Substrate-Tuned Domino Annulation for Selective Synthesis of Poly-substituted Benzo[f]imidazo[2,1-a][2,7]naphthyridines and 3-Azaheterocyclic Substituted 2-Arylquinolines.

A domino annulation/oxidation of heterocyclic ketene aminals (HKAs) and 2-aminochalcones has been developed for the selective synthesis of poly-substituted benzo[f]imidazo[2,1-a][2,7]naphthyridines and 3-azaheterocyclic substituted 2-arylquinolines. These reactions proceed well under mild conditions without any additives. Plausible mechanisms for such a polycyclic ring system assembly were also proposed. Moreover, benzo[f]imidazo[2,1-a][2,7]naphthyridine 3g displayed a fluorescence effect, demonstrating the potential applications in organic optical materials.

Preparation of the Key Dolutegravir Intermediate via MgBr2-Promoted Cyclization.

A novel approach for synthesizing the key dolutegravir intermediate is described via MgBr2-promoted intramolecular cyclization. Condensation of commercially available methyl oxalyl chloride and ethyl 3-(N,N-dimethylamino)acrylate afforded the vinylogous amide in an excellent yield. Subsequent substitution by aminoacetaldehyde dimethyl acetal and methyl bromoacetate gave rise to the expected precursor for cyclization, which was promoted by MgBr2 to highly selectively convert into pyridinone diester. The key dolutegravir intermediate was finally prepared by the selective hydrolysis of the corresponding diester via LiOH.

Palladium-Catalyzed H/D Exchange Reaction with 8-Aminoquinoline as the Directing Group: Access to ortho-Selective Deuterated Aromatic Acids and ß-Selective Deuterated Aliphatic Acids.

We develop a palladium-catalyzed H/D exchange reaction with 8-aminoquinoline as the directing group as well as D2O as the source of deuterium atom and solvent. This reaction achieves selectively H/D exchange at the ortho-C-H of aromatic amides and the ß-C-H of aliphatic amide. Ortho-deuterated aromatic acids and ß-deuterated aliphatic acids are obtained by removal of the directing group. And a possible mechanism is also proposed.

A one-pot multicomponent approach to a new series of morphine derivatives and their biological evaluation.

A novel and facile domino reaction has been developed to synthesize a variety of new derivatives from hydromorphone, amines and paraformaldehyde in good yields in a catalyst-free fashion with high atom efficiency. The products show a mixed MOR/DOR biological characteristic which makes them valuable for further study as opioid analgesics.

6-Oxooxazolidine-quinazolines as noncovalent inhibitors with the potential to target mutant forms of EGFR.

Despite the remarkable benefits of gefitinib, the clinical efficacy is eventually diminished due to the acquired point mutations in the EGFR (T790M). To address this unmet medical need, we demonstrated a strategy to prepare a hybrid analogue consisting of the oxooxazolidine ring and the quinazoline scaffold and provided alternative noncovalent inhibitors targeting mutant forms of EGFR. Most of the derivatives displayed moderate to good anti-proliferative activity against gefitinib-resistant NCI-H1975. Some of them exhibited potent EGFR kinase inhibitory activities, especially on EGFR(T790M) and EGFR(L858R) kinases. SAR studies led to the identification of a hit 9a that can target both of the most common EGFR mutants: L858R and T790M. Also, 9a displayed weaker inhibitory against cancer cell lines with low level of EGFR expression and good chemical stability under different pH conditions. The work presented herein showed the potential for developing noncovalent inhibitors targeting EGFR mutants.

Proliferation of parenchymal microglia is the main source of microgliosis after ischaemic stroke.

Stroke induces rapid activation and expansion of microglia, but the main source of microgliosis is controversial. Here we investigated the formation of microgliosis and infiltration of circulating cells in a photothrombosis stroke model by taking advantage of parabiosis and two-photon microscopy. We found that a small population of blood-derived CX3CR1(GFP/+) cells infiltrated the cerebral parenchyma, but these cells did not proliferate and were phenotypically distinguishable from resident microglia. CX3CR1(GFP/+) infiltrating cells also displayed different kinetics from reactive microglia. The number of CX3CR1(GFP/+) infiltrating cells peaked on Day 5 after stroke and then decreased. The decline of these infiltrating cells was associated with an active apoptotic process. In contrast, reactive microglia were recruited to the ischaemic area continuously during the first week after stroke induction. Immunohistology and in vivo two-photon imaging revealed that cells involved in the process of microgliosis were mainly derived from proliferating resident microglia. Expansion of microglia exhibited a consistent pattern and our in vivo data demonstrated for the first time that microglia underwent active division in regions surrounding the ischaemic core. Together, these results indicated that CX3CR1(GFP/+) infiltrating cells and reactive microglia represented two distinct populations of cells with different functions and therapeutic potentials for the treatment of stroke.

A Prostate-Specific Membrane Antigen-Targeting Small Molecule-Drug Conjugate Strategy to Overcome the Hematological Toxicity of Olaparib.

PARP inhibitors have gained attention in the treatment of metastatic castration-resistant prostate cancer, but approximately half of patients have to abort treatment due to severe hematological toxicity. Herein, we proposed a prostate-specific membrane antigen (PSMA)-targeting small molecule-drug conjugate (SMDC) strategy to address this issue. This led to CQ-16, which achieved its targeting to prostate tumor cells through binding to PSMA. Also, CQ-16 retained the PARP inhibitory activity and exhibited highly selective antiproliferative activities between PSMA-positive and PSMA-negative prostate cells. Moreover, the hematological toxicity observed in Olaparib was not showing in the group of CQ-16 even at a high dose of 390 mg/kg. Moreover, oral administration of CQ-16 exerted significant tumor growth inhibition in the 22Rv1 xenograft mouse model. These above findings not only highlight the potential of CQ-16 to overcome the hematological toxicity associated with PARP inhibitors but also provide a strategy to develop an SMDC with enhanced safety profiles.

Discovery of 4-hydroxyl pyrazole derivatives as potent ferroptosis inhibitors.

Ferroptosis, an iron-dependent form of regulated cell death, has been well recognized as a pathogenic mechanism in driving many diseases, such as neurodegenerative disorders, ischemia-reperfusion (I/R) injury. Blocking ferroptosis has been emerging as a feasible therapeutic strategy for the prevention and treatment of these diseases. However, novel potent ferroptosis inhibitors remain to be developed for further clinical applications. In this study, we screened our in-house compound libraries by phenotypic assays and identified a 4-hydroxyl pyrazole derivative HW-3 with good ferroptosis inhibitory activity (EC50 = 120.1 ± 3.5 nM). Based on the structure of HW-3, a series of 4-hydroxyl pyrazole derivatives were further designed and synthesized. Among these compounds, compound 25 could significantly inhibit RSL3-induced ferroptosis with an EC50 value of 8.6 ± 2.2 nM in HT-1080 cells, which was 3-fold more potent than the classical ferroptosis inhibitor ferrostatin-1 (Fer-1) (EC50 = 23.4 ± 1.3 nM). The potent ferroptosis inhibitory activity of compound 25 was further validated in multiple additional cell lines. Our mechanistic study revealed that compound 25 inhibited ferroptosis via intrinsic radical-trapping antioxidative capacity. Taken together, the findings of our study demonstrate 4-hydroxyl pyrazole derivative 25 is a potent ferroptosis inhibitor, which holds a great therapeutic potential for further development.

Identification of 5-Thiocyanatothiazol-2-amines Disrupting WDR5-MYC Protein-Protein Interactions.

MYC amplification is frequently observed in approximately 50% of human cancers, rendering it a highly desired anticancer target. Given the challenge of direct pharmacological inhibiting of MYC, impairing the interaction of MYC and its key cofactor WDR5 has been proposed as a promising strategy for MYC-driven cancer treatment. Herein, we report the discovery of 5-thiocyanatothiazol-2-amines that disrupt the WDR5-MYC interaction. Hit fragments were initially identified in a fluorescence polarization (FP)-based screening of an in-house library, and structural-activity relationship exploration resulted in the lead compounds 4m and 4o with potent inhibitory activities on WDR5-MYC interaction (K i = 2.4 µM for 4m; K i = 1.0 µM for 4o). These compounds were further validated via differential scanning fluorimetry (DSF) and coimmunoprecipitation (Co-IP). Moreover, 4m and 4o exhibited good cellular activities with the IC50 values at the micromolar level (IC50 = 0.71-7.40 µM) against multiple MYC-driven cancer cell lines. Our findings afforded a potential small molecule blocking the WDR5-MYC interaction.

Integrative clinical and preclinical studies identify FerroTerminator1 as a potent therapeutic drug for MASH.

The complex etiological factors associated with metabolic dysfunction-associated fatty liver disease (MAFLD), including perturbed iron homeostasis, and the unclear nature by which they contribute to disease progression have resulted in a limited number of effective therapeutic interventions. Here, we report that patients with metabolic dysfunction-associated steatohepatitis (MASH), a pathological subtype of MAFLD, exhibit excess hepatic iron and that it has a strong positive correlation with disease progression. FerroTerminator1 (FOT1) effectively reverses liver injury across multiple MASH models without notable toxic side effects compared with clinically approved iron chelators. Mechanistically, our multi-omics analyses reveal that FOT1 concurrently inhibits hepatic iron accumulation and c-Myc-Acsl4-triggered ferroptosis in various MASH models. Furthermore, MAFLD cohort studies suggest that serum ferritin levels might serve as a predictive biomarker for FOT1-based therapy in MASH. These findings provide compelling evidence to support FOT1 as a promising novel therapeutic option for all stages of MAFLD and for future clinical trials.

Design and synthesis of 7-membered lactam fused hydroxypyridinones as potent metal binding pharmacophores (MBPs) for inhibiting influenza virus PAN endonuclease.

Since influenza virus RNA polymerase subunit PAN is a dinuclear Mn2+ dependent endonuclease, metal-binding pharmacophores (MBPs) with Mn2+ coordination has been elucidated as a promising strategy to develop PAN inhibitors for influenza treatment. However, few attentions have been paid to the relationship between the optimal arrangement of the donor atoms in MBPs and anti-influenza A virus (IAV) efficacy. Given that, the privileged hydroxypyridinones fusing a seven-membered lactam ring with diverse side chains, chiral centers or cyclic systems were designed and synthesized. A structure-activity relationship study resulted in a hit compound 16l (IC50 = 2.868 ± 0.063 µM against IAV polymerase), the seven-membered lactam ring of which was fused a pyrrolidine ring. Further optimization of the hydrophobic binding groups on 16l afforded a lead compound (R, S)-16s, which exhibited a 64-fold more potent inhibitory activity (IC50 = 0.045 ± 0.002 µM) toward IAV polymerase. Moreover, (R, S)-16s demonstrated a potent anti-IAV efficacy (EC50 = 0.134 ± 0.093 µM) and weak cytotoxicity (CC50 = 15.35 µM), indicating the high selectivity of (R, S)-16s. Although the lead compound (R, S)-16s exhibited a little weaker activity than baloxavir, these findings illustrated the utility of a metal coordination-based strategy in generating novel MBPs with potent anti-influenza activity.

Libraries from Libraries: A Series of Sulfonamide Linked Heterocycles Derived from the Same Scaffold.

A libraries from libraries approach is described for the synthesis of five different sulfonamide linked scaffolds. Four of the scaffolds are sulfonamides linked to heterocycles; piperazine, thiourea, cyclic guanidine, and dimethyl cyclic guanidine. The fifth scaffold is a polyamine linked sulfonamide. Three different diversity positions were effectively incorporated into each scaffold providing a number of different compounds with good yields and purity.

Synthesis and structure-activity optimization of 7-azaindoles containing aza-ß-amino acids targeting the influenza PB2 subunit.

The PB2 subunit of influenza virus polymerase has been demonstrated as a promising drug target for anti-influenza therapy. In this work, 7-azaindoles containing aza-ß3- or ß2,3 -amino acids were synthesized possessing a good binding affinity of PB2. The aza-ß-amino acid moieties with diverse size, shape, steric hindrance and configuration were investigated. Then a lead HAA-09 was validated, and the attached aza-ß3-amino acid moiety with acyclic tertiary carbon side chain well occupied in the key hydrophobic cavity of PB2_cap binding domain. Importantly, HAA-09 displays potent polymerase inhibition capacity, low cytotoxicity (selectivity index up to 2915) as well as robust anti-viral activity against A/WSN/33 (H1N1) virus and oseltamivir-resistant H275Y variant. Moreover, HAA-09 exhibited druggability with high plasma stability (t1/2 ≥ 12 h) and no obvious hERG inhibition (IC50 > 10 µM). Also, HAA-09 demonstrated a favorable safety profile when orally administrated in healthy mice at a high dose of 40 mg/kg QD for consecutive 3 days. Besides, in vivo therapeutic efficacy (85.7% survival observed at the day 15 post infection) was demonstrated when HAA-09 was administrated orally at 12.5 mg/kg BID starting 48 h post infection for 9 days. These data support that exploring the interactions between side chains on aza-ß3- or ß2,3 -amino acid moieties and hydrophobic pocket of PB2_cap binding domain is a potential medicinal chemistry strategy for developing potent PB2 inhibitors.

Targeting Labile Iron-Mediated Ferroptosis Provides a Potential Therapeutic Strategy for Rhabdomyolysis-Induced Acute Kidney Injury.

Acute kidney injury (AKI) is a global health problem that occurs in a variety of clinical settings. Despite some advances in supportive clinical care, no medicinal intervention has been demonstrated to reliably prevent AKI thus far. Therefore, it is highly necessary to investigate the pathophysiology and mechanisms involved in AKI for the discovery of therapeutics. In the current study, a robust change in the level of renal malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) and elevated renal iron levels were observed in murine rhabdomyolysis-induced AKI (RM-AKI), which supports a pathogenic role of labile iron-mediated ferroptosis and provides a chance to utilize iron chelation for RM-AKI prevention. Given that the existing small molecule-based iron chelators did not show promising preventative effects against RM-AKI, we further designed and synthesized a new hydroxypyridinone-based iron chelator to potently inhibit labile iron-mediated ferroptosis. Lead compound AKI-02 was identified, which remarkably protected renal proximal tubular epithelial cells from ferroptosis as well as showed excellent iron chelation ability. Moreover, administration of AKI-02 led to renal function recovery, a result that was substantiated by the decreased contents of BUN and creatinine, as well as the reduced labile iron level and improved histopathology. Thus, our studies highlighted that targeting labile iron-mediated ferroptosis could provide therapeutic benefits against RM-AKI.

Metformin potentiates nephrotoxicity by promoting NETosis in response to renal ferroptosis.

Given the rapidly aging population, aging-related diseases are becoming an excessive burden on the global healthcare system. Metformin has been shown to be beneficial to many age-related disorders, as well as increase lifespan in preclinical animal models. During the aging process, kidney function progressively declines. Currently, whether and how metformin protects the kidney remains unclear. In this study, among longevity drugs, including metformin, nicotinamide, resveratrol, rapamycin, and senolytics, we unexpectedly found that metformin, even at low doses, exacerbated experimentally-induced acute kidney injury (AKI) and increased mortality in mice. By single-cell transcriptomics analysis, we found that death of renal parenchymal cells together with an expansion of neutrophils occurs upon metformin treatment after AKI. We identified programmed cell death by ferroptosis in renal parenchymal cells and blocking ferroptosis, or depleting neutrophils protects against metformin-induced nephrotoxicity. Mechanistically, upon induction of AKI, ferroptosis in renal parenchymal cells initiates the migration of neutrophils to the site of injury via the surface receptor CXCR4-bound to metformin-iron-NGAL complex, which results in NETosis aggravated AKI. Finally, we demonstrated that reducing iron showed protective effects on kidney injury, which supports the notion that iron plays an important role in metformin-triggered AKI. Taken together, these findings delineate a novel mechanism underlying metformin-aggravated nephropathy and highlight the mechanistic relationship between iron, ferroptosis, and NETosis in the resulting AKI.

ACSL5, a prognostic factor in acute myeloid leukemia, modulates the activity of Wnt/ß-catenin signaling by palmitoylation modification.

Acyl-CoA synthetase long chain family member 5 (ACSL5), is a member of the acyl-CoA synthetases (ACSs) family that activates long chain fatty acids by catalyzing the synthesis of fatty acyl-CoAs. The dysregulation of ACSL5 has been reported in some cancers, such as glioma and colon cancers. However, little is known about the role of ACSL5 in acute myeloid leukemia (AML). We found that the expression of ACSL5 was higher in bone marrow cells from AML patients compared with that from healthy donors. ACSL5 level could serve as an independent prognostic predictor of the overall survival of AML patients. In AML cells, the ACSL5 knockdown inhibited cell growth both in vitro and in vivo. Mechanistically, the knockdown of ACSL5 suppressed the activation of the Wnt/ß-catenin pathway by suppressing the palmitoylation modification of Wnt3a. Additionally, triacsin c, a pan-ACS family inhibitor, inhibited cell growth and robustly induced cell apoptosis when combined with ABT-199, the FDA approved BCL-2 inhibitor for AML therapy. Our results indicate that ACSL5 is a potential prognosis marker for AML and a promising pharmacological target for the treatment of molecularly stratified AML.

Junctophilin 2 knockdown interfere with mitochondrium status in ESC-CMs and cardiogenesis of ES cells.

In the present study, we explored the possible links between Junctophilin 2 (Jp2) and the mitochondrium-sarcoplasmic reticulum (SR) interaction in embryonic stem cell-derived cardiomyocytes (ESC-CMs), as well as the role of Jp2 in cardiogenesis of ES cells. We found that Ca(2+) transient was abnormal and mitochondria were de-energized within siJp2 ESC-CMs. The essential juxtaposition structure of mitochondrium with SR was destroyed accompanied by selectively downregulation of Pgc-1α, Nrf-1, and Mfn-2. Impaired co-localization of the JP2 and sarcomeres (α-Actinin or Troponin-T) appeared in embryoid bodies (EBs) after Jp2 knockdown. Calsequestrin2 and ryanodine receptor 2 within SR were expressed as early as the initiation of differentiation, while triadin and caveolin3 within t-tubules (TTs) did not appear until the terminal, indicating that JP2 probably did not contribute to anchoring the SR to TTs at the early cardiogenesis stage as usual. In addition, Jp2 knockdown selectively decreased gene transcription toward cardiogenesis (Brachyury, Isl1, and Nkx2.5), subsequently weaken EB beating activity by 60%. Taken together, reducing JP2 expression in ESC-CMs resulted in impaired mitochondrial status due to either abnormal cellular Ca(2+) homeostasis or disturbing of juxtaposition. A sensitive time window of JP2 necessary in cardiac differentiation was found at early stage via an extra non-TTs/SR anchor-dependent role.

2,3,4,6-Tetra-O-acetyl-ß-d-galacto-pyrano-syl butyrate.

The title compound, C(18)H(26)O(11), was synthesized by a condensation reaction of 2,3,4,6-tetra-O-acetyl-α-d-galactopyranosyl bromide and butyric acid. The acet-oxy-methyl and butyrate groups are located on the same side of the pyran ring, showing the ß configuration for the d-glycosyl ester; the butyl group adopts an extend conformation, the C-C-C-C torsion angle being 179.1 (7)°. In the crystal, the mol-ecules are linked by weak C-H⋯O hydrogen bonds.

[Establishment of optimized neuronal differentiation-promoting model derived from P19 embryonic carcinoma cells].

OBJECTIVE: To establish an optimized primary drug screen model of neuronal differentiation using P19 embryonal carcinoma cells. METHODS: The final concentration of retinoid acid (RA), days of suspension culture, manner of adherent culture, suitable cell density and adherent culture medium were tested, respectively. Two stages of neuronal differentiation were examined based on morphological changes and immunocytochemistry analysis of neuronal specific protein ß-tubulin III. RESULTS: On d 8 of differentiation culture, neuron-like cells were observed with final concentration of 1 µmol/L RA. Neuron-like network was formed on d 16 of neuronal differentiation. ß-tubulin III was positively stained on both stages, indicating P19 cells were differentiated into neurons. CONCLUSION: The model using RA to induce P19 embryonic carcinoma cells to differentiate into neuron-like cells has been successfully established, which may provide a rapid, phenotypic cell-based platform for primary screening of neurogenesis-promoting drugs.

Approaches for discovery of small-molecular antivirals targeting to influenza A virus PB2 subunit.

Influenza is an acute respiratory infectious disease caused by influenza virus, leading to huge morbidity and mortality in humans worldwide. Despite the availability of antivirals in the clinic, the emergence of resistant strains calls for antivirals with novel mechanisms of action. The PB2 subunit of the influenza A virus polymerase is a promising target because of its vital role in the 'cap-snatching' mechanism. In this review, we summarize the technologies and medicinal chemistry strategies for hit identification, hit-to-lead and lead-to-candidate optimization, and current challenges in PB2 inhibitor development, as well as offering insights for the fight against drug resistance.