Tracy Jenkins

Antagonism of chemokine receptor CCR8 is ineffective in a primate model of asthma

Background Expression of the T-cell-associated chemokine receptor CCR8 and its ligand CCL1 have been demonstrated to be elevated in patients with asthma. CCR8 deficiency or inhibition in models of allergic airway disease in mice resulted in conflicting data. Objective To investigate the effects of a selective small molecule CCR8 inhibitor (ML604086) in a primate model of asthma. Methods ML604086 and vehicle were administered by intravenous infusion to 12 cynomolgus monkeys during airway challenge with Ascaris suum. Samples were collected throughout the study to measure pharmacokinetics (PK) and systemic CCR8 inhibition, as well as inflammation, T helper 2 (Th2) cytokines and mucus in bronchoalveolar lavage (BAL). Airway resistance and compliance were measured before and after allergen challenge, and in response to increasing concentrations of methacholine. Results ML604086 inhibited CCL1 binding to CCR8 on circulating T-cells>98% throughout the duration of the study. However, CCR8 inhibition had no significant effect on allergen-induced BAL eosinophilia and the induction of the Th2 cytokines IL-4, IL-5, IL-13 and mucus levels in BAL. Changes in airway resistance and compliance induced by allergen provocation and increasing concentrations of methacholine were also not affected by ML604086. Conclusions These results clearly demonstrate a dispensable role for CCR8 in ameliorating allergic airway disease in atopic primates, and suggest that strategies other than CCR8 antagonism should be considered for the treatment of asthma.

CDK12-mediated transcriptional regulation of noncanonical NF-κB components is essential for signaling

Combining a phenotypic screen with chemoproteomics reveals CDK12 as a potential therapeutic target to inhibit noncanonical NF-κB in inflammation and cancer. CDK12 promotes inflammation Activating mutations in components of the noncanonical nuclear factor κB (NF-κB) signaling pathway are implicated in various cancers, and ligands that stimulate this pathway are increased in abundance in autoimmune inflammation, which makes this pathway an attractive therapeutic target. By combining a phenotypic screen with chemoproteomics analysis, Henry et al. found a compound that inhibited noncanonical NF-κB signaling by targeting cyclin-dependent kinase 12 (CDK12). By phosphorylating RNA polymerase II, CDK12 enables expression of the kinase NIK, which is required to stimulate the noncanonical NF-κB pathway. Together, these data suggest that CDK12 inhibitors may have therapeutic value in cancer and inflammatory disease. Members of the family of nuclear factor κB (NF-κB) transcription factors are critical for multiple cellular processes, including regulating innate and adaptive immune responses, cell proliferation, and cell survival. Canonical NF-κB complexes are retained in the cytoplasm by the inhibitory protein IκBα, whereas noncanonical NF-κB complexes are retained by p100. Although activation of canonical NF-κB signaling through the IκBα kinase complex is well studied, few regulators of the NF-κB–inducing kinase (NIK)–dependent processing of noncanonical p100 to p52 and the subsequent nuclear translocation of p52 have been identified. We discovered a role for cyclin-dependent kinase 12 (CDK12) in transcriptionally regulating the noncanonical NF-κB pathway. High-content phenotypic screening identified the compound 919278 as a specific inhibitor of the lymphotoxin β receptor (LTβR), and tumor necrosis factor (TNF) receptor superfamily member 12A (FN14)–dependent nuclear translocation of p52, but not of the TNF-α receptor–mediated nuclear translocation of p65. Chemoproteomics identified CDK12 as the target of 919278. CDK12 inhibition by 919278, the CDK inhibitor THZ1, or siRNA-mediated knockdown resulted in similar global transcriptional changes and prevented the LTβR- and FN14-dependent expression of MAP3K14 (which encodes NIK) as well as NIK accumulation by reducing phosphorylation of the carboxyl-terminal domain of RNA polymerase II. By coupling a phenotypic screen with chemoproteomics, we identified a pathway for the activation of the noncanonical NF-κB pathway that could serve as a therapeutic target in autoimmunity and cancer.