Amino-substituted thalidomide analogs: potent inhibitors of TNF-alpha production

Development and validation of stability-indicating UHPLC-UV-MS tandem methods for lenalidomide assay, related substances, and genotoxic impurity monitoring

Lenalidomide, a potent immunomodulatory drug, is widely used in the treatment of myelodysplastic syndrome. To investigate its degradation behavior under stress and stability testing conditions, we developed and validated a novel stability-indicating ultra-performance liquid chromatography (UHPLC)-UV-MS tandem method with high specificity, precision, accuracy, and robustness. An Acquity UPLC Phenyl column (100 × 2.1 mm, 1.7 µm) was used for impurity profiling and quantification of lenalidomide at a detection wavelength of 254 nm, with an injection volume of 1.0 µL and controlled sample and column temperatures of 15 °C and 30 °C, respectively. The diluent consisted of 0.1 % formic acid and acetonitrile (90:10, v/v), while the mobile phases were 0.1 % formic acid (Mobile Phase A) and acetonitrile (Mobile Phase B). A 20-minute gradient elution at a flow rate of 0.2 mL/min was used for impurity analysis, whereas a 7-minute gradient at 0.3 mL/min was applied for assay determination. The method demonstrated good linearity for all analytes, ensuring reliable quantification. Stress and photostability studies revealed that lenalidomide was stable under high temperatures (105 °C for 10 days) and daylight/UV exposure but exhibited significant degradation under hydrolytic and oxidative conditions. Hydrolysis led to the formation of major degradation products A, B, and E, whereas oxidative stress conditions generated impurities C (-NH2 → -NO2) and I (-NH2 → -NH-OH). Methanol, commonly used in lenalidomide synthesis and analytical methods, was found to play a critical role in impurity formation. Methanolysis products J and K were identified as constitutional isomers arising from the ring-opening of the glutarimide moiety, which was confirmed by UHPLC-Q-TOF-MS and NMR analyses. The UHPLC-UV-MS method also reliably monitored the potentially genotoxic impurity G, classified as a Class 2 impurity according to ICH M7 guidelines, ensuring its levels remained below the Toxicological Threshold Concern (TTC, 1.5 µg/day, 60 ppm) for patient safety as per health authority requirements. This comprehensive analytical approach not only ensures the stability and safety of lenalidomide but also provides critical insights into its degradation pathways. The findings contribute to improved impurity control strategies, manufacturing process optimization, and regulatory compliance, benefiting the broader class of glutarimide-containing drug substances such as pomalidomide and thalidomide.

T lymphocyte plasticity in chronic inflammatory diseases: The emerging role of the Ikaros family as a key Th17-Treg switch

T helper (Th) 17 and regulatory T (Treg) cells are highly plastic CD4+ Th cell subsets, being able not only to actively adapt to their microenvironment, but also to interconvert, acquiring mixed identity markers. These phenotypic changes are underpinned by transcriptional control mechanisms, chromatin reorganization events and epigenetic modifications, that can be hereditable and stable over time. The Ikaros family of transcription factors have a predominant role in T cell subset specification through mechanisms of transcriptional program regulation that enable phenotypical diversification. They are crucial factors in maintaining Th17/Treg balance and therefore, homeostatic conditions in the tissues. However, they are also implicated in pathogenic processes, where their transcriptional repression contributes to the control of autoimmune processes. In this review, we discuss how T cell fate, specifically in humans, is regulated by the Ikaros family and its interplay with additional factors like the Notch signaling pathway, gut microbiota and myeloid-T cell interactions. Further, we highlight how the transcriptional activity of the Ikaros family impacts the course of T cell mediated chronic inflammatory diseases like rheumatoid and psoriatic arthritis, inflammatory bowel disease, systemic lupus erythematosus and multiple sclerosis. We conclude by discussing recently developed therapeutics designed to target Ikaros family members.

β-d-Ribofuranose as a Core with a Phosphodiester Moiety as the Enzyme Recognition Site for Codrug Development

An ideal codrug design should be able to control drug release, offer selectivity during drug delivery, and break down into non-toxic fragments after biodegradation. Our design incorporates d-ribofuranose as the core, with carbamate and carbonate groups as linking joints, a phosphodiester moiety as an enzyme recognition site, and lenalidomide and paclitaxel as the constituent drugs. The codrug synthesis involves seven steps with a 33% overall yield. The target codrug increases its water solubility 685 times versus paclitaxel.

Protocol for the comprehensive biochemical and cellular profiling of small-molecule degraders using CoraFluor TR-FRET technology

Comprehensive characterization of small-molecule degraders, including binary and ternary complex formation and degradation efficiency, is critical for bifunctional ligand development and understanding structure-activity relationships. Here, we present a protocol for the biochemical and cellular profiling of small-molecule degraders based on CoraFluor time-resolved fluorescence resonance energy transfer (TR-FRET) technology. We describe steps for labeling antibodies and proteins, tracer saturation binding, binary target engagement, ternary complex profiling, and off-rate determination. We then detail procedures for the quantification of endogenous and GFP fusion proteins in cell lysates. For complete details on the use and execution of this protocol, please refer to Ichikawa et al.1.

Design, Synthesis, and Antibacterial Evaluation of Novel Isoindolin-1-ones Derivatives Containing Piperidine Fragments

A series of novel isoindoline-1-one derivatives containing piperidine moiety were designed and synthesized using natural compounds as raw materials, and their biological activities were tested for three bacterial and three fungal pathogens. These derivatives exhibited good against phytopathogenic bacteria activities against Pseudomonas syringae pv actinidiae (Psa) and Xanthomonas axonopodis pv.citri (Xac). Some compounds exhibited excellent antibacterial activities against Xanthomonas oryzae pv oryzae (Xoo). The dose of Y8 against Xoo (the maximum half lethal effective concentration (EC50) = 21.3 μg/mL) was better than that of the thiediazole copper dose (EC50 = 53.3 μg/mL). Excitingly, further studies have shown that the molecular docking of Y8 with 2FBW indicates that it can fully locate the interior of the binding pocket through hydrogen bonding and hydrophobic interactions, thereby enhancing its anti-Xoo activity. Scanning electron microscopy (SEM) studies revealed that Y8 induced the Xoo cell membrane collapse. Moreover, the proteomic results also indicate that Y8 may be a multifunctional candidate as it affects the formation of bacterial Xoo biofilms, thereby exerting antibacterial effects.

Crbn-based molecular Glues: Breakthroughs and perspectives

CRBN is a substrate receptor for the Cullin Ring E3 ubiquitin ligase 4 (CRL4) complex. It has been observed that CRBN can be exploited by small molecules to facilitate the recruitment and ubiquitination of non-natural CRL4 substrates, resulting in the degradation of neosubstrate through the ubiquitin-proteasome system. This phenomenon, known as molecular glue-induced protein degradation, has emerged as an innovative therapeutic approach in contrast to traditional small-molecule drugs. One key advantage of molecular glues, in comparison to conventional small-molecule drugs adhering to Lipinski's Rule of Five, is their ability to operate without the necessity for specific binding pockets on target proteins. This unique characteristic empowers molecular glues to interact with conventionally intractable protein targets, such as transcription factors and scaffold proteins. The ability to induce the degradation of these previously elusive targets by hijacking the ubiquitin-proteasome system presents a promising avenue for the treatment of recalcitrant diseases. Nevertheless, the rational design of molecular glues remains a formidable challenge due to the limited understanding of their mechanisms and actions. This review offers an overview of recent advances and breakthroughs in the field of CRBN-based molecular glues, while also exploring the prospects for a systematic approach to designing these compounds.

The story of the development of generic lenalidomide: How one company thwarted the Hatch-Waxman Act to generate billions of dollars in revenue

Lenalidomide (Revlimid®) was originally approved by the Food and Drug Administration (FDA) in 2005, however, a generic version was not available until 2022. In that time, the price of lenalidomide has increased more than 20 times, and in 2021 alone, it accounted for >$5.8 billion dollars in Medicare Part D spending. This was a direct consequence of legal tactics employed by the manufacturer to thwart development of generic formulations of lenalidomide. In this report, we review the clinical development of lenalidomide, provide background on generic drug manufacturing in the United States (US), describe the steps that the manufacturer took to prevent entry of generic lenalidomide into the US market, and advocate for legislative reform of the FDA approval process and patent law protections in the US.

Quantification of Pomalidomide Using Conventional and Eco-Friendly Stability-Indicating HPTLC Assays: A Contrast of Validation Parameters

High-performance thin-layer chromatographic (HPTLC) assays for pomalidomide (PMD) measurement are lacking in the published database. Furthermore, eco-friendly stability-indicating analytical assays for PMD measurement are also lacking in the published database. In order to detect PMD in commercial products more accurately and sustainably than the conventional normal-phase HPTLC (NP-HPTLC) assay, an effort was made to design and verify a sensitive and eco-friendly reversed-phase HPTLC (RP-HPTLC) assay. The silica gel 60 NP-18F254S and 60 RP-18F254S plates were used as the stationary phases for NP-HPTLC and RP-HPTLC methods, respectively. The solvent system for NP-HPTLC was chloroform-methanol (90:10 v/v). However, the solvent system for RP-HPTLC was ethanol-water (75:25 v/v). The greenness scores for both assays were measured by AGREE approach. PMD measurement was performed for both assays at 372 nm. In the 50-600 and 20-1000 ng/band ranges, the NP-HPTLC and RP-HPTLC methods were linear for PMD measurement. The RP-HPTLC assay was superior to the NP-HPTLC method for measuring PMD in terms of sensitivity, accuracy, precision, and robustness. The ability of both methods to identify PMD in the presence of its degradation products suggests that both methods have stability-indicating features. When employing the NP-HPTLC and RP-HPTLC assays, respectively, the assay for PMD in commercial capsules was 88.68 and 98.83%. The AGREE scores for NP-HPTLC and RP-HPTLC assays were calculated to be 0.44 and 0.82, respectively, suggesting an outstanding greenness characteristic of the RP-HPTLC method than the NP-HPTLC method. The RP-HPTLC method was found to be superior to the NP-HPTLC method based on these findings. Therefore, the RP-HPTLC method could be successfully applied for the determination of PMD in pharmaceutical products.

LY103, a pomalidomide derivative, alleviates taxol resistance in NSCLC via energy metabolism crosstalk and tumor microenvironment intervention

In this study, we identified HIF 1α as a potential target for reversing taxol resistance in lung cancer by combining bioinformatics analysis with pharmacological analysis. Furthermore, pomalidomide derivative LY103 was also be synthesized by introducing an isatin analogue into the amino terminal ofpomalidomide, and it has a broad antitumor spectrum and showed excellent activity against A549/Taxol cells (IC50 = 6.33 ± 0.51 μM). The results of molecular docking showed that not only LY103 was inclined to bind to HIF 1α stably, it could also form multiple hydrogen bonds with VAL376, ASP256, ILE454, and GLU455 of HIF 1α even was reduced to LY103-NH2 by nitroreductase, which was further stabilized the complex formed by them, thereby inhibiting the activity of HIF 1α. LY103 was able to significantly induce DNA damage and inhibit angiogenesis. Concurrently, LY103 activated the immune response, reduced the expression of cytokines TNF-α, IL-6, and IL-1β, thus might be inhibit the proliferation and metastasis of tumor cells. Pharmacological analysis proved that LY103 led to cell apoptosis through the mitochondrial pathway, and its combination with taxol significantly promoted this process. In general, the consumption of glutathione, the crosstalk of energy metabolism, and the improvement of the tumor microenvironment caused by LY103 eventually led to the decrease of ABCC1 protein expression and the drug resistance was reversed. The rational design of LY103 provided a basis for the application of nitro compounds in the treatment of hypoxic tumors and the reversal of taxol resistance.

Alzheimer's disease and neuroinflammation: will new drugs in clinical trials pave the way to a multi-target therapy?

Despite extensive research, no disease-modifying therapeutic option, able to prevent, cure or halt the progression of Alzheimer's disease [AD], is currently available. AD, a devastating neurodegenerative pathology leading to dementia and death, is characterized by two pathological hallmarks, the extracellular deposits of amyloid beta (Aβ) and the intraneuronal deposits of neurofibrillary tangles (NFTs) consisting of altered hyperphosphorylated tau protein. Both have been widely studied and pharmacologically targeted for many years, without significant therapeutic results. In 2022, positive data on two monoclonal antibodies targeting Aβ, donanemab and lecanemab, followed by the 2023 FDA accelerated approval of lecanemab and the publication of the final results of the phase III Clarity AD study, have strengthened the hypothesis of a causal role of Aβ in the pathogenesis of AD. However, the magnitude of the clinical effect elicited by the two drugs is limited, suggesting that additional pathological mechanisms may contribute to the disease. Cumulative studies have shown inflammation as one of the main contributors to the pathogenesis of AD, leading to the recognition of a specific role of neuroinflammation synergic with the Aβ and NFTs cascades. The present review provides an overview of the investigational drugs targeting neuroinflammation that are currently in clinical trials. Moreover, their mechanisms of action, their positioning in the pathological cascade of events that occur in the brain throughout AD disease and their potential benefit/limitation in the therapeutic strategy in AD are discussed and highlighted as well. In addition, the latest patent requests for inflammation-targeting therapeutics to be developed in AD will also be discussed.

Bone marrow microenvironment- induced regulation of Bcl-2 family members in multiple myeloma (MM): Therapeutic implications

In Multiple Myeloma (MM) the finely tuned homeostasis of the bone marrow (BM) microenvironment is disrupted. Evasion of programmed cell death (apoptosis) represents a hallmark of cancer. Besides genetic aberrations, the supportive and protective MM BM milieu, which is constituted by cytokines and growth factors, intercellular and cell: extracellular matrix (ECM) interactions and exosomes, in particular, plays a key role in the abundance of pro-survival members of the Bcl-2 family (i.e., Mcl-1, Bcl-2, and Bcl-xL) in tumor cells. Moreover, microenvironmental cues have also an impact on stability- regulating post-translational modifications of anti-apoptotic proteins including de/phosphorylation, polyubiquitination; on their intracellular binding affinities, and localization. Advances of our molecular knowledge on the escape of cancer cells from apoptosis have informed the development of a new class of small molecules that mimic the action of BH3-only proteins. Indeed, approaches to directly target anti-apoptotic Bcl-2 family members are among today's most promising therapeutic strategies and BH3-mimetics (i.e., venetoclax) are currently revolutionizing not only the treatment of CLL and AML, but also hold great therapeutic promise in MM. Furthermore, approaches that activate apoptotic pathways indirectly via modification of the tumor microenvironment have already entered clinical practice. The present review article will summarize our up-to-date knowledge on molecular mechanisms by which the MM BM microenvironment, cytokines, and growth factors in particular, mediates tumor cell evasion from apoptosis. Moreover, it will discuss some of the most promising science- derived therapeutic strategies to overcome Bcl-2- mediated tumor cell survival in order to further improve MM patient outcome.

Design, Synthesis, and Evaluation of Isoindoline Derivatives as New Antidepressant Agents

Background:

Isoindoline derivatives exhibit a wide range of biological activities and have attracted considerable attention. However, few studies have been conducted on their antidepressant activity.

Objective:

Here, we designed and synthesized a series of isoindoline derivatives and studied their antidepressant activities.

Method:

Forced swimming test (FST) and tail suspension test (TST) were used to evaluate the antidepressant activity of the target compounds. The most active compound was used to evaluate the exploratory activity of the animals by the open-field test. 5-HT concentration was estimated to evaluate if the compound has an effect on the mice brain by using ELISA. The biological activities of the compounds were verified by molecular docking studies. The pharmacokinetic properties of the target compounds were predicted by Discovery Studio (DS) 2020.

Results:

The results of the pharmacological experiments showed that most isoindoline derivatives exhibited significant antidepressant activity. Among these compounds, compound 4j showed the highest antidepressant activity. The results of the measurement of 5-HT levels in the brains of mice indicate that the antidepressant activity of isoindoline derivatives may be mediated by elevated 5-HT levels. Compound 4j was used in molecular docking experiments to simulate the possible interaction of these compounds with the 5-HT1A receptor. The results demonstrated that compound 4j had a significant interaction with amino acids around the active site of the 5-HT1A receptor in the homology model.

Conclusion:

Isoindoline derivatives synthesized in this study have a significant antidepressant activity. These findings can be useful in the design and synthesis of novel antidepressants.

(S)-3-aminopiperidine-2,6-dione is a biosynthetic intermediate of microbial blue pigment indigoidine

The biosynthetic investigations of microbial natural products continuously provide powerful biocatalysts for the preparation of valuable chemicals. Practical methods for preparing (S)-3-aminopiperidine-2,6-dione (2), the pharmacophore of thalidomide (1) and its analog drugs, are highly desired. To develop a biocatalyst for producing (S)-2, we dissected the domain functions of IdgS, which is responsible for the biosynthesis of indigoidine (3), a microbial blue pigment that consists of two 2-like moieties. Our data supported that the L-glutamine tethered to the indigoidine assembly line is first offloaded and cyclized by the thioesterase domain to form (S)-2, which is then dehydrogenated by the oxidation (Ox) domain and finally dimerized to yield 3. Based on this, we developed an IdgS-derived enzyme biocatalyst, IdgS-Ox* R539A, for preparing enantiomerically pure (S)-2. As a proof of concept, one-pot chemoenzymatic synthesis of 1 was achieved by combining the biocatalytic and chemical approaches.

Lenalidomide Improves Cognitive Function and Reduces Immune Reconstitution Inflammatory Syndrome in HIV-1-Related Cryptococcal Meningitis

Cryptococcal meningitis (CM) is a common opportunistic infection in patients with acquired immune deficiency syndrome. Although there is a standardized treatment for CM, some patients still have CM-associated immune reconstitution inflammatory syndrome (IRIS) after anti-cryptococcal and antiretroviral therapy, which manifests as cognitive impairment. We report two cases of CM-associated IRIS in human immunodeficiency virus (HIV) patients that were treated with lenalidomide. The treatment yielded a rapid clinical remission and improved cognitive function in both patients; their Montreal Cognitive Assessment (MoCA) and International HIV Dementia Scale (IHDS) scores improved. Furthermore, we evaluated changes in 32 cytokines in the cerebrospinal fluid of two patients and found that both MoCA and IHDS were significantly negatively correlated with inflammation-related factors (growth-related oncogene, interleukin [IL]-10, IL-2, IL-8, macrophage inflammatory protein-1β, tumor necrosis factor [TNF]-α) and significantly positively correlated with dementia-related factors (αβ42 and total tau). Our study reveals the potential of lenalidomide in treating cognitive impairment caused by immune-mediated inflammation in patients with HIV-CM. Moreover, we speculate that lenalidomide improves cognitive function by regulating intracranial inflammation via multiple pathways, not only by TNF-α blocking.

Second Sphere Interactions in Amyloidogenic Diseases

Amyloids are protein aggregates bearing a highly ordered cross β structural motif, which may be functional but are mostly pathogenic. Their formation, deposition in tissues and consequent organ dysfunction is the central event in amyloidogenic diseases. Such protein aggregation may be brought about by conformational changes, and much attention has been directed toward factors like metal binding, post-translational modifications, mutations of protein etc., which eventually affect the reactivity and cytotoxicity of the associated proteins. Over the past decade, a global effort from different groups working on these misfolded/unfolded proteins/peptides has revealed that the amino acid residues in the second coordination sphere of the active sites of amyloidogenic proteins/peptides cause changes in H-bonding pattern or protein-protein interactions, which dramatically alter the structure and reactivity of these proteins/peptides. These second sphere effects not only determine the binding of transition metals and cofactors, which define the pathology of some of these diseases, but also change the mechanism of redox reactions catalyzed by these proteins/peptides and form the basis of oxidative damage associated with these amyloidogenic diseases. The present review seeks to discuss such second sphere modifications and their ramifications in the etiopathology of some representative amyloidogenic diseases like Alzheimer's disease (AD), type 2 diabetes mellitus (T2Dm), Parkinson's disease (PD), Huntington's disease (HD), and prion diseases.

E3 ligase ligand chemistries: from building blocks to protein degraders

In recent years, proteolysis-targeting chimeras (PROTACs), capable of achieving targeted protein degradation, have proven their great therapeutic potential and usefulness as molecular biology tools. These heterobifunctional compounds are comprised of a protein-targeting ligand, an appropriate linker, and a ligand binding to the E3 ligase of choice. A successful PROTAC induces the formation of a ternary complex, leading to the E3 ligase-mediated ubiquitination of the targeted protein and its proteasomal degradation. In over 20 years since the concept was first demonstrated, the field has grown substantially, mainly due to the advancements in the discovery of non-peptidic E3 ligase ligands. Development of small-molecule E3 binders with favourable physicochemical profiles aided the design of PROTACs, which are known for breaking the rules of established guidelines for discovering small molecules. Synthetic accessibility of the ligands and numerous successful applications led to the prevalent use of cereblon and von Hippel-Lindau as the hijacked E3 ligase. However, the pool of over 600 human E3 ligases is full of untapped potential, which is why expanding the artillery of E3 ligands could contribute to broadening the scope of targeted protein degradation. In this comprehensive review, we focus on the chemistry aspect of the PROTAC design process by providing an overview of liganded E3 ligases, their chemistries, appropriate derivatisation, and synthetic approaches towards their incorporation into heterobifunctional degraders. By covering syntheses of both established and underexploited E3 ligases, this review can serve as a chemistry blueprint for PROTAC researchers during their future ventures into the complex field of targeted protein degradation.

Pathway network of pyroptosis and its potential inhibitors in acute kidney injury

Acute kidney injury (AKI) is a worldwide problem, and there is no effective drug to eliminate AKI. The death of renal cells is an important pathological basis of intrinsic AKI. At present, targeted therapy for TEC death is a research hotspot in AKI therapy. There are many ways of cell death involved in the occurrence and development of AKI, such as apoptosis, necrosis, ferroptosis, and pyroptosis. This article mainly focuses on the role of pyroptosis in AKI. The assembly and activation of NLRP3 inflammasome is a key event in the occurrence of pyroptosis, which is affected by many factors, such as the activation of the NF-κB signaling pathway, mitochondrial instability and excessive endoplasmic reticulum (ER) stress. The activation of NLRP3 inflammasome can trigger its downstream inflammatory cytokines, which will lead to pyroptosis and eventually induce AKI. In this paper, we reviewed the possible mechanism of pyroptosis in AKI and the potential effective inhibitors of various key targets in this process. It may provide potential therapeutic targets for novel intrinsic AKI therapies based on pyroptosis, so as to develop better therapeutic strategies.

Molecular Mechanisms of Cereblon-Interacting Small Molecules in Multiple Myeloma Therapy

Thalidomide analogues (or immunomodulatory imide drugs, IMiDs) are cornerstones in the treatment of multiple myeloma (MM). These drugs bind Cereblon (CRBN), a receptor for the Cullin-ring 4 ubiquitin-ligase (CRL4) complex, to modify its substrate specificity. IMiDs mediate CRBN-dependent engagement and proteasomal degradation of ‘neosubstrates’, Ikaros (IKZF1) and Aiolos (IKZF3), conveying concurrent antimyeloma activity and T-cell costimulation. There is now a greater understanding of physiological CRBN functions, including endogenous substrates and chaperone activity. CRISPR Cas9-based genome-wide screening has further elucidated the complex cellular machinery implicated in IMiD sensitivity, including IKZF1/3-independent mechanisms. New-generation IMiD derivatives with more potent anti-cancer properties—the CELMoDs (Cereblon E3 ligase modulators)—are now being evaluated. Rational drug design also allows ‘hijacking’ of CRL4^CRBN utilising proteolysis targeting chimeras (PROTACs) to convey entirely distinct substrate repertoires. As all these chemotypes—thalidomide, IMiDs, CELMoDs and PROTACs—engage CRBN and modify its functions, we describe them here in aggregate as ‘CRBN-interacting small molecules’ (CISMs). In this review, we provide a contemporary summary of the biological consequences of CRBN modulation by CISMs. Detailed molecular insight into CRBN–CISM interactions now provides an opportunity to more effectively target previously elusive cancer dependencies, representing a new and powerful tool for the implementation of precision medicine.

The use of thalidomide to treat children with tuberculosis meningitis: A review

Much of the morbidity and mortality caused by tuberculous meningitis (TBM) is mediated by a dysregulated immune response. Effective host-directed therapy is therefore critical to improve survival and clinical outcomes. Currently only one host-directed therapy (HDT), corticosteroids, is proven to improve mortality. However, there is no evidence that corticosteroids reduce morbidity and the mechanism of action for mortality reduction is uncertain. Further, it has no proven benefit in HIV co-infected individuals. One promising host-directed therapy approach is to restrict the immunopathology arising from tumour necrosis factor (TNF)-α excess is via TNF-α inhibitors. There are accumulating data on the role of thalidomide, anti-TNF-α monoclonal antibodies (infliximab, adalimumab) and the soluble TNF-α receptor (etanercept) in TBM treatment. Thalidomide was developed nearly seventy years ago and has been a highly controversial drug. Birth defects and toxic adverse effects have limited its use but an improved understanding of its immunological mechanism of action suggest that it may have a crucial role in regulating the destructive host response seen in inflammatory conditions such as TBM. Observational studies at our institution found low dosage adjunctive thalidomide safe in treating tuberculous mass lesions and blindness related to optochiasmatic arachnoiditis, with good clinical and radiological response. In this review, we discuss possible mechanisms of action for thalidomide, based on our clinico-radiologic experience and post-mortem histopathological work. We also propose a rationale for its use in the treatment of certain TBM-related complications.

The Impact of Induction Regimes on Immune Responses in Patients with Multiple Myeloma

Current standard frontline therapy for newly diagnosed patients with multiple myeloma (NDMM) involves induction therapy, autologous stem cell transplantation (ASCT), and maintenance therapy. Major efforts are underway to understand the biological and the clinical impacts of each stage of the treatment protocols on overall survival statistics. The most routinely used drugs in the pre-ASCT "induction" regime have different mechanisms of action and are employed either as monotherapies or in various combinations. Aside from their direct effects on cancer cell mortality, these drugs are also known to have varying effects on immune cell functionality. The question remains as to how induction therapy impacts post-ASCT immune reconstitution and anti-tumor immune responses. This review provides an update on the known immune effects of melphalan, dexamethasone, lenalidomide, and bortezomib commonly used in the induction phase of MM therapy. By analyzing the actions of each individual drug on the immune system, we suggest it might be possible to leverage their effects to rationally devise more effective induction regimes. Given the genetic heterogeneity between myeloma patients, it may also be possible to identify subgroups of patients for whom particular induction drug combinations would be more appropriate.

Thalidomide alleviates neuropathic pain through microglial IL-10/β-endorphin signaling pathway

Thalidomide is an antiinflammatory, antiangiogenic and immunomodulatory agent which has been used for the treatment of erythema nodosum leprosum and multiple myeloma. It has also been employed in treating complex regional pain syndromes. The current study aimed to reveal the molecular mechanisms underlying thalidomide-induced pain antihypersensitive effects in neuropathic pain. Thalidomide gavage, but not its more potent analogs lenalidomide and pomalidomide, inhibited mechanical allodynia and thermal hyperalgesia in neuropathic pain rats induced by tight ligation of spinal nerves, with ED₅₀ values of 44.9 and 23.5 mg/kg, and E_max values of 74% and 84% MPE respectively. Intrathecal injection of thalidomide also inhibited mechanical allodynia and thermal hyperalgesia in neuropathic pain. Treatment with thalidomide, lenalidomide and pomalidomide reduced peripheral nerve injury-induced proinflammatory cytokines (TNFα, IL-1β and IL-6) in the ipsilateral spinal cords of neuropathic rats and LPS-treated primary microglial cells. In contrast, treatment with thalidomide, but not lenalidomide or pomalidomide, stimulated spinal expressions of IL-10 and β-endorphin in neuropathic rats. Particularly, thalidomide specifically stimulated IL-10 and β-endorphin expressions in microglia but not astrocytes or neurons. Furthermore, pretreatment with the IL-10 antibody blocked upregulation of β-endorphin in neuropathic rats and cultured microglial cells, whereas it did not restore thalidomide-induced downregulation of proinflammatory cytokine expression. Importantly, pretreatment with intrathecal injection of the microglial metabolic inhibitor minocycline, IL-10 antibody, β-endorphin antiserum, and preferred or selective μ-opioid receptor antagonist naloxone or CTAP entirely blocked thalidomide gavage-induced mechanical antiallodynia. Our results demonstrate that thalidomide, but not lenalidomide or pomalidomide, alleviates neuropathic pain, which is mediated by upregulation of spinal microglial IL-10/β-endorphin expression, rather than downregulation of TNFα expression.

A unique macrophage subpopulation signals directly to progenitor cells to promote regenerative neurogenesis in the zebrafish spinal cord

Central nervous system injury re-initiates neurogenesis in anamniotes (amphibians and fishes), but not in mammals. Activation of the innate immune system promotes regenerative neurogenesis, but it is fundamentally unknown whether this is indirect through the activation of known developmental signaling pathways or whether immune cells directly signal to progenitor cells using mechanisms that are unique to regeneration. Using single-cell RNA-seq of progenitor cells and macrophages, as well as cell-type-specific manipulations, we provide evidence for a direct signaling axis from specific lesion-activated macrophages to spinal progenitor cells to promote regenerative neurogenesis in zebrafish. Mechanistically, TNFa from pro-regenerative macrophages induces Tnfrsf1a-mediated AP-1 activity in progenitors to increase regeneration-promoting expression of hdac1 and neurogenesis. This establishes the principle that macrophages directly communicate to spinal progenitor cells via non-developmental signals after injury, providing potential targets for future interventions in the regeneration-deficient spinal cord of mammals.

Role of innate immunity in chemotherapy-induced peripheral neuropathy

It has become increasingly clear that the innate immune system plays an essential role in the generation of many types of neuropathic pain including that which accompanies cancer treatment. In this article we review current findings of the role of the innate immune system in contributing to cancer treatment pain at the distal endings of peripheral nerve, in the nerve trunk, in the dorsal root ganglion and in the spinal dorsal horn.

Dysbacteriosis induces abnormal neurogenesis via LPS in a pathway requiring NF-κB/IL-6

In this study, we identified elevated levels of LPS and suppressed neurogenesis in a successfully established mouse model of gut microbiota dysbiosis. We mimicked these phenotypes using mouse and chicken embryos exposed to LPS and found that dramatic variation in gene expression was due to changes in the dorsal-ventral patterning of the neural tube. Cell survival and excess ROS were also involved in this process. Antioxidant administration alleviated LPS-activated NF-κB signaling, while directly blocking NF-κB signaling altered the LPS-induced inhibition of neurogenesis. Furthermore, IL-6 was proven to play a vital role in the expression of crucial neurogenesis-related genes and NF-κB. In summary, we found that the suppression of neurogenesis induced by dysbacteriosis-derived LPS was significantly reversed in mice with fecal microbiota transplantation. This study reveals that gut dysbacteriosis-derived LPS impairs embryonic neurogenesis, and that the NF-κB/IL-6 pathway could be one of the main factors triggering the downstream signaling cascade.

Thalidomide Use for Complicated Central Nervous System Tuberculosis in Children: Insights From an Observational Cohort

BACKGROUND

Much of the neurological sequelae of central nervous system (CNS) tuberculosis (TB) is due to an excessive cytokine-driven host-inflammatory response. Adjunctive corticosteroids, which reduce cytokine production and thus dampen the inflammation, improve overall survival but do not prevent morbidity. This has prompted investigation of more targeted immunomodulatory agents, including thalidomide.

METHODS

We describe a retrospective cohort of 38 children consecutively treated with adjunctive thalidomide for CNS TB-related complications over a 10-year period.

RESULTS

The most common presenting symptom was focal motor deficit (n = 16), followed by cranial nerve palsies and cerebellar dysfunction. Three of the 38 children presented with large dural-based lesions, manifesting as epilepsia partialis continua (EPC), 4 presented with blindness secondary to optochiasmatic arachnoiditis, and 2 children developed paraplegia due to spinal cord TB mass lesions. Duration of adjunctive thalidomide therapy (3-5 mg/kg/day) varied according to complication type. In children compromised by TB mass lesions, the median treatment duration was 3.9 months (interquartile range [IQR], 2.0-5.0 months), whereas in children with optic neuritis it was 2.0 months (IQR, 1.3-7.3 months) and in EPC it was 1.0 months (IQR, 1-2.5 months). Satisfactory clinical and radiological response was observed in 37 of the children. None of the children experienced rashes, hepatitis, or hematologic derangements or complained of leg cramps.

CONCLUSIONS

This study is the largest cohort of adult or pediatric patients treated with adjunctive thalidomide for CNS TB-related complications. The drug has proved to be safe and well tolerated and appears to be clinically efficacious. The potential role of thalidomide or analogues in the treatment of other tuberculous meningitis-related complications requires further exploration.

Tailor-made amino acids in the design of small-molecule blockbuster drugs

The role of amino acids (AAs) in modern health industry is well-appreciated. Residues of individual AAs, or their chemical modifications, such as diamines and amino alcohols, are frequently found in the structures of modern pharmaceuticals. The goal of this review article, is to emphasize that, currently, tailor-made AAs serve as key structural features in many most successful pharmaceuticals, so-called blockbuster drugs. In the present article, we profile 14 small-molecule drugs, underscoring the breadth of structural variety of AAs applications in numerous therapeutic areas. For each compound, we provide spectrum of biological activity, medicinal chemistry discovery, and synthetic approaches.

In pursuit of a selective hepatocellular carcinoma therapeutic agent: Novel thalidomide derivatives with antiproliferative, antimigratory and STAT3 inhibitory properties

Advanced stage liver cancer is predominantly treated with the multi-kinase inhibitor sorafenib; however, this therapeutic agent lacks selectivity in its cytotoxic actions and is associated with poor survival outcomes. Herein we report the design and preparation of several thalidomide derivatives, including a variety of novel thioether-containing forms that are especially rare in the literature. Importantly, two of the derivatives described are potent antiproliferative agents with dose-dependent selectivity for tumorigenic liver progenitor cells (LPC) growth inhibition (up to 36% increase in doubling time at 10 μM) over non-tumorigenic cells (no effect at 10 μM). Furthermore, these putative anti-liver cancer agents were also found to be potent inhibitors of tumorigenic LPC migration. This report also describes these derivatives' effects on several key signalling pathways in our novel liver cell lines by immunofluorescence and AlphaLISA assays. Aryl thioether derivative 7f significantly reduced STAT3 phosphorylation (23%) and its nuclear localisation (16%) at 10 μM in tumorigenic LPCs, implicating the IL-6/JAK/STAT3 axis is central in the mode of action of our derivatives.

Aging-induced IL27Ra signaling impairs hematopoietic stem cells

Hematopoietic stem cell (HSC) aging correlates with an increasing risk of myeloproliferative disease and immunosenescence. In this study, we show that aging-related inflammation promotes HSC aging through tumor necrosis factor-α (TNF-α)→ERK→ETS1→interleukin27Ra (IL27Ra) pathway. TNF-α, a well-known biomarker of inflammation, increases during aging and induces the expression of IL27Ra on HSCs via ERK-ETS1 signaling. Deletion of IL27Ra rescues the functional decline and myeloid bias of HSCs and also reverses the inhibitory effect of TNF-α on HSCs. Aged IL27Ra-/- mice had a reduced proportion of myeloid-biased HSCs and did not display the biased myeloid differentiation that occurs in aged wild-type mice. IL27Ra+ HSCs exhibit impaired reconstitution capacity and myeloid-bias compared with IL27Ra- HSCs and serve as a myeloid-recovery pool upon inflammatory insult. Inflammation-related genes were enriched in IL27Ra+ HSCs and this enrichment increases with aging. Our study demonstrates that age-induced IL27Ra signaling impairs HSCs and raises the possibility that interfering with IL27Ra signaling can counter the physiologically deleterious effect of aging on hematopoietic capacity.

Oxidative DNA Damage, Inflammatory Signature, and Altered Erythrocytes Properties in Diamond-Blackfan Anemia

Molecular pathophysiology of Diamond-Blackfan anemia (DBA) involves disrupted erythroid-lineage proliferation, differentiation and apoptosis; with the activation of p53 considered as a key component. Recently, oxidative stress was proposed to play an important role in DBA pathophysiology as well. CRISPR/Cas9-created Rpl5- and Rps19-deficient murine erythroleukemia (MEL) cells and DBA patients' samples were used to evaluate proinflammatory cytokines, oxidative stress, DNA damage and DNA damage response. We demonstrated that the antioxidant defense capacity of Rp-mutant cells is insufficient to meet the greater reactive oxygen species (ROS) production which leads to oxidative DNA damage, cellular senescence and activation of DNA damage response signaling in the developing erythroblasts and altered characteristics of mature erythrocytes. We also showed that the disturbed balance between ROS formation and antioxidant defense is accompanied by the upregulation of proinflammatory cytokines. Finally, the alterations detected in the membrane of DBA erythrocytes may cause their enhanced recognition and destruction by reticuloendothelial macrophages, especially during infections. We propose that the extent of oxidative stress and the ability to activate antioxidant defense systems may contribute to high heterogeneity of clinical symptoms and response to therapy observed in DBA patients.

Design, synthesis and biological evaluation of thioether-containing lenalidomide and pomalidomide derivatives with anti-multiple myeloma activity

Lenalidomide and its analogs are well-known for treating multiple myeloma. In this work, designed sulfide-modified lenalidomide and pomalidomide were synthesized and evaluated. The anti-proliferative activity against MM.1S cell line of 3ak (IC₅₀ = 79 nM) was similar to lenalidomide (IC₅₀ = 81 nM). Compared to benzylic thioether substituted lenalidomide 3a, the half-live (T_1/2) of 4-F-phenyl-thioether analogs 3ak in human liver microsomes was promoted from 3 min to 416.7 min. The corresponding metabolic factor of 3ak was increased from 2.8% to 79.5%, which was slightly lower than lenalidomide (91.5%). Moreover, the IKZF1 degradation of 3y and 3ak was well related with corresponding IC₅₀ values, which suggested the IKZF1 degradation efficiency is correlated to the responses of MM1. S cells. Furthermore, the oral administration of compounds 3y and 3ak at dosages of 60 mg/kg could delay tumor growth in female CB-17 SCID mice. This research helped to prompt the stability of thioether lenalidomide analogs, which paved the way for developing better molecules for treating multiple myeloma.

Daily alcohol intake triggers aberrant synaptic pruning leading to synapse loss and anxiety-like behavior

Alcohol abuse adversely affects the lives of millions of people worldwide. Deficits in synaptic transmission and in microglial function are commonly found in human alcohol abusers and in animal models of alcohol intoxication. Here, we found that a protocol simulating chronic binge drinking in male mice resulted in aberrant synaptic pruning and substantial loss of excitatory synapses in the prefrontal cortex, which resulted in increased anxiety-like behavior. Mechanistically, alcohol intake increased the engulfment capacity of microglia in a manner dependent on the kinase Src, the subsequent activation of the transcription factor NF-κB, and the consequent production of the proinflammatory cytokine TNF. Pharmacological blockade of Src activation or of TNF production in microglia, genetic ablation of Tnf, or conditional ablation of microglia attenuated aberrant synaptic pruning, thereby preventing the neuronal and behavioral effects of the alcohol. Our data suggest that aberrant pruning of excitatory synapses by microglia may disrupt synaptic transmission in response to alcohol abuse.

The Rationale for Immunotherapy in Myeloproliferative Neoplasms

PURPOSE OF REVIEW

The classic, chronic Philadelphia chromosome negative myeloproliferative neoplasms (MPN)-essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis (MF)-are clonal malignancies of hematopoietic stem cells and are associated with myeloproliferation, organomegaly, and constitutional symptoms. Expanding knowledge that chronic inflammation and a dysregulated immune system are central to the pathogenesis and progression of MPNs serves as a driving force for the development of agents affecting the immune system as therapy for MPN. This review describes the rationale and potential impact of anti-inflammatory, immunomodulatory, and targeted agents in MPNs.

RECENT FINDINGS

The advances in molecular insights, especially the discovery of the Janus kinase 2 (JAK2) V617F mutation and its role in JAK-STAT pathway dysregulation, led to the development of the JAK inhibitor ruxolitinib, which currently represents the cornerstone of medical therapy in MF and hydroxyurea-resistant/intolerant PV. However, there remain significant unmet needs in the treatment of these patients, and many agents continue to be investigated. Novel, more selective JAK inhibitors might offer reduced myelosuppression or even improvement of blood counts. The recent approval of a novel, long-acting interferon for PV patients in Europe, might eventually lead to its broader clinical use in all MPNs. Targeted immunotherapy involving monoclonal antibodies, checkpoint inhibitors, or therapeutic vaccines against selected MPN epitopes could further enhance tumor-specific immune responses. Immunotherapeutic approaches are expanding and hopefully will extend the therapeutic armamentarium in patients with myeloproliferative neoplasms.

TNF-α/HMGB1 inflammation signalling pathway regulates pyroptosis during liver failure and acute kidney injury

OBJECTIVE

Acute kidney injury (AKI) is a common complication of acute liver failure (ALF). Pyroptosis is a necrosis type related to inflammation. This study aimed to investigate the role of TNF-α/HMGB1 pathway in pyroptosis during ALF and AKI.

METHODS

An ALF and AKI mouse model was generated using LPS/D-Gal, and a TNF-α inhibitor, CC-5013, was used to treat the mice. THP-1 cells were induced to differentiate into M1 macrophages, then challenged with either CC-5013 or an HMGB1 inhibitor, glycyrrhizin. pLVX-mCMVZsGreen-PGK-Puros plasmids containing TNF-α wild-type (WT), mutation A94T of TNF-α and mutation P84L of TNF-α were transfected into M1 macrophages.

RESULTS

Treatment with CC-5013 decreased the activation of TNF-α/HMGB1 pathway and pyroptosis in the treated mice and cells compared with the control mice and cells. CC-5013 also ameliorated liver and kidney pathological changes and improved liver and renal functions in treated mice, and the number of M1 macrophages in the liver and kidney tissues also decreased. The activation of TNF-α/HMGB1 pathway and pyroptosis increased in the M1 macrophage group compared with the normal group. Similarly, the activation of TNF-α/HMGB1 pathway and pyroptosis in the LPS + WT group also increased. By contrast, the activation of the TNF-α/HMGB1 pathway and pyroptosis decreased in the LPS + A94T and LPS + P84L groups. Moreover, glycyrrhizin inhibited pyroptosis.

CONCLUSION

The TNF-α/HMGB1 inflammation signalling pathway plays an important role in pyroptosis during ALF and AKI.

Design and synthesis of new lenalidomide analogs via Suzuki cross-coupling reaction

Lenalidomide is a cereblon modulator known for its antitumor, anti-inflammatory, and immunomodulatory properties in clinical applications. Recently, some reported lenalidomide analogs could exhibit a significant bioactivity through various modifications in the isoindolinone ring. In this study, we designed and synthesized a series of novel lenalidomide analogs on the basis of the installation of a methylene chain at the C-4 position of isoindolinone via the Suzuki cross-coupling reaction. These new compounds were further evaluated for their in vitro antiproliferative activities against two tumor cell lines (MM.1S and Mino). Specifically, compound 4c displayed the strongest antiproliferative activity against the MM.1S (IC₅₀  = 0.27 ± 0.03 μM) and Mino (IC₅₀  = 5.65 ± 0.58 μM) tumor cell lines. In summary, we have developed a new synthetic strategy for C-4 derivatization of lenalidomide, providing a bioactive scaffold that could be used to discover further potential antitumor lead compounds in pharmaceutical research.

Pharmacological approaches to mitigate neuroinflammation in Alzheimer's disease

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases characterized by the formation of extracellular amyloid beta (Aβ) plaques and intracellular neurofibrillary tangles (NFTs). Growing evidence suggested that there is an association between neuronal dysfunction and neuroinflammation (NI) in AD, coordinated by the chronic activation of astrocytes and microglial cells along with the subsequent excessive generation of the proinflammatory molecule. Therefore, a better understanding of the relationship between the nervous and immune systems is important in order to delay or avert the neurodegenerative events of AD. The inflammatory/immune pathways and the mechanisms to control these pathways may provide a novel arena to develop new drugs in order to target NI in AD. In this review, we represent the influence of cellular mediators which are involved in the NI process, with regards to the progression of AD. We also discuss the processes and the current status of multiple anti-inflammatory agents which are used in AD and have gone through or going through clinical trials. Moreover, new prospects for targeting NI in the development of AD drugs have also been highlighted.

Ulcerative Colitis in Hematological Malignancies: Paraneoplastic Manifestation or Coincidental Bystander?

Evidence of coexistence of diverse hematological malignancies—lymphoma, leukemia, multiple myeloma, and myelodysplastic syndromes—and either ulcerative colitis or Crohn's disease can be found in the literature. However, a more “systemic” effort to reach further and examine the potential of either one as paraneoplastic manifestation has not been performed. Based on these, three cases of ulcerative colitis manifesting before, simultaneously, and after the onset of different hematological malignancies are presented and critically evaluated.

Thalidomide and Phosphodiesterase 4 Inhibitors as Host Directed Therapeutics for Tuberculous Meningitis: Insights From the Rabbit Model

Tuberculous meningitis (TBM) is the most devastating form of extrapulmonary Mycobacterium tuberculosis infection in humans. Severe inflammation and extensive tissue damage drive the morbidity and mortality of this manifestation of tuberculosis (TB). Antibiotic treatment is ineffective at curing TBM due to variable and incomplete drug penetration across the blood-brain barrier (BBB) and blood-cerebrospinal fluid (CSF) barriers. Adjunctive corticosteroid therapy, used to dampen the inflammation, and the pathologic manifestation of TBM, improves overall survival but does not entirely prevent the morbidity of the disease and has significant toxicities, including immune-suppression. The rabbit has served as a fit for purpose experimental model of human TBM since the early 1900s due to the similarity in the developmental processes of the brain, including neuronal development, myelination, and microglial functions between humans and rabbits. Consistent with the observations made in humans, proinflammatory cytokines, including TNF-α, play a critical role in the pathogenesis of TBM in rabbits focusing the attention on the utility of TNF-α inhibitors in treating the disease. Thalidomide, an inhibitor of monocyte-derived TNF-α, was evaluated in the rabbit model of TBM and shown to improve survival and reduce inflammation of the brain and the meninges. Clinical studies in humans have also shown a beneficial response to thalidomide. However, the teratogenicity and T-cell activation function of the drug limit the use of thalidomide in the clinic. Thus, new drugs with more selective anti-inflammatory properties and a better safety profile are being developed. Some of these candidate drugs, such as phosphodiesterase-4 inhibitors, have been shown to reduce the morbidity and increase the survival of rabbits with TBM. Future studies are needed to assess the beneficial effects of these drugs for their potential to improve the current treatment strategy for TBM in humans.

Molecular mechanisms of thalidomide and its derivatives

Thalidomide, originally developed as a sedative drug, causes multiple defects due to severe teratogenicity, but it has been re-purposed for treating multiple myeloma, and derivatives such as lenalidomide and pomalidomide have been developed for treating blood cancers. Although the molecular mechanisms of thalidomide and its derivatives remained poorly understood until recently, we identified cereblon (CRBN), a primary direct target of thalidomide, using ferrite glycidyl methacrylate (FG) beads. CRBN is a ligand-dependent substrate receptor of the E3 ubiquitin ligase complex cullin-RING ligase 4 (CRL4^CRBN). When a ligand such as thalidomide binds to CRBN, it recognizes various 'neosubstrates' depending on the shape of the ligand. CRL4^CRBN binds many neosubstrates in the presence of various ligands. CRBN has been utilized in a novel protein knockdown technology named proteolysis targeting chimeras (PROTACs). Heterobifunctional molecules such as dBET1 are being developed to specifically degrade proteins of interest. Herein, we review recent advances in CRBN research.

Expression and function of Toll‑like receptors in peripheral blood mononuclear cells in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a common chronic inflammatory autoimmune disease. Toll‑like receptors (TLRs) are involved in non‑specific immunity. In the present study, the roles of TLRs in AS were investigated. The levels of inflammatory cytokines were detected by ELISA and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR). The expression levels of TLRs and nuclear factor‑κB (NF‑κB) signaling‑associated factors were determined via RT‑qPCR and western blot analyses. It was observed that the levels of interleukin (IL)‑6, tumor necrosis factor‑α (TNF‑α), C‑reactive protein, TLR4 and TLR5 were increased in patients with AS, whereas those of IL‑10 and TLR3 were decreased. Pomalidomide, a TNF‑α release inhibitor, reduced the expression of IL‑6, TNF‑α, TLR4, TLR5 and phosphorylated‑p65, and upregulated that of IL‑10, TLR3 and p65 in peripheral blood mononuclear cells from patients with AS. Treatment of patients with infliximab, an anti‑TNF‑α monoclonal antibody, induced similar effects in vivo. In conclusion, it was revealed that inhibition of TNF‑α suppressed inflammatory responses in patients with AS, increased the expression of TLR3 and decreased NF‑κB signaling, and the expression of TLR4 and TLR5. The results indicated that TLRs and the NF‑κB signaling pathway were involved in the regulation of inflammatory responses in AS. These findings provided insight into the mechanisms underlying the development of AS and potential novel therapeutic approaches.