Discovery and Optimization of Selective Brain-Penetrant EBP Inhibitors that Enhance Oligodendrocyte Formation

The inhibition of emopamil binding protein (EBP), a sterol isomerase within the cholesterol biosynthesis pathway, promotes oligodendrocyte formation, which has been proposed as a potential therapeutic approach for treating multiple sclerosis. Herein, we describe the discovery and optimization of brain-penetrant, orally bioavailable inhibitors of EBP. A structure-based drug design approach from literature compound 1 led to the discovery of a hydantoin-based scaffold, which provided balanced physicochemical properties and potency and an improved in vitro safety profile. The long half-lives of early hydantoin-based EBP inhibitors in rodents prompted an unconventional optimization strategy, focused on increasing metabolic turnover while maintaining potency and a brain-penetrant profile. The resulting EBP inhibitor 11 demonstrated strong in vivo target engagement in the brain, as illustrated by the accumulation of EBP substrate zymostenol after repeated dosing. Furthermore, compound 11 enhanced the formation of oligodendrocytes in human cortical organoids, providing additional support for our therapeutic hypothesis.

Discovery of GDC-0077 (Inavolisib), a Highly Selective Inhibitor and Degrader of Mutant PI3Kα

Small molecule inhibitors that target the phosphatidylinositol 3-kinase (PI3K) signaling pathway have received significant interest for the treatment of cancers. The class I isoform PI3Kα is most commonly associated with solid tumors via gene amplification or activating mutations. However, inhibitors demonstrating both PI3K isoform and mutant specificity have remained elusive. Herein, we describe the optimization and characterization of a series of benzoxazepin-oxazolidinone ATP-competitive inhibitors of PI3Kα which also induce the selective degradation of the mutant p110α protein, the catalytic subunit of PI3Kα. Structure-based design informed isoform-specific interactions within the binding site, leading to potent inhibitors with greater than 300-fold selectivity over the other Class I PI3K isoforms. Further optimization of pharmacokinetic properties led to excellent in vivo exposure and efficacy and the identification of clinical candidate GDC-0077 (inavolisib, 32), which is now under evaluation in a Phase III clinical trial as a treatment for patients with PIK3CA-mutant breast cancer.

Identification of BRaf-Sparing Amino-Thienopyrimidines with Potent IRE1α Inhibitory Activity

Amino-quinazoline BRaf kinase inhibitor 2 was identified from a library screen as a modest inhibitor of the unfolded protein response (UPR) regulating potential anticancer target IRE1α. A combination of crystallographic and conformational considerations were used to guide structure-based attenuation of BRaf activity and optimization of IRE1α potency. Quinazoline 6-position modifications were found to provide up to 100-fold improvement in IRE1α cellular potency but were ineffective at reducing BRaf activity. A salt bridge contact with Glu651 in IRE1α was then targeted to build in selectivity over BRaf which instead possesses a histidine in this position (His539). Torsional angle analysis revealed that the quinazoline hinge binder core was ill-suited to accommodate the required conformation to effectively reach Glu651, prompting a change to the thienopyrimidine hinge binder. Resulting analogues such as 25 demonstrated good IRE1α cellular potency and imparted more than 1000-fold decrease in BRaf activity.

Optimization of globomycin analogs as novel gram-negative antibiotics

Discovery of novel classes of Gram-negative antibiotics with activity against multi-drug resistant infections is a critical unmet need. As an essential member of the lipoprotein biosynthetic pathway, lipoprotein signal peptidase II (LspA) is an attractive target for antibacterial drug discovery, with the natural product inhibitor globomycin offering a modestly-active starting point. Informed by structure-based design, the globomycin depsipeptide was optimized to improve activity against E. coli. Backbone modifications, together with adjustment of physicochemical properties, afforded potent compounds with good in vivo pharmacokinetic profiles. Optimized compounds such as 51 (E. coli MIC 3.1 μM) and 61 (E. coli MIC 0.78 μM) demonstrate broad spectrum activity against gram-negative pathogens and may provide opportunities for future antibiotic discovery.

Synthesis of Fused Imidazole-Containing Ring Systems via Dual Oxidative Amination of C(sp(3))-H Bonds

A general and efficient method for a metal-free one-pot synthesis of highly substituted fused imidazole-containing 5,5- and 5,6-fused bicyclic heterocycles is described. Starting from commercially available substrates and reagents, the reaction proceeds through two C-N bond formations and an oxidative dehydrogenation to form highly substituted products in good to excellent yield.

Palladium-catalyzed allylic C-H fluorination

The first catalytic allylic C-H fluorination reaction using a nucleophilic fluoride source is reported. Under the influence of a Pd/Cr cocatalyst system, simple olefin substrates undergo fluorination with Et3N·3HF in good yields with high branched:linear regioselectivity. The mild conditions and broad scope make this reaction a powerful alternative to established methods for the preparation of allylic fluorides from prefunctionalized substrates.

A highly stereoselective, modular route to (E)-vinylsulfones and to (Z)- and (E)-alkenes

A recently discovered radical fragmentation of 2-fluoro-6-pyridinoxy derivatives allows a new highly stereoselective and convergent route to (E)-vinylsulfones from allylic alcohols. Reductive desulfonylation or nickel-catalyzed couplings furnish di- and trisubstituted (E)- and (Z)-alkenes.

Highly demanding cross-metathesis in the synthesis of the C16-C30 fragment of dolabelide C

A highly demanding cross-metathesis (CM) reaction for the formation of the C24-C25 trisubstituted olefin of dolabelide C has been optimized. A difference in reactivity between the E and Z enone isomers in this reaction was uncovered, and the selection of the Z isomer of the starting enone was critical for the success of the cross-metathesis. Application to the synthesis of the C16-C30 fragment of dolabelide C is reported.

Neuauftreten und/oder Zunahme von Rheumaknoten unter Leflunomidtherapie bei RA-Patienten

This is the first description of the development of rheumatoid nodules in 3 rheumatoid arthritis patients following leflunomide therapy. The nodules were localized at typical sites with preference of the extensor side of hands and elbow. One nodule examined histologically revealed the typical architecture of RA nodules. In all 3 patients the time of onset of nodulosis was about 6 months after initiating the leflunomide therapy. In all 3 patients leflunomide was clinically efficacious concerning RA: remission or near remission was achieved. Due to the extent of nodulosis, the leflunomide therapy had to be stopped in 2 patients. Progression and acceleration of nodulosis is well known following MTX therapy in RA patients. It is caused by adenosine A1 receptor promotion of multinucleated giant cell formation by human monocytes. Leflunomide has no known influence on adenosine metabolism, so different pathogenetic mechanisms must be assumed for the induction of nodulosis by leflunomide.

[Listeria arthritis in chronic polyarthritis during low dose prednisolone and methotrexate therapy. Case report and review of the literature]

We report about a patient with polyarticular rheumatoid arthritis taking methotrexat and 5 mg prednisolone who developed in the course of a RA flare a septic arthritis in the right shoulder. Listeria monocytogenes could be identified as the causative bacteria. Clinically, the Listeria-induced septic arthritis could not be differentiated from rheumatoid arthritis; fever was not present. The synovial analysis showed a granulocytic effusion with 19,000 cells/ml; there was no microbiological growth within the first 24 hours. Only the low glucose level indicated a possible septic arthritis. After 48 hours, gram-positive bacterial growth was evident and Listeria monocytogenes could be isolated after 72 hours. Therapy was initiated by antibiotic treatment and arthrotomy with synovectomy followed by extensive irrigation which proved effective in bacterial elimination but joint destruction resulted. During the whole course, Listeria antibodies were negative and proved to be too insensitive. The incidence of Listeria-induced arthritis is very low; a review of the literature revealed only 24 reported cases. It occurs primarily in patients with rheumatic diseases under immunosuppression and in prosthetic joints. The diagnosis is based on cultural detection. It is important to cultivate synovial effusions for longer than 24 hours in order to identify Listeria. This is of relevance since Listeria serology is not sensitive.

Monoclonal antibody WGM1 directed against proteinase 3: an immunohistochemical marker for naphthol ASD chloroacetate

Enzyme histochemistry for naphthol ASD chloroacetate (NASDCA, 'Leder's stain') is used to identify the granulocyte lineage ranging from promyelocytes to mature neutrophils and is an additional tool for the characterization of leukemias. We demonstrated for the first time that NASDCA activity can be detected by routine immunohistochemistry and immunocytochemistry using the monoclonal antibody WGM1 directed against proteinase 3 (PR3; synonyms: Wegener's autoantigen, myeloblastin). Immunohisto- and immunocytochemical staining with WGM1 against PR3 and enzyme histochemistry for NASDCA produced identical staining patterns in normal myelomonocytic cells and cells of myeloid leukemia. This was additionally proven by double immunostainings. We have also shown that PR3 is one of the specific proteinases responsible for hydrolysis of NASDCA.

Incidence, target antigens, and clinical implications of antineutrophil cytoplasmic antibodies in rheumatoid arthritis

OBJECTIVE

To determine the incidence of antineutrophil cytoplasmic antibodies (ANCA) in rheumatoid arthritis (RA), to detect the target antigens of ANCA, and to compare clinical and laboratory data of ANCA+ with ANCA- patients with RA.

METHODS

385 sera of patients with RA were screened for ANCA by indirect immunofluorescence. ANCA+ sera were further analyzed for target antigens by ELISA: The ANCA+ patients were compared to randomly selected ANCA- patients with RA with respect to serological and radiological variables and extraarticular involvement.

RESULTS

ANCA were found in 16% of patients with RA (61/385 sera). All sera showed a perinuclear (pANCA) pattern. Antibodies directed against proteinase 3 were not observed. The analysis of ANCA+ and ANCA- patients revealed that the pANCA+ group exhibited significantly higher serological markers of inflammation (p < 0.005) and a higher incidence of rheumatoid factor (p < 0.005). Furthermore, vasculitic involvement was found at a higher frequency (p < 0.05) in the pANCA+ group. Five patients in the pANCA+ group had pulmonary involvement, but none in the pANCA- group.

CONCLUSION

pANCA in RA may be a marker for a more aggressive course of disease in respect to serological variables and extraarticular manifestations including rheumatoid vasculitis and lung involvement.

Proteinase 3, the target antigen of anticytoplasmic antibodies circulating in Wegener's granulomatosis. Immunolocalization in normal and pathologic tissues

Proteinase 3 was identified as the target antigen of anticytoplasmic antibodies (ACPA/c-ANCA) in Wegener's granulomatosis (WG). Using the murine monoclonal antibody (MAb) WGM2, the authors localized proteinase 3 on normal and pathologic tissue and in various human cell lines. Proteinase 3 was found in all granulocytes, mast cells, and a subset of monocytes (2-10% of peripheral blood monocytes). No crossreactivity of the MAb with other cells or tissue components was observed. Comparing various vasculitic and granulomatous tissues, WG granulomas contained more granulocytes. In tissue of WG, no crossreactivity of the MAb with tissue components such as blood vessel wall or endothelium was seen. The monocytic line THP-1 and the promyelocytic line HL 60 contained proteinase 3. Since proteinase 3 was only found in neutrophil granulocytes, mast cells, and a subset of monocytes, the presented data provide further evidence that granulocytes play a central role in the pathogenesis of WG.

Morphological differentiation of human lymphocyte subpopulations following polyclonal stimulation with bacteria and lectin

Mononuclear cells (MNC) were stimulated with different heat-treated gram-positive and -negative bacteria, and the lymphocyte subpopulation interaction, the proliferative response, and the immunoglobulin secretion were analyzed. It can be demonstrated that beta haemolytic streptococci and Staphylococcus aureus have a similar stimulation pattern: early stimulation of helper T cells, cell contacts of helper T cells and B cells, maximum proliferation on day 5 and 7, and Ig secretion peak on day 7. Klebsiella pneumoniae and Yersinia enterocolitica do not cause proliferation, while Ig secretion is seen on day 5. No cell contacts and no T cell stimulation are seen in the Klebsiella culture, whilst Yersinia causes slight helper T cell activation. In contrast, PHA induces strong T cell stimulation, proliferation and expansion of the suppressor T cell subpopulation. Leu 7-positive lymphocytes are not activated by any of these stimulants.