Using (hetero)aryl fluorosulfonates as versatile electrophiles, facile on‐DNA cross‐coupling reactions of Suzuki, Sonogashira, and Buchwald are reported here. Notably, all of these reactions show excellent functional group tolerance, mild reaction conditions (relative low temperature and open to air), rich heterocyclic coupling partners, and more importantly, DNA‐compatibility. Thus, these new reactions based on efficient formation of C(sp²)‐C(sp²), C(sp²)‐C(sp), and C(sp²)‐N bonds are highly amenable to synthesis of DNA‐encoded libraries with great molecular diversity.

Significance: Unfortunately, the need for ideal medical treatment of acute ischemic stroke is still largely unmet. One of the contributing factors to the deleterious neuronal death is the opening of acid-sensing ion channels (ASICs) at reduced pH, which in turn, activates other calcium-permeable channels that initiate the catastrophic cascade. Here, we report the discovery of an antibody that blocks the ASIC1a with high specificity and potency. Infusion of this antibody reduces the damaged area from brain ischemia in the murine stroke model. We hypothesize that using antibodies to target ASIC1a is a valid approach for future stroke therapy. The antibody that we report here has the potential to be further developed as drug candidate.

Although insulin is a life-saving medicine, administration by daily injection remains problematic. Our goal was to exploit the power of DNA-encoded libraries to identify molecules with insulin-like activity but with the potential to be developed as oral drugs. Our strategy involved using a 10⁴-member DNA-encoded library containing 160 Traditional Chinese Medicines (nDEL) to identify molecules that bind to and activate the insulin receptor. Importantly, we used the natural ligand, insulin, to liberate bound molecules. Using this selection method on our relatively small, but highly diverse, nDEL yielded a molecule capable of both binding to and activating the insulin receptor. Chemical analysis showed this molecule to be a polycyclic analog of the guanidine metformin, a known drug used to treat diabetes. By using our protocol with other, even larger, DELs we can expect to identify additional organic molecules capable of binding to and activating the insulin receptor.

Tumor necrosis factor α (TNF‐α) inhibitors have shown great success in the treatment of autoimmune diseases. However, to date, approved drugs targeting TNF‐α are restricted to biological macromolecules, largely due to the difficulties in using small molecules for pharmaceutical intervention of protein–protein interactions. Herein the power of a natural product‐enriched DNA‐encoded library (nDEL) is exploited to identify small molecules that interfere with the protein–protein interaction between TNF‐α and the cognate receptor. Initially, to select molecules capable of binding to TNF‐α , “late‐stage” DNA modification method is applied to construct an nDEL library consisted of 400 sterically diverse natural products and pharmaceutically active chemicals. Several natural products, including kaempferol, identified not only show direct interaction with TNF‐α, but also lead to the blockage of TNF‐α/TNFR1 interaction. Significantly, kaempferol attenuates the TNF‐α signaling in cells and reduces the 12‐O‐tetradecanoylphorbol‐13‐acetateinduced ear inflammation in mice. Structure‐activity‐relationship analyses demonstrate the importance of substitution groups at C‐3, C‐7, and C‐4' of kaempferol. The nDEL hit, kaempferol, represents a novel chemical scaffold capable of specifically recognizing TNF‐α and blocking its signal transduction, a promising starting point for the development of a small molecule TNF‐α inhibitor for use in the clinical setting.

Numerous currently incurable human diseases have been causally linked to mutations in connexin (Cx) genes. In several instances, pathological mutations generate abnormally active Cx hemichannels, referred to also as "leaky" hemichannels. The goal of this study was to assay the in vivo efficacy of a potent antagonist antibody targeting Cx hemichannels. We employed the antibody to treat Cx30^A88V/A88V adult mutant mice, the only available animal model of Clouston syndrome, a rare orphan disease caused by Cx30 p.A88V leaky hemichannels. To gain mechanistic insight into antibody action, we also performed patch clamp recordings, Ca²⁺ imaging and ATP release assay in vitro. Two weeks of antibody treatment sufficed to repress cell hyperproliferation in skin and reduce hypertrophic sebaceous glands (SGs) to wild type (wt) levels. These effects were obtained whether mutant mice were treated topically, by application of an antibody cream formulation, or systemically, by intraperitoneal antibody injection. Experiments with mouse primary keratinocytes and HaCaT cells revealed the antibody blocked Ca²⁺ influx and diminished ATP release through leaky Cx30 p.A88V hemichannels. Our results show anti-Cx antibody treatment was effective in vivo and sufficient to counteract the effects of pathological connexin expression in Cx30^A88V/A88V mice. In vitro experiments suggest antibodies gained control over leaky hemichannels and contributed to restoring epidermal homeostasis. Therefore, regulating cell physiology by antibodies targeting the extracellular domain of Cxs may enforce an entirely new therapeutic strategy. These findings support the further development of antibodies as drugs to address unmet medical needs for Cx-related diseases. FUND: Fondazione Telethon, GGP19148; University of Padova, SID/BIRD187130; Consiglio Nazionale delle Ricerche, DSB.AD008.370.003\TERABIO-IBCN; National Science Foundation of China, 31770776; Science and Technology Commission of Shanghai Municipality, 16DZ1910200.