three successive evolutionary stages: a transiently maintained kleptoplastic stage; a stage containing multiple permanently maintained diatom endosymbionts; and a further permanent stage containing a single diatom endosymbiont. Kleptoplastic dinotoms were discovered only recently, in Durinskia capensis; until now it has not been investigated kleptoplastic behavior and the metabolic and genetic integration of host and prey. Here, we show D.

View Article and Find Full Text PDF

Male mice lacking the androgen receptor (AR) in pancreatic β cells exhibit blunted glucose-stimulated insulin secretion (GSIS), leading to hyperglycemia. Testosterone activates an extranuclear AR in β cells to amplify glucagon-like peptide-1 (GLP-1) insulinotropic action. Here, we examined the architecture of AR targets that regulate GLP-1 insulinotropic action in male β cells.

View Article and Find Full Text PDF

Targeted disruption of the soluble adenylyl cyclase (ADCY10; sAC) gene results in male-specific sterility without affecting spermatogenesis, mating behavior, or spermatozoa morphology and count; however, it dramatically impairs sperm motility and prevents capacitation. These phenotypes were identified in sperm from sAC null mice surgically extracted from the epididymis and studied . Epididymal sperm are dormant, and never exposed to physiological activators in semen or the female reproductive tract.

View Article and Find Full Text PDF

We investigated whether a clinically used carbonic anhydrase inhibitor (CAIs) can modulate intraocular pressure (IOP) through soluble adenylyl cyclase (sAC) signaling. IOP was measured 1 h after topical treatment with brinzolamide, a topically applied and clinically used CAIs, using direct cannulation of the anterior chamber in sAC knockout (KO) mice or C57BL/6J mice in the presence or absence of the sAC inhibitor (TDI-10229). Mice treated with the sAC inhibitor TDI-10229 had elevated IOP.

View Article and Find Full Text PDF

Free energy perturbation is a computational technique that can be used to predict how small changes to an inhibitor structure will affect the binding free energy to its target. In this paper, we describe the utility of free energy perturbation with FEP+ in the hit-to-lead stage of a drug discovery project targeting soluble adenyl cyclase. The project was structurally enabled by X-ray crystallography throughout.

View Article and Find Full Text PDF

Nearly half of all pregnancies are unintended; thus, existing family planning options are inadequate. For men, the only choices are condoms and vasectomy, and most current efforts to develop new contraceptives for men impact sperm development, meaning that contraception requires months of continuous pretreatment. Here, we provide proof-of-concept for an innovative strategy for on-demand contraception, where a man would take a birth control pill shortly before sex, only as needed.

View Article and Find Full Text PDF

Soluble adenylyl cyclase (sAC: ADCY10) is an enzyme involved in intracellular signaling. Inhibition of sAC has potential therapeutic utility in a number of areas. For example, sAC is integral to successful male fertility: sAC activation is required for sperm motility and ability to undergo the acrosome reaction, two processes central to oocyte fertilization.

View Article and Find Full Text PDF

In mammalian cells, 10 different adenylyl cyclases produce the ubiquitous second messenger, cyclic adenosine monophosphate (cAMP). Amongst these cAMP-generating enzymes, bicarbonate (HCO )-regulated soluble adenylyl cyclase (sAC; ADCY10) is uniquely essential in sperm for reproduction. For this reason, sAC has been proposed as a potential therapeutic target for non-hormonal contraceptives for men.

View Article and Find Full Text PDF

In humans, the prototypical second messenger cyclic AMP is produced by 10 adenylyl cyclase isoforms, which are divided into two classes. Nine isoforms are G protein coupled transmembrane adenylyl cyclases (tmACs; ADCY1-9) and the 10th is the bicarbonate regulated soluble adenylyl cyclase (sAC; ADCY10). This review details why sAC is uniquely druggable and outlines ways to target sAC for novel forms of male and female contraception.

View Article and Find Full Text PDF
Article Synopsis
  • * Diatoms use Lhcx proteins, especially Lhcx2, for energy-dependent fluorescence quenching (qE), which helps them manage excess light energy during iron limitation.
  • * Our study shows that Lhcx2 expression rapidly increases under iron stress, enhancing qE and leading to various changes in chlorophyll content, photosystems, and the management of reactive oxygen species in diatoms.
View Article and Find Full Text PDF

Photosynthetic organisms in nature often experience light fluctuations. While low light conditions limit the energy uptake by algae, light absorption exceeding the maximal rate of photosynthesis may go along with enhanced formation of potentially toxic reactive oxygen species. To preempt high light-induced photodamage, photosynthetic organisms evolved numerous photoprotective mechanisms.

View Article and Find Full Text PDF
Article Synopsis
  • Soluble adenylyl cyclase (sAC) is crucial for male fertility, as confirmed by genetic studies in both mice and humans.
  • Ex vivo studies reveal that sAC is necessary for sperm capacitation and motility in mouse sperm, while the activity in human sperm is already activated post-ejaculation.
  • The findings suggest that inhibiting sAC can prevent key processes in both mouse and human sperm, highlighting its potential for use in non-hormonal contraceptives delivered via intravaginal devices.
View Article and Find Full Text PDF

Soluble adenylyl cyclase (sAC) has gained attention as a potential therapeutic target given the role of this enzyme in intracellular signaling. We describe successful efforts to design improved sAC inhibitors amenable for interrogation of sAC inhibition to assess its potential therapeutic applications. This work culminated in the identification of TDI-10229 (), which displays nanomolar inhibition of sAC in both biochemical and cellular assays and exhibits mouse pharmacokinetic properties sufficient to warrant its use as an tool compound.

View Article and Find Full Text PDF

Soluble adenylyl cyclase (sAC; ADCY10) is a bicarbonate (HCO )-regulated enzyme responsible for the generation of cyclic adenosine monophosphate (cAMP). sAC is distributed throughout the cell and within organelles and, as such, plays a role in numerous cellular signalling pathways. Carbonic anhydrases (CAs) nearly instantaneously equilibrate HCO , protons and carbon dioxide (CO); because of the ubiquitous presence of CAs within cells, HCO -regulated sAC can respond to changes in any of these factors.

View Article and Find Full Text PDF

The evolutionarily conserved soluble adenylyl cyclase (sAC, ADCY10) mediates cAMP signaling exclusively in intracellular compartments. Because sAC activity is sensitive to local concentrations of ATP, bicarbonate, and free Ca, sAC is potentially an important metabolic sensor. Nonetheless, little is known about how sAC regulates energy metabolism in intact cells.

View Article and Find Full Text PDF

Mammalian sperm acquire fertilization capacity in the female reproductive tract in a process known as capacitation. During capacitation, sperm change their motility pattern (i.e.

View Article and Find Full Text PDF

Mammalian sperm are stored in the epididymis in a dormant state. Upon ejaculation, they must immediately start producing sufficient energy to maintain motility and support capacitation. While this increased energy demand during capacitation is well established, it remains unclear how mouse sperm modify their metabolism to meet this need.

View Article and Find Full Text PDF

Efforts to develop new male or female nonhormonal, orally available contraceptives assume that to be effective and safe, targets must be (1) essential for fertility; (2) amenable to targeting by small-molecule inhibitors; and (3) restricted to the germline. In this perspective, we question the third assumption and propose that despite its wide expression, soluble adenylyl cyclase (sAC: ADCY10), which is essential for male fertility, is a valid target. We hypothesize that an acute-acting sAC inhibitor may provide orally available, on-demand, nonhormonal contraception for men without adverse, mechanism-based effects.

View Article and Find Full Text PDF

Incomplete understanding of how hepatosteatosis transitions to fibrotic non-alcoholic steatohepatitis (NASH) has limited therapeutic options. Two molecules that are elevated in hepatocytes in human NASH liver are cholesterol, whose mechanistic link to NASH remains incompletely understood, and TAZ, a transcriptional regulator that promotes fibrosis but whose mechanism of increase in NASH is unknown. We now show that increased hepatocyte cholesterol upregulates TAZ and promotes fibrotic NASH.

View Article and Find Full Text PDF