Expanding the pipeline for multipurpose prevention technologies: compounds with potential activity to prevent or treat HIV and other STIs.

BACKGROUND: Continued high incidence of HIV and other STIs, paired with rising antibiotic resistance to a number of existing treatments, warrants the development of new pharmaceutical approaches for STI prevention. Multipurpose prevention technologies (MPTs) offer an innovative approach for expanding HIV/STI prevention. The majority of MPT product candidates currently in development include HIV prevention, while only half include compounds active against non-HIV STIs. METHODS: This narrative review focuses on compounds in preclinical development (in vitro and in vivo) through phase 3 clinical trials with activity against one or more of the following infections: HIV, HSV-1, HSV-2, Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, and Trichomonas vaginalis. Bacterial vaginosis is included due to its association with increased risk of STIs. The focus is on compounds with novel mechanisms of action and prophylactic and/or therapeutic potential. Articles published in PubMed between 2011 and 2021, NIH RePorter and conference abstracts and proceedings between 2020 and 2021 were searched. Excluded from the review are compounds that are already being used in MPT product candidates. MAIN RESULTS: There is a growing pipeline of compounds targeting viral STIs, many of which have successfully transitioned from preclinical to clinical stages of development. However, the product development pipeline remains limited for compounds that target bacterial STIs. CONCLUSIONS: The paucity of new pharmaceutical approaches for STI prevention, particularly non-HIV STIs, remains a public health gap. Future funding priorities should include STI prevention research. Despite limited attention to STI prevention in the development of MPTs, many research institutions worldwide are working on discoveries of new compounds, exploring new indications for existing drugs or on innovative drug delivery mechanisms. Our findings can be used to connect researchers across the globe to advance the development of compounds that have potential as active pharmaceutical ingredients in future MPTs.

A low-molecular-weight antagonist for the human thyrotropin receptor with therapeutic potential for hyperthyroidism.

Low-molecular-weight (LMW) antagonists for TSH receptor (TSHR) may have therapeutic potential as orally active drugs to block stimulating antibodies (TsAbs) in Graves' hyperthyroidism. We describe an approach to identify LMW ligands for TSHR based on Org41841, a LMW partial agonist for the LH/choriogonadotropin receptor and TSHR. We used molecular modeling and functional experiments to guide the chemical modification of Org41841. We identified an antagonist (NIDDK/CEB-52) that selectively inhibits activation of TSHR by both TSH and TsAbs. Whereas initially characterized in cultured cells overexpressing TSHRs, the antagonist was also active under more physiologically relevant conditions in primary cultures of human thyrocytes expressing endogenous TSHRs in which it inhibited TSH- and TsAb-induced up-regulation of mRNA transcripts for thyroperoxidase. Our results establish this LMW compound as a lead for the development of higher potency antagonists and serve as proof of principle that LMW ligands that target TSHR could serve as drugs in patients with Graves' disease.

Synthesis of Substituted 2-phenylhistamines via a Microwave Promoted Suzuki Coupling.

Substitutions on the 2-position of the imidizole ring of histamine have proven useful in a number of biochemical settings. Current art for the synthesis of these constructs relies upon a cumbersome and low-yielding condensation reaction. Here-in we report a new procedure for the synthesis of a series of substituted 2-phenylhistamines utilizing a microwave-promoted Suzuki coupling.

Evaluation of small-molecule modulators of the luteinizing hormone/choriogonadotropin and thyroid stimulating hormone receptors: structure-activity relationships and selective binding patterns.

The substituted thieno[2,3-d]pyrimidine 3 (Org 41841), a partial agonist for the luteinizing hormone/choriogonadotropin receptor (LHCGR) and the closely related thyroid-stimulating hormone receptor (TSHR), was fundamentally altered, and the resulting analogues were analyzed for their potencies, efficacies, and specificities at LHCGR and TSHR. Chemical modification of the parent compound combined with prior mutagenesis of TSHR provided compelling experimental evidence in support of computational models of 3 binding to TSHR and LHCGR within their transmembrane cores. Biochemical analysis of a specific modification to the chemical structure of 3 provides additional evidence of a H-bond between the ligand and a glutamate residue in transmembrane helix 3, which is conserved in both receptors. Several key interactions were surveyed to determine their respective biochemical roles in terms of both van der Waals dimensions and hydrogen bond capacity and the respective relationship to biological activity.

A low molecular weight agonist signals by binding to the transmembrane domain of thyroid-stimulating hormone receptor (TSHR) and luteinizing hormone/chorionic gonadotropin receptor (LHCGR).

Many cognate low molecular weight (LMW) agonists bind to seven transmembrane-spanning receptors within their transmembrane helices (TMHs). The thienopyrimidine org41841 was identified previously as an agonist for the luteinizing hormone/chorionic gonadotropin receptor (LHCGR) and suggested to bind within its TMHs because it did not compete for LH binding to the LHCGR ectodomain. Because of its high homology with LHCGR, we predicted that thyroid-stimulating hormone receptor (TSHR) might be activated by org41841 also. We show that org41841 is a partial agonist for TSHR but with lower potency than for LHCGR. Analysis of three-dimensional molecular models of TSHR and LHCGR predicted a binding pocket for org41841 in common clefts between TMHs 3, 4, 5, 6, and 7 and extracellular loop 2 in both receptors. Evidence for this binding pocket was obtained in signaling studies with chimeric receptors that exhibited improved responses to org41841. Furthermore, a key receptor-ligand interaction between the highly conserved negatively charged E3.37 and the amino group of org41841 predicted by docking of the ligand into the three-dimensional TSHR model was experimentally confirmed. These findings provide the first evidence that, in contrast to the ectodomain binding of cognate ligands, a LMW agonist can bind to and activate glycoprotein hormone receptors via interaction with their transmembrane domain.