Discovery of Potent Azetidine-Benzoxazole MerTK Inhibitors with In Vivo Target Engagement.

Inhibition of the receptor tyrosine kinase MerTK by small molecules has the potential to augment the immune response to tumors. Potent, selective inhibitors with high levels of in vivo target engagement are needed to fully evaluate the potential use of MerTK inhibitors as cancer therapeutics. We report the discovery and optimization of a series of pyrazinamide-based type 1.5 MerTK inhibitors bearing an azetidine-benzoxazole substituent. Compound 31 potently engages the target in vivo and demonstrates single agent activity in the immune-driven MC-38 murine syngeneic tumor model.

Nonclinical evaluations of deucravacitinib and Janus kinase inhibitors in homeostatic and inflammatory pathways.

Translational medicine provides insight into novel drugs and predicts unwanted effects. In well-characterized pathways (e.g., cytokine-Janus kinase [JAK]-signal transducers and activators of transcription [STAT]), a variety of in vitro assessments were used to estimate selectivity of effects on different potential targets (i.e., JAK1, JAK2, JAK3, and tyrosine kinase 2 [TYK2]). Several approved drugs were characterized as selective for the JAK family. These assessments are challenged by a lack of compounds that only inhibit one JAK family member. Deucravacitinib is a first-in-class, oral, selective, allosteric inhibitor of TYK2, a kinase required for IL-12, IL-23, and Type I interferon signaling. Unlike deucravacitinib, which selectively binds to the TYK2 regulatory domain, JAK1,2,3 inhibitors target the catalytic domain, contributing to nonselective targeting of JAK1,2,3. Cytokines associated with JAK1,2,3 signaling are required for both immune and nonimmune functions. A similar laboratory abnormality profile was observed in clinical trials using JAK1,2,3 inhibitors that has not been observed with deucravacitinib. In vitro testing of JAK1,2,3 inhibitors has relied upon assays of signal transduction, such as those measuring STAT phosphorylation, for estimates of potency and selectivity. These assay systems can be effective in estimating in vivo efficacy; however, they may not provide insight into downstream outcomes of receptor signaling, which may be more relevant for evaluating safety aspects. Assay systems assessing functional outcomes from cells may yield a more useful translational evaluation. Here, deucravacitinib was assessed for potency and selectivity versus three representatives of the JAK inhibitor class (tofacitinib, baricitinib, and upadacitinib) based on functional assays. JAK inhibitors had suppressive activity against JAK2-dependent hematopoietic colony-forming assays modeling thrombopoiesis, erythropoiesis, and myelopoiesis; however, deucravacitinib did not. Deucravacitinib had limited potency against NK cells, cytotoxic T cells, T-helper cells, and regulatory T cells activated by JAK1/JAK3-dependent common gamma chain cytokines. These data are consistent with the biologic role of JAK1,2,3 and pharmacodynamic changes in clinical laboratory abnormalities. Against TYK2-dependent cytokines, deucravacitinib selectively inhibited Type I interferon stimulation of monocytes and dendritic cells and was a more potent inhibitor than JAK inhibitors. IL-12 and IL-23 functional outputs were similarly potently inhibited by deucravacitinib. Results are consistent with deucravacitinib selectively inhibiting TYK2.

Anticancer Effects of BAF312 (Siponimod) in Epithelial Ovarian Cancer.

BACKGROUND/AIM: Epithelial ovarian cancer (EOC) is a lethal disease that is the fifth leading cause of cancer-related death in women. BAF312 (siponimod) is a potent and selective sphingosine-1-phosphate (S1P) receptor modulator that has been approved as a treatment for multiple sclerosis. In addition to its immunomodulatory action, BAF312 shows preclinical antitumor effects in several cancer types. This study sought to determine whether BAF312 had anticancer properties against EOC using in vitro and in vivo models. MATERIALS AND METHODS: EOC cell lines A2780, SKOV3ip1, A2780-CP20, and SKOV3-TR were treated with BAF312 and tested for cell proliferation, apoptosis, and migration using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, fluorescence-activated cell sorting, and migration assays. We investigated the expression of sphingosine-1-phosphate receptor 1 (S1PR1) in most EOC cell lines through western blot analysis. To investigate potential mechanisms, western blot analysis was used to assess the expression of AKT serine/threonine kinase 1 (AKT) and extracellular-regulated kinase (ERK) after BAF312 treatment. We also created poly(D,L-lactide-co-glycolide) nanoparticles encapsulating BAF312 (PLGA-NP-BAF312) for in vivo therapy. The average size and zeta potential of PLGA-NP-BAF312 were determined using dynamic light scattering. The therapeutic efficacy of PLGA-NP-BAF312 was tested in an A2780 tumor-bearing orthotopic mouse model of EOC. RESULTS: S1PR1 was overexpressed in most EOC cell lines. BAF312 significantly reduced cell proliferation and migration while inducing significant apoptosis in all EOC cell lines. PLGA-NP-BAF312 treatment significantly reduced tumor weights in A2780 tumor-bearing mice. Furthermore, the anticancer effects of BAF312 were associated with reduced phosphorylation of ERK and AKT. CONCLUSION: Our findings show that BAF312 has significant anticancer effects in EOC cells by inhibiting the ERK and AKT pathways, and might potentially be used to treat EOCs.

Class Effect Unveiled: PPARγ Agonists and MEK Inhibitors in Cancer Cell Differentiation.

Epithelial-to-mesenchymal transition (EMT) plays a major role in breast cancer progression and the development of drug resistance. We have previously demonstrated a trans-differentiation therapeutic approach targeting invasive dedifferentiated cancer cells. Using a combination of PPARγ agonists and MEK inhibitors, we forced the differentiation of disseminating breast cancer cells into post-mitotic adipocytes. Utilizing murine breast cancer cells, we demonstrated a broad class effect of PPARγ agonists and MEK inhibitors in inducing cancer cell trans-differentiation into adipocytes. Both Rosiglitazone and Pioglitazone effectively induced adipogenesis in cancer cells, marked by PPARγ and C/EBPα upregulation, cytoskeleton rearrangement, and lipid droplet accumulation. All tested MEK inhibitors promoted adipogenesis in the presence of TGFß, with Cobimetinib showing the most prominent effects. A metastasis ex vivo culture from a patient diagnosed with triple-negative breast cancer demonstrated a synergistic upregulation of PPARγ with the combination of Pioglitazone and Cobimetinib. Our results highlight the potential for new therapeutic strategies targeting cancer cell plasticity and the dedifferentiation phenotype in aggressive breast cancer subtypes. Combining differentiation treatments with standard therapeutic approaches may offer a strategy to overcome drug resistance.

JAK inhibitors inhibit angiogenesis by reducing VEGF production from rheumatoid arthritis-derived fibroblast-like synoviocytes.

INTRODUCTION/OBJECTIVES: JAK/STAT signaling inhibition exerts therapeutic effects on angiogenesis in rheumatoid arthritis (RA). However, whether the inhibitory effect differs among JAK inhibitors because of differing selectivity is unknown. Therefore, we compared the inhibitory effects of tofacitinib, baricitinib, peficitinib, upadacitinib, and filgotinib on angiogenesis. METHOD: RA-derived fibroblast-like synoviocytes (RA-FLS) were seeded on type I collagen gel, and human umbilical vein endothelial cells (HUVECs) were directly added. The control and aforementioned JAK inhibitors were added to the medium, followed by stimulation with interleukin (IL)-6 and soluble IL-6 receptor (sIL-6R). Each JAK inhibitor's concentration was determined based on estimated blood concentrations. The vascular endothelial growth factor (VEGF) concentration was evaluated with an enzyme-linked immunosorbent assay using the medium from the first exchange. A migration assay was performed, and HUVEC migration was evaluated using CD31 fluorescence immunostaining. RESULTS: Hematoxylin-eosin staining showed that compared with the non-JAKi treatment group, the JAKi treatment group markedly degenerated in the sub-lining and deep lining, with decreased lymphocyte infiltration and neovascularization [Rooney's score subscale, non-JAKi vs JAKi (median, 6.5 vs 2.5, p = 0.005)]. In vitro, IL-6 and sIL-6R administration increased VEGF production from RA-FLS and promoted neovascularization in HUVECs, and JAK-inhibitor administration, which decreased VEGF production from RA-FLS and suppressed HUVEC migration, inhibited neovascularization in RA-FLS and HUVEC co-cultures. CONCLUSIONS: The JAK inhibitors suppressed IL-6-induced angiogenesis via decreased VEGF production and HUVEC migration in RA-FLS and HUVEC co-cultures. No significant differences were observed among the JAK inhibitors, whose anti-angiogenic effect may be an important mechanism for RA treatment. Key Points • JAK inhibitors inhibit angiogenesis in RA by reducing VEGF production from RA-derived fibroblast-like synoviocytes. • Our study provides new insights into RA treatment by elucidating the anti-angiogenic effect of JAK inhibitors.

Effect of 28 days treatment of baricitinib on mechanical allodynia, osteopenia, and loss of nerve fibers in an experimental model of type-1 diabetes mellitus.

BACKGROUND: Type-1 diabetes mellitus (T1DM) is associated with numerous health problems, including peripheral neuropathy, osteoporosis, and bone denervation, all of which diminish quality of life. However, there are relatively few therapies to treat these T1DM-related complications. Recent studies have shown that Janus kinase (JAK) inhibitors reverse aging- and rheumatoid arthritis-induced bone loss and reduce pain associated with peripheral nerve injuries, and rheumatoid arthritis. Thus, we assessed whether a JAK1/JAK2 inhibitor, baricitinib, ameliorates mechanical pain sensitivity (a measure of peripheral neuropathy), osteoporosis, and bone denervation in the femur of mice with T1DM. METHODS: Female ICR mice (13 weeks old) received five daily administrations of streptozotocin (ip, 50 mg/kg) to induce T1DM. At thirty-one weeks of age, mice were treated with baricitinib (po; 40 mg/kg/bid; for 28 days) or vehicle. Mechanical sensitivity was evaluated at 30, 33, and 35 weeks of age on the plantar surface of the right hind paw. At the end of the treatment, mice were sacrificed, and lower extremities were harvested for microcomputed tomography and immunohistochemistry analyses. RESULTS: Mice with T1DM exhibited greater blood glucose levels, hind paw mechanical hypersensitivity, trabecular bone loss, and decreased density of calcitonin gene-related peptide-positive and tyrosine hydroxylase-positive axons within the marrow of the femoral neck compared to control mice. Baricitinib treatment significantly reduced mechanical hypersensitivity and ameliorated sensory and sympathetic denervation at the femoral neck, but it did not reverse trabecular bone loss. CONCLUSIONS: Our findings suggest that baricitinib may represent a new therapeutic alternative to treat T1DM-induced peripheral neuropathy and bone denervation.

Siponimod following Alemtuzumab in secondary progressive MS: investigating sequential therapy-A case series.

Alemtuzumab, a humanized anti-CD52 monoclonal antibody, is approved for treatment of highly active relapsing multiple sclerosis (MS) but requires vigilant post-treatment monitoring due to associated risks. The prescription of subsequent therapies following Alemtuzumab, as mandated by label guidance for a treatment-free period of at least 5 years, presents a complex challenge, particularly if there is concurrent conversion to secondary progressive disease course. We described a case-series of five patients starting therapy with Siponimod and followed up for 12 months period converted to secondary progressive MS previously exposed to Alemtuzumab. All patients received Siponimod 2 mg. Clinical evaluation measured with Expanded Disability Status Scale and cognitive evaluation measured with Brief International Cognitive Assessment for Multiple Sclerosis were stable after 12 months on therapy. No severe lymphopenia was recorded, nor serious adverse events. In conclusion, the long-term management of patients treated with Alemtuzumab transitioning to secondary progressive MS requires a proactive and multidisciplinary approach. By addressing the challenges associated with treatment limitations and short-term monitoring recommendations while considering alternative therapeutic options like Siponimod, clinicians can optimize outcomes and ensure continuity of care for individuals with MS.

Canine Histiocytic and Hemophagocytic Histiocytic Sarcomas Display KRAS and Extensive PTPN11/SHP2 Mutations and Respond In Vitro to MEK Inhibition by Cobimetinib.

Histiocytic sarcoma (HS) is a rare and highly aggressive cancer in humans and dogs. In dogs, it has a high prevalence in certain breeds, such as Bernese mountain dogs (BMDs) and flat-coated retrievers. Hemophagocytic histiocytic sarcoma (HHS) is a unique form of HS that presents with erythrophagocytosis. Due to its rareness, the study of HHS is very limited, and mutations in canine HHS patients have not been studied to date. In previous work, our research group identified two major PTPN11/SHP2 driver mutations, E76K and G503V, in HS in dogs. Here, we report additional mutations located in exon 3 of PTPN11/SHP2 in both HS and HHS cases, further supporting that this area is a mutational hotspot in dogs and that mutations in tumors and liquid biopsies should be evaluated utilizing comprehensive methods such as Sanger and NextGen sequencing. The overall prevalence of PTPN11/SHP2 mutations was 55.8% in HS and 46.2% in HHS. In addition, we identified mutations in KRAS, in about 3% of HS and 4% of HHS cases. These findings point to the shared molecular pathology of activation of the MAPK pathway in HS and HHS cases. We evaluated the efficacy of the highly specific MEK inhibitor, cobimetinib, in canine HS and HHS cell lines. We found that the IC50 values ranged from 74 to 372 nM, which are within the achievable and tolerable ranges for cobimetinib. This finding positions cobimetinib as a promising potential candidate for future canine clinical trials and enhances our understanding of the molecular defects in these challenging cancers.

Characterization of two melanoma cell lines resistant to BRAF/MEK inhibitors (vemurafenib and cobimetinib).

BACKGROUND: BRAF (v-raf murine sarcoma viral oncogene homolog B1)/MEK (mitogen-activated protein kinase kinase) inhibitors are used for melanoma treatment. Unfortunately, patients treated with this combined therapy develop resistance to treatment quite quickly, but the mechanisms underlying this phenomenon are not yet fully understood. Here, we report and characterize two melanoma cell lines (WM9 and Hs294T) resistant to BRAF (vemurafenib) and MEK (cobimetinib) inhibitors. METHODS: Cell viability was assessed via the XTT test. The level of selected proteins as well as activation of signaling pathways were evaluated using Western blotting. The expression of the chosen genes was assessed by RT-PCR. The distribution of cell cycle phases was analyzed by flow cytometry, and confocal microscopy was used to take photos of spheroids. The composition of cytokines secreted by cells was determined using a human cytokine array. RESULTS: The resistant cells had increased survival and activation of ERK kinase in the presence of BRAF/MEK inhibitors. The IC50 values for these cells were over 1000 times higher than for controls. Resistant cells also exhibited elevated activation of AKT, p38, and JNK signaling pathways with increased expression of EGFR, ErbB2, MET, and PDGFRß receptors as well as reduced expression of ErbB3 receptor. Furthermore, these cells demonstrated increased expression of genes encoding proteins involved in drug transport and metabolism. Resistant cells also exhibited features of epithelial-mesenchymal transition and cancer stem cells as well as reduced proliferation rate and elevated cytokine secretion. CONCLUSIONS: In summary, this work describes BRAF/MEK-inhibitor-resistant melanoma cells, allowing for better understanding the underlying mechanisms of resistance. The results may thus contribute to the development of new, more effective therapeutic strategies.

Siponimod treatment response shows partial BDNF dependency in multiple sclerosis models.

So far, only a small number of medications are effective in progressive multiple sclerosis (MS). The sphingosine-1-phosphate-receptor (S1PR)-1,5 modulator siponimod, licensed for progressive MS, is acting both on peripheral immune cells and in the central nervous system (CNS). So far it remains elusive, whether those effects are related to the neurotrophin brain derived neurotrophic factor (BDNF). We hypothesized that BDNF in immune cells might be a prerequisite to reduce disease activity in experimental autoimmune encephalomyelitis (EAE) and prevent neurotoxicity. MOG35-55 immunized wild type (WT) and BDNF knock-out (BDNFko) mice were treated with siponimod or vehicle and scored daily in a blinded manner. Immune cell phenotyping was performed via flow cytometry. Immune cell infiltration and demyelination of spinal cord were assessed using immunohistochemistry. In vitro, effects on neurotoxicity and mRNA regulation were investigated using dorsal root ganglion cells incubated with EAE splenocyte supernatant. Siponimod led to a dose-dependent reduction of EAE scores in chronic WT EAE. Using a suboptimal dosage of 0.45 µg/day, siponimod reduced clinical signs of EAE independent of BDNF-expression in immune cells in accordance with reduced infiltration and demyelination. Th and Tc cells in secondary lymphoid organs were dose-dependently reduced, paralleled with an increase of regulatory T cells. In vitro, neuronal viability trended towards a deterioration after incubation with EAE supernatant; siponimod showed a slight rescue effect following treatment of WT splenocytes. Neuronal gene expression for CCL2 and CX3CL1 was elevated after incubation with EAE supernatant, which was reversed after siponimod treatment for WT, but not for BNDFko. Apoptosis markers and alternative death pathways were not affected. Siponimod exerts both anti-inflammatory and neuroprotective effects, partially related to BDNF-expression. This might in part explain effectiveness during progression in MS and could be a target for therapy.

Baricitinib alleviates cardiac fibrosis and inflammation induced by chronic sympathetic activation.

Cardiac fibrosis is characterized by the over-proliferation, over-transdifferentiation and over-deposition of extracellular matrix (ECM) of cardiac fibroblasts (CFs). Cardiac sympathetic activation is one of the leading causes of myocardial fibrosis. Meanwhile, cardiac fibrosis is often together with cardiac inflammation, which accelerates fibrosis by mediating inflammatory cytokines secretion. Recently, the Janus kinase/signal transducer and activator of transcription (JAK/STAT3) signaling pathway has been confirmed by its vital role during the progression of cardiac fibrosis. Thus, JAK/STAT3 signaling pathway is thought to be a potential therapeutic target for cardiac fibrosis. Baricitinib (BR), a novel JAK1/2 inhibitor, has been reported excellent effects of anti-fibrosis in multiple fibrotic diseases. However, little is known about whether and how BR ameliorates cardiac fibrosis caused by chronic sympathetic activation. Isoproterenol (ISO), a ß-Adrenergic receptor (ß-AR) nonselective agonist, was used to modulate chronic sympathetic activation in mice. As expected, our results proved that BR ameliorated ISO-induced cardiac dysfunction. Meanwhile, BR attenuated ISO-induced cardiac fibrosis and cardiac inflammation in mice. Moreover, BR also inhibited ISO-induced cardiac fibroblasts activation and macrophages pro-inflammatory secretion. As for mechanism studies, BR reduced ISO-induced cardiac fibroblasts by JAK2/STAT3 and PI3K/Akt signaling, while reduced ISO-induced macrophages pro-inflammatory secretion by JAK1/STAT3 and NF-κB signaling. In summary, BR alleviates cardiac fibrosis and inflammation caused by chronic sympathetic activation. The underlying mechanism involves BR-mediated suppression of JAK1/2/STAT3, PI3K/Akt and NF-κB signaling.

Dissociative Electron Attachment Dynamics of a Promising Cancer Drug Indicates Its Radiosensitizing Potential.

2-Bromo-1-(3,3-dinitroazetidin-1-yl)ethan-1-one (RRx-001) is a hypoxic cell chemotherapeutics with already demonstrated synergism in combined chemo-radiation therapy. The interaction of the compound with secondary low-energy electrons formed in large amounts during the physico-chemical phase of the irradiation may lead to these synergistic effects. The present study focuses on the first step of RRx-001 interaction with low-energy electrons in which a transient anion is formed and fragmented. Combination of two experiments allows us to disentangle the decay of the RRx-001 anion on different timescales. Sole presence of the electron initiates rapid dissociation of NO2 and HNO2 neutrals while NO2 - and Br- anions are produced both directly and via intermediate complexes. Based on our quantum chemical calculations, we propose that bidirectional state switching between π*(NO2) and σ*(C-Br) states explains the experimental spectra. The fast dynamics monitored will impact the condensed phase chemistry of the anion as well.

Trivalent chromium versus baricitinib for rheumatoid arthritis treatment: first phase 2/3 randomized controlled trial, is trivalent chromium the upcoming immune-modulator?

BACKGROUND: Rheumatoid arthritis (RA) is a debilitating disease mainly treated by DMARDs. Baricitinib is one of the emerging DMARDs with strong anti-rheumatic effects but has serious side effects. Trivalent chromium (Cr III) is a natural element with anti-inflammatory properties. Trivalent chromium (Cr III) is introduced for the first time to study its effect and safety in treatment of RA patients and compared to those of baricitinib. METHODS: This is a phase 2/3 randomized controlled trial where RA patients were divided in a ratio of 2:1 according to the newly introduced medication either Cr (III) (group A) or baricitinib (group B). Patients attended three visits on day 0, after 3 weeks and 12 weeks, disease activity was scored. Hands ultrasound was done and reassessed. Side effects were monitored throughout the study. RESULTS: DAS28-CRP improved by 26.9% and 11.8% on third visit for Cr III and baricitinib, respectively (p = 0.001). DAS28-ESR improved by 25.6% and 7.74% on third visit for Cr III and baricitinib, respectively (p = < 0.001). ACR 50 was 18.8% for Cr III and 5.7% for baricitinib on second visit. ACR 70 was 25% for Cr III and 0% for baricitinib on third visit (P = < 0.001). Ultrasound GLOESS, SH, PDUS, joints effusions improved by 38.9%, 38.4%, 56.7% and 74.8% for Cr III, while by 10.5%, 3.75%, 59.6% and worsening of joints effusions happened with baricitinib on third visit. p = 0.022 and 0.002 between groups for GLOESS and SH improvement, respectively. CONCLUSIONS: Cr III has shown very promising fast clinical and sonographic results in treating RA patients which were surprisingly superior to baricitinib in most aspects. Furthermore, Cr III is potentially safe with evidently fewer side effects than baricitinib and other DMARDs, however, long-term safety is still not established. (IRB No.: 00012098- FWA No.: 00018699, Serial number: 040457) ClinicalTrials.gov ID: NCT05545020.

The Nitrofuran-Warhead-Equipped Spirocyclic Azetidines Show Excellent Activity against Mycobacterium tuberculosis.

A series of 21 new 7'H-spiro[azetidine-3,5'-furo [3,4-d]pyrimidine]s substituted at the pyrimidine ring second position were synthesized. The compounds showed high antibacterial in vitro activity against M. tuberculosis. Two compounds had lower minimum inhibitory concentrations against Mtb (H37Rv strain) compared with isoniazid. The novel spirocyclic scaffold shows excellent properties for anti-tuberculosis drug development.

Exploring the interactions of JAK inhibitor and S1P receptor modulator drugs with the human gut microbiome: Implications for colonic drug delivery and inflammatory bowel disease.

The gut microbiota is a complex ecosystem, home to hundreds of bacterial species and a vast repository of enzymes capable of metabolising a wide range of pharmaceuticals. Several drugs have been shown to affect negatively the composition and function of the gut microbial ecosystem. Janus Kinase (JAK) inhibitors and Sphingosine-1-phosphate (S1P) receptor modulators are drugs recently approved for inflammatory bowel disease through an immediate release formulation and would potentially benefit from colonic targeted delivery to enhance the local drug concentration at the diseased site. However, their impact on the human gut microbiota and susceptibility to bacterial metabolism remain unexplored. With the use of calorimetric, optical density measurements, and metagenomics next-generation sequencing, we show that JAK inhibitors (tofacitinib citrate, baricitinib, filgotinib) have a minor impact on the composition of the human gut microbiota, while ozanimod exerts a significant antimicrobial effect, leading to a prevalence of the Enterococcus genus and a markedly different metabolic landscape when compared to the untreated microbiota. Moreover, ozanimod, unlike the JAK inhibitors, is the only drug subject to enzymatic degradation by the human gut microbiota sourced from six healthy donors. Overall, given the crucial role of the gut microbiome in health, screening assays to investigate the interaction of drugs with the microbiota should be encouraged for the pharmaceutical industry as a standard in the drug discovery and development process.

The interaction of the azetidine thiazole side chain with the active site loop (ASL) 3 drives the evolution of IMP metallo-ß-lactamase against tebipenem.

Imipenemase (IMP) metallo-ß-lactamases (MBLs) hydrolyze almost all available ß-lactams including carbapenems and are not inhibited by any commercially available ß-lactamase inhibitor. Tebipenem (TP) pivoxil is the first orally available carbapenem and possesses a unique bicyclic azetidine thiazole moiety located at the R2 position. TP has potent in vitro activity against Enterobacterales producing extended-spectrum and/or AmpC ß-lactamases. Thus far, the activity of TP against IMP-producing strains is understudied. To address this knowledge gap, we explored the structure activity relationships of IMP MBLs by investigating whether IMP-6, IMP-10, IMP-25, and IMP-78 [MBLs with expanded hydrolytic activity against meropenem (MEM)] would demonstrate enhanced activity against TP. Most of the Escherichia coli DH10B strains expressing IMP-1 variants displayed a ≥twofold MIC difference between TP and MEM, while those expressing VIM or NDM variants demonstrated comparable MICs. Catalytic efficiency (kcat/KM) values for the TP hydrolysis by IMP-1, IMP-6, IMP-10, IMP-25, and IMP-78 were significantly lower than those obtained for MEM. Molecular dynamic simulations reveal that V67F and S262G substitutions (found in IMP-78) reposition active site loop 3, ASL-3, to better accommodate the bicyclic azetidine thiazole side chain, allowing microbiological/catalytic activity to approach that of comparison MBLs used in this study. These findings suggest that modifying the R2 side chain of carbapenems can significantly impact hydrolytic stability. Furthermore, changes in conformational dynamics due to single amino acid substitutions should be used to inform drug design of novel carbapenems.

CS12192, a novel JAK3/JAK1/TBK1 inhibitor, attenuates autoimmune dermatoses in murine models.

OBJECTIVE: Autoimmune dermatosis (AID) occurs when the body's immune system attacks skin or tissue, leading to various types of skin disorders or injuries. Recent studies show that Janus kinases (JAKs) play critical roles in autoimmune diseases including AID by regulating multiple cytokine signaling pathways. CS12192, a novel JAK3/JAK1/TBK1 inhibitor, has been reported to exert ameliorative effects in rheumatoid arthritis. However, the efficacy of CS12192 on AID is undetermined. This study aims to investigate the therapeutic efficacy of CS12192 on psoriasis (PSO), systemic lupus erythematosus (SLE) and atopic dermatitis (AD) in mouse models. METHODS: Interleukin-23 (IL-23)-induced PSO model, spontaneous SLE model of MRL/MpJ-Faslpr/J (MRL/lpr) mice, and oxazolone (OXA) and dinitrochlorobenzene (DNCB)-induced murine AD models were used for the evaluation of curative effects of CS12192, respectively. The skin lesion, biochemical parameters, ear thickness, ear weight and histopathology were assessed accordingly. RESULTS: In PSO model, mice treated with CS12192 show reduced ear thickness and ear weight as compared with vehicle. In SLE model, CS12192 ameliorates cutaneous parameters such as lymphadenectasis and skin lesion but not systematic parameters such as proteinuria concentration and score, serum dsDNA and BUN concentration. In AD models, CS12192 dose-dependently improves ear swelling and reduces histological scores, exerting equivalent efficacy with baricitinib, a marketed JAK1/JAK2 inhibitor. CONCLUSION: Our findings suggest that the novel JAK3/JAK1/TBK1 inhibitor CS12192 is potentially to alleviate autoimmune dermatosis.

Re-emergence of T lymphocyte-mediated synaptopathy in progressive multiple sclerosis.

Background: Secondary progressive multiple sclerosis (SPMS) is defined by the irreversible accumulation of disability following a relapsing-remitting MS (RRMS) course. Despite treatments advances, a reliable tool able to capture the transition from RRMS to SPMS is lacking. A T cell chimeric MS model demonstrated that T cells derived from relapsing patients exacerbate excitatory transmission of central neurons, a synaptotoxic event absent during remitting stages. We hypothesized the re-emergence of T cell synaptotoxicity during SPMS and investigated the synaptoprotective effects of siponimod, a sphingosine 1-phosphate receptor (S1PR) modulator, known to reduce grey matter damage in SPMS patients. Methods: Data from healthy controls (HC), SPMS patients, and siponimod-treated SPMS patients were collected. Chimeric experiments were performed incubating human T cells on murine cortico-striatal slices, and recording spontaneous glutamatergic activity from striatal neurons. Homologous chimeric experiments were executed incubating EAE mice T cells with siponimod and specific S1PR agonists or antagonists to identify the receptor involved in siponimod-mediated synaptic recovery. Results: SPMS patient-derived T cells significantly increased the striatal excitatory synaptic transmission (n=40 synapses) compared to HC T cells (n=55 synapses), mimicking the glutamatergic alterations observed in active RRMS-T cells. Siponimod treatment rescued SPMS T cells synaptotoxicity (n=51 synapses). Homologous chimeric experiments highlighted S1P5R involvement in the siponimod's protective effects. Conclusion: Transition from RRMS to SPMS involves the reappearance of T cell-mediated synaptotoxicity. Siponimod counteracts T cell-induced excitotoxicity, emphasizing the significance of inflammatory synaptopathy in progressive MS and its potential as a promising pharmacological target.

Baricitinib ameliorates inflammatory and neuropathic pain in collagen antibody-induced arthritis mice by modulating the IL-6/JAK/STAT3 pathway and CSF-1 expression in dorsal root ganglion neurons.

BACKGROUND: Janus kinase (JAK) inhibitors, such as baricitinib, are widely used to treat rheumatoid arthritis (RA). Clinical studies show that baricitinib is more effective at reducing pain than other similar drugs. Here, we aimed to elucidate the molecular mechanisms underlying the pain relief conferred by baricitinib, using a mouse model of arthritis. METHODS: We treated collagen antibody-induced arthritis (CAIA) model mice with baricitinib, celecoxib, or vehicle, and evaluated the severity of arthritis, histological findings of the spinal cord, and pain-related behaviours. We also conducted RNA sequencing (RNA-seq) to identify alterations in gene expression in the dorsal root ganglion (DRG) following baricitinib treatment. Finally, we conducted in vitro experiments to investigate the direct effects of baricitinib on neuronal cells. RESULTS: Both baricitinib and celecoxib significantly decreased CAIA and improved arthritis-dependent grip-strength deficit, while only baricitinib notably suppressed residual tactile allodynia as determined by the von Frey test. CAIA induction of inflammatory cytokines in ankle synovium, including interleukin (IL)-1ß and IL-6, was suppressed by treatment with either baricitinib or celecoxib. In contrast, RNA-seq analysis of the DRG revealed that baricitinib, but not celecoxib, restored gene expression alterations induced by CAIA to the control condition. Among many pathways changed by CAIA and baricitinib treatment, the interferon-alpha/gamma, JAK-signal transducer and activator of transcription 3 (STAT3), and nuclear factor kappa B (NF-κB) pathways were considerably decreased in the baricitinib group compared with the celecoxib group. Notably, only baricitinib decreased the expression of colony-stimulating factor 1 (CSF-1), a potent cytokine that causes neuropathic pain through activation of the microglia-astrocyte axis in the spinal cord. Accordingly, baricitinib prevented increases in microglia and astrocytes caused by CAIA. Baricitinib also suppressed JAK/STAT3 pathway activity and Csf1 expression in cultured neuronal cells. CONCLUSIONS: Our findings demonstrate the effects baricitinib has on the DRG in relation to ameliorating both inflammatory and neuropathic pain.

Spiro-Azetidine Oxindoles as Long-Acting Injectables for Pre-Exposure Prophylaxis against Respiratory Syncytial Virus Infections.

Respiratory syncytial virus (RSV) is a major cause of hospitalization in infants, the elderly, and immune-compromised patients. While a half-life extended monoclonal antibody and 2 vaccines have recently been approved for infants and the elderly, respectively, options to prevent disease in immune-compromised patients are still needed. Here, we describe spiro-azetidine oxindoles as small molecule RSV entry inhibitors displaying favorable potency, developability attributes, and long-acting PK when injected as an aqueous suspension, suggesting their potential to prevent complications following RSV infection over a period of 3 to 6 months with 1 or 2 long-acting intramuscular (IM) or subcutaneous (SC) injections in these immune-compromised patients.