Chloroquine inhibits human CD4+ T-cell activation by AP-1 signaling modulation

Evaluation of the antimalarial and CD4+ T-cell modulatory effects of leaf methanol extract of Phyllanthus muellerianus (Kuntze) Exell (Phyllanthaceae) in Plasmodium berghei-infected mice

ETHNOPHARMACOLOGICAL RELEVANCE

Phyllanthus muellerianus (Kunze) Exell, a member of the Phyllanthaceae family, is a medicinal plant widely distributed in Africa. Decoctions from the leaves are used in Nigeria to treat fevers, convulsions, some neurological disorders and malaria.

AIM OF THE STUDY

This study is to evaluate the anti-malarial properties of methanol extract of Phyllanthus muellerianus (MEPM) leaves and its ethyl acetate fraction using a murine malaria model infected with Plasmodium berghei. Additionally, we seek to investigate the potential modulatory effects of this extract and fraction on CD4+ T-cell populations in the context of malaria infection.

MATERIALS AND METHODS

The anti-malarial effects of the leaf methanol extract of Phyllanthus muellerianus (MEPM) were screened using three established in vivo models of anti-plasmodial screening namely the curative, suppressive and prophylactic models. The methanol extract (MEPM) was afterwards fractionated into hexane (HFPM), ethyl acetate (EAFPM), and methanol (MFPM) fractions. In the pilot anti-malarial screening of the fractions, EAFPM exhibited the best antiparasitic activity. Subsequently, EAFPM was screened for anti-malarial activity using the three models above. The effects of the MEPM and EAFPM on haematological indices (Hb and PCV) of the inoculated animals were further screened and the mean survival time (MST) of the animals was monitored. CD4+ T cells of various groups were counted before and after treatment using a flow cytometer. The EAFPM was further subjected to HPLC analysis for identification of its major compounds.

RESULTS

The EAFPM (100 and 200 mg/kg) elicited 88% and 93% cure respectively in the curative model, while artesunate (5 mg/kg,- the positive control) gave 87% protection. The MEPM and EAFPM also gave significant suppression of parasitemia in the suppressive model. The treated groups survived beyond 28 days as against 11 days by the control group (infected but not treated). The treated groups also prevented anaemia seen in the negative control. The EAFPM group significantly modulated the CD4+ T cell. Compounds identified were Gallocatechin, Quercetin -3-O-gallate, Ellagic acid, and Methylellagic acid rhamnoside).

CONCLUSION

The study established that the leaf of Phyllanthus muellerianus possesses antimalarial activity, thus lending support to its use in the folkloric treatment of malaria.

The multiple roles of autophagy in uveal melanoma and the microenvironment

PURPOSE

Uveal melanoma (UM) is the most common primary malignant intraocular tumor in adults, and effective clinical treatment strategies are still lacking. Autophagy is a lysosome-dependent degradation system that can encapsulate abnormal proteins, damaged organelles. However, dysfunctional autophagy has multiple types and plays a complex role in tumorigenicity depending on many factors, such as tumor stage, microenvironment, signaling pathway activation, and application of autophagic drugs.

METHODS

A systematic review of the literature was conducted to analyze the role of autophagy in UM, as well as describing the development of autophagic drugs and the link between autophagy and the tumor microenvironment.

RESULTS

In this review, we summarize current research advances regarding the types of autophagy, the mechanisms of autophagy, the application of autophagy inhibitors or agonists, autophagy and the tumor microenvironment. Finally, we also discuss the relationship between autophagy and UM.

CONCLUSION

Understanding the molecular mechanisms of how autophagy differentially affects tumor progression may help to design better therapeutic regimens to prevent and treat UM.

Deciphering the immunological interactions: targeting preeclampsia with Hydroxychloroquine's biological mechanisms

Preeclampsia (PE) is a complex pregnancy-related disorder characterized by hypertension, followed by organ dysfunction and uteroplacental abnormalities. It remains a major cause of maternal and neonatal morbidity and mortality worldwide. Although the pathophysiology of PE has not been fully elucidated, a two-stage model has been proposed. In this model, a poorly perfused placenta releases various factors into the maternal circulation during the first stage, including pro-inflammatory cytokines, anti-angiogenic factors, and damage-associated molecular patterns into the maternal circulation. In the second stage, these factors lead to a systemic vascular dysfunction with consecutive clinical maternal and/or fetal manifestations. Despite advances in feto-maternal management, effective prophylactic and therapeutic options for PE are still lacking. Since termination of pregnancy is the only curative therapy, regardless of gestational age, new treatment/prophylactic options are urgently needed. Hydroxychloroquine (HCQ) is mainly used to treat malaria as well as certain autoimmune conditions such as systemic lupus and rheumatoid arthritis. The exact mechanism of action of HCQ is not fully understood, but several mechanisms of action have been proposed based on its pharmacological properties. Interestingly, many of them might counteract the proposed processes involved in the development of PE. Therefore, based on a literature review, we aimed to investigate the interrelated biological processes of HCQ and PE and to identify potential molecular targets in these processes.

Macrophage migration inhibitory factor exacerbates asthmatic airway remodeling via dynamin-related protein 1-mediated autophagy activation

BACKGROUND

Macrophage migration inhibitory factor (MIF) and GTPase dynamin-related protein 1 (Drp1)-dependent aberrant mitochondrial fission are closely linked to the pathogenesis of asthma. However, it is unclear whether Drp1-mediated mitochondrial fission and its downstream targets mediate MIF-induced proliferation of airway smooth muscle cells (ASMCs) in vitro and airway remodeling in chronic asthma models. The present study aims to clarify these issues.

METHODS

In this study, primary cultured ASMCs and ovalbumin (OVA)-induced asthmatic rats were applied. Cell proliferation was detected by CCK-8 and EdU assays. Western blotting was used to detect extracellular signal-regulated kinase (ERK) 1/2, Drp1, autophagy-related markers and E-cadherin protein phosphorylation and expression. Inflammatory cytokines production, airway reactivity test, histological staining and immunohistochemical staining were conducted to evaluate the development of asthma. Transmission electron microscopy was used to observe the mitochondrial ultrastructure.

RESULTS

In primary cultured ASMCs, MIF increased the phosphorylation level of Drp1 at the Ser616 site through activation of the ERK1/2 signaling pathway, which further activated autophagy and reduced E-cadherin expression, ultimately leading to ASMCs proliferation. In OVA-induced asthmatic rats, MIF inhibitor 4-iodo-6-phenylpyrimidine (4-IPP) treatment, suppression of mitochondrial fission by Mdivi-1 or inhibiting autophagy with chloroquine phosphate (CQ) all attenuated the development of airway remodeling.

CONCLUSIONS

The present study provides novel insights that MIF promotes airway remodeling in asthma by activating autophagy and degradation of E-cadherin via ERK/Drp1 signaling pathway, suggesting that targeting MIF/ERK/Drp1 might have potential therapeutic value for the prevention and treatment of asthma.

Immunosuppression by hydroxychloroquine: mechanistic proof in in vitro experiments but limited systemic activity in a randomized placebo-controlled clinical pharmacology study

Based on its wide range of immunosuppressive properties, hydroxychloroquine (HCQ) is used for the treatment of several autoimmune diseases. Limited literature is available on the relationship between HCQ concentration and its immunosuppressive effect. To gain insight in this relationship, we performed in vitro experiments in human PBMCs and explored the effect of HCQ on T and B cell proliferation and Toll-like receptor (TLR)3/TLR7/TLR9/RIG-I-induced cytokine production. In a placebo-controlled clinical study, these same endpoints were evaluated in healthy volunteers that were treated with a cumulative dose of 2400 mg HCQ over 5 days. In vitro, HCQ inhibited TLR responses with IC50s > 100 ng/mL and reaching 100% inhibition. In the clinical study, maximal HCQ plasma concentrations ranged from 75 to 200 ng/mL. No ex vivo HCQ effects were found on RIG-I-mediated cytokine release, but there was significant suppression of TLR7 responses and mild suppression of TLR3 and TLR9 responses. Moreover, HCQ treatment did not affect B cell and T cell proliferation. These investigations show that HCQ has clear immunosuppressive effects on human PBMCs, but the effective concentrations exceed the circulating HCQ concentrations under conventional clinical use. Of note, based on HCQ's physicochemical properties, tissue drug concentrations may be higher, potentially resulting in significant local immunosuppression. This trial is registered in the International Clinical Trials Registry Platform (ICTRP) under study number NL8726.

Study on Hydroxychloroquinine Sulfate Being Given to the Admitted COVID -19 Positive Patients at Institute of JLNMCH, Bhagalpur, Bihar, India

Background

As the global death toll from new coronavirus illness (COVID-19) rises, the scientific community and healthcare systems are under massive pressure to manage the outbreak and develop effective medical remedies. Meanwhile, desperation has pushed practitioners, scientists, and authorities to recommend and attempt medicines with little or no proof. Despite the lack of clear and unequivocal facts supporting its efficacy and safety, hydroxychloroquine-sulfate (HCQS) has recently received substantial public and political interest in treating and prophylaxis new infectious diseases COVID-19.

Aim

To analyze the impact of HCQS in COVID-19-positive patients admitted at tertiary level government-owned Jawaharlal Nehru Medical College and Hospital (JLNMCH, Bhagalpur) Bihar.

Methods

Two hundred two RT-PCR-positive COVID-19 patients were included in this research. The study participants were randomly distributed into the intervention category and control category, each consisting of 101 study subjects. Study participants in the intervention category were administered hydroxychloroquine in 200 mg tablets. The control category was given placebo tablets that looked similar to tablets of hydroxychloroquine and were given in the same pattern. Chest X-ray PA view, 12 lead ECG, baseline hemogram including a concentration of CD4 cells, ratio between the concentration of CD8 cells and CD4 cells and concentration of CD8 cells, the concentration of C-reactive protein, RT PCR test of samples obtained from the oropharyngeal region and nasopharyngeal region nasopharyngeal for verification COVID-19 were done. These measurements were carried out in both the control and intervention categories at baseline and at the moment of obtaining a negative RT-PCR report.

Results

The confirmed cases of COVID-19 was 52.9% in the intervention category and 53.4% in the control category at the end of the administration of drugs. Symptoms related to COVID-19 were observed in 11.6% of subjects in the intervention category and 13.5% in the control category. Other new symptoms were observed in 16.8% of subjects in the intervention category and 14.5% of study subjects in the control category. One death was reported in the control category. Emergency hospitalization was required for one subject in the intervention category, while two subjects in the control category required emergency hospitalization. 12.4 days was the mean duration of recovery in the intervention category, while 13.6 days were the mean duration of recovery in the control category. The recovery duration and COVID-related symptoms were lesser in the intervention category than in the control category; however, the variation between the two categories was statistically non-significant (p˃0.01).

Conclusion

According to this research, no statistically significant difference was noticed in COVID-19 incidence between the control category and intervention category, showing that hydroxychloroquine sulfate cannot be utilized as the main curative agent in the treatment of COVID-19. However, there was a reduction in recovery days and symptoms related to COVID-19 in study subjects administered with HCQS.

Hydroxychloroquine inhibits the mitochondrial antioxidant system in activated T cells

Although hydroxychloroquine (HCQ) has long been used to treat autoimmune diseases, its mechanism of action remains poorly understood. In CD4 T-cells, we found that a clinically relevant concentration of HCQ inhibited the mitochondrial antioxidant system triggered by TCR crosslinking, leading to increased mitochondrial superoxide, impaired activation-induced autophagic flux, and reduced proliferation of CD4 T-cells. In antigen-presenting cells, HCQ also reduced constitutive activation of the endo-lysosomal protease legumain and toll-like receptor 9, thereby reducing cytokine production, but it had little apparent impact on constitutive antigen processing and peptide presentation. HCQ's effects did not require endo-lysosomal pH change, nor impaired autophagosome-lysosome fusion. We explored the clinical relevance of these findings in patients with celiac disease-a prototypic CD4 T-cell-mediated disease-and found that HCQ limits ex vivo antigen-specific T cell responses. We report a T-cell-intrinsic immunomodulatory effect from HCQ and suggest potential re-purposing of HCQ for celiac disease.

Hydroxychloroquine and mortality in COVID-19 patients: a systematic review and a meta-analysis of observational studies and randomized controlled trials

Background: Hydroxychloroquine (HCQ) was proposed as potential treatment for COVID-19, but its association with mortality is unclear. We reviewed published literature for evidence of an association between HCQ (with or without azithromycin (AZM)) and total mortality in COVID-19 patients.Methods: Articles were retrieved until April 29th, 2021 by searching in seven databases. Data were combined using the general-variance-based method.Results: A total of 25 cohort studies (N=41,339 patients) and 11 randomized clinical trials (RCTs; N=8,709) were found. The use of HCQ was not associated with mortality in meta-analysis of RCTs (pooled risk ratio (PRR): 1.08, 95%CI: 0.97-1.20; I2=0%), but it was associated with 20% lower mortality risk (PRR=0.80, 95%CI: 0.69-0.93; I2=80%) in pooling of cohort studies. The negative association with mortality was mainly apparent by pooling cohort studies that used lower doses of HCQ (≤400 mg/day; PRR=0.69, 95%CI: 0.57-0.87). Use of HCQ+AZM (11 studies) was associated with 25% non-statistically significant lower mortality risk (PPR=0.75; 0.51-1.10; P=0.15). Use of HCQ was not associated with severe adverse events (PRR=1.12, 95%CI: 0.88-1.44; I2=0%).Conclusions: HCQ use was not associated with mortality in COVID-19 patients in pooling results from RCTs (high level of certainty of evidence), but it was associated with 20% mortality reduction when findings from observational studies were combined (low level of certainty of evidence). The reduction of mortality was mainly apparent in observational studies where lower doses of HCQ were used. These findings might help disentangling the debate on HCQ use in COVID-19.

Impact of chronic gingivitis management on the cytokine and anti-PPAD expressions in juvenile systemic lupus erythematosus: A six-month follow-up

OBJECTIVE

To evaluate how chronic gingivitis treatment impacts the oral and circulating cytokine expressions after six-month follow-up in patients with juvenile systemic lupus erythematosus (jSLE) and also to evaluate the circulating expression of anti-Porphyromonas gingivalis peptidylarginine deiminase antibodies (anti-PPAD) before and after treatment.

BACKGROUND

Juvenile systemic lupus erythematosus patients present a worse periodontal condition associated with higher gingival crevicular fluid (GCF) levels of interleukin (IL)-1β, IL-8, granulocyte colony-stimulating factor (G-CSF), interferon-γ and monocyte chemoattractant protein (MCP)-1.

MATERIALS AND METHODS

Twenty-one adolescents with jSLE (mean age: 16.2 ± 1.5 years) were recruited. Participants were rheumatologically and periodontally examined. All individuals were clinically diagnosed with gingival inflammation. Chronic gingivitis treatment consisted of supragingival scaling, prophylaxis and oral hygiene instructions. The cytokine levels were determined by bead-based multiplex assays and the anti-PPAD levels by ELISA. Gingival crevicular fluid (GCF) and serum samples were collected at baseline and 6 months after treatment.

RESULTS

We observed a reduction in attachment loss, SLE Disease Activity Index (SLEDAI), IL-1β, IL-10 and MCP-1 GCF levels, and the IL-4 and IL-5 serum levels 6 months after periodontal treatment. On the contrary, a significant increase in GCF expression of IL-4, IL-12, IL-17, IFN-γ and serum levels of anti-PPAD antibody was observed.

CONCLUSION

Juvenile systemic lupus erythematosus patients seem to positively benefit from periodontal treatment by a significantly reduced CAL, a GCF reduction of pro-inflammatory cytokines and an increasing of anti-inflammatory ones. However, an increase in the GCF expression of IL-17 and the serum expression of anti-PPAD antibody 6 months after periodontal treatment might negatively affect the treatment outcome of such patients in the long term.

Segmented intravaginal ring for the combination delivery of hydroxychloroquine and anti-CCR5 siRNA nanoparticles as a potential strategy for preventing HIV infection

Abstract 

Vaginal drug delivery has been shown to be a promising strategy for the prevention of sexually transmitted infections. Therapy delivered at the site of infection has many advantages including improved therapeutic efficacy, reduction in systemic toxicity, and reduced potential for development of drug resistance. We developed a “smart” combination intravaginal ring (IVR) that will (1) provide continuous release of hydroxychloroquine (HCQ) to induce T cell immune quiescence as the first-line of defense and (2) release nanoparticles containing anti-CCR5 siRNA only during sexual intercourse when triggered by the presence of seminal fluid as the second-line of defense. The IVR was capable of releasing HCQ over 25 days with a mean daily release of 31.17 ± 3.06 µg/mL. In the presence of vaginal fluid simulant plus seminal fluid simulant, over 12 × more nanoparticles (5.12 ± 0.9 mg) were released over a 4-h period in comparison to IVR segments that were incubated in the presence of vaginal fluid simulant alone (0.42 ± 0.19 mg). Anti-CCR5 siRNA nanoparticles were able to knockdown 83 ± 5.1% of CCR5 gene expression in vitro in the CD4⁺ T cell line Sup-T1. The IVR system also demonstrated to be non-cytotoxic to VK2/E6E7 vaginal epithelial cells.

Graphical abstract

The PI3K∂-Selective Inhibitor Idelalisib Induces T- and NK-Cell Dysfunction Independently of B-Cell Malignancy-Associated Immunosuppression

B-cell receptors, multiple receptor tyrosine kinases, and downstream effectors are constitutively active in chronic lymphocytic leukemia (CLL) B cells. Activation of these pathways results in resistance to apoptosis and enhanced survival of the leukemic cells. Idelalisib is a highly selective inhibitor of the PI3K p110∂ isoform and is approved for the treatment of CLL in patients with relapsed/refractory disease or in those harboring 17p deletions or tp53 mutations. Despite the initial excitement centered around high response rates in clinical trials of idelalisib, its therapeutic success has been hindered by the incidence of severe opportunistic infections. To examine the potential contribution of idelalisib to the increased risk of infection, we investigated the effects of idelalisib on the immune cell compartments of healthy donors (HDs) and CLL patients. PI3K∂ blockade by idelalisib reduced the expression levels of inhibitory checkpoint molecules in T cells isolated from both HDs and CLL patients. In addition, the presence of idelalisib in cultures significantly decreased T-cell-mediated cytotoxicity and granzyme B secretion, as well as cytokine secretion levels in both cohorts. Furthermore, idelalisib reduced the proliferation and cytotoxicity of HD NK cells. Collectively, our data demonstrate that both human T and NK cells are highly sensitive to PI3K∂ inhibition. Idelalisib interfered with the functions of T and NK cell cells from both HDs and CLL patients. Therefore, idelalisib might contribute to an increased risk of infections regardless of the underlying B-cell malignancy.

Hydroxychloroquine Effects on TLR Signalling: Underexposed but Unneglectable in COVID-19

The main basis for hydroxychloroquine (HCQ) treatment in COVID-19 is the compound's ability to inhibit viral replication in vitro. HCQ also suppresses immunity, mainly by interference in TLR signalling, but reliable clinical data on the extent and nature of HCQ-induced immunosuppression are lacking. Here, we discuss the mechanistic basis for the use of HCQ against SARS-CoV-2 in a prophylactic setting and in a therapeutic setting, at different stages of the disease. We argue that the clinical effect of prophylactic or therapeutic HCQ treatment in COVID-19 depends on the balance between inhibition of viral replication, immunosuppression, and off-target side effects, and that the outcome is probably dependent on disease stage and disease severity. This is supported by the initial outcomes of the well-designed randomized controlled trials: so far, evidence for a beneficial effect of HCQ treatment for COVID-19 is weak and conflicting.

Packed red blood cells inhibit T-cell activation via ROS-dependent signaling pathways

Numerous observations indicate that red blood cells (RBCs) affect T-cell activation and proliferation. We have studied effects of packed RBCs (PRBCs) on T-cell receptor (TCR) signaling and the molecular mechanisms whereby (P)RBCs modulate T-cell activation. In line with previous reports, PRBCs attenuated the expression of T-cell activation markers CD25 and CD69 upon costimulation via CD3/CD28. In addition, T-cell proliferation and cytokine expression were markedly reduced when T-cells were stimulated in the presence of PRBCs. Inhibitory activity of PRBCs required direct cell–cell contact and intact PRBCs. The production of activation-induced cellular reactive oxygen species, which act as second messengers in T-cells, was completely abrogated to levels of unstimulated T-cells in the presence of PRBCs. Phosphorylation of the TCR-related zeta chain and thus proximal TCR signal transduction was unaffected by PRBCs, ruling out mechanisms based on secreted factors and steric interaction restrictions. In large part, downstream signaling events requiring reactive oxygen species for full functionality were affected, as confirmed by an untargeted MS-based phosphoproteomics approach. PRBCs inhibited T-cell activation more efficiently than treatment with 1 mM of the antioxidant N-acetyl cysteine. Taken together, our data imply that inflammation-related radical reactions are modulated by PRBCs. These immunomodulating effects may be responsible for clinical observations associated with transfusion of PRBCs.

Superoxide Dismutase 3 Controls the Activation and Differentiation of CD4+T Cells

Superoxide dismutase 3 (SOD3), a well-known antioxidant has been shown to possess immunomodulatory properties through inhibition of T cell differentiation. However, the underlying inhibitory mechanism of SOD3 on T cell differentiation is not well understood. In this study, we investigated the effect of SOD3 on anti-CD3/CD28- or phorbol myristate acetate (PMA) and ionomycin (ION)-mediated activation of mouse naive CD4⁺ T cells. Our data showed that SOD3 suppressed the expression of activation-induced surface receptor proteins such as CD25, and CD69, and cytokines production. Similarly, SOD3 was found to reduce CD4⁺T cells proliferation and suppress the activation of downstream pathways such as ERK, p38, and NF-κB. Moreover, naïve CD4⁺T cells isolated from global SOD3 knock-out mice showed higher expression of CD25, CD69, and CD71, IL-2 production, proliferation, and downstream signals compared to wild-type CD4⁺T cells. Whereas, the use of DETCA, a known inhibitor of SOD3 activity, found to nullify the inhibitory effect of SOD3 on CD4⁺T cell activation of both SOD3 KO and wild-type mice. Furthermore, the expression of surface receptor proteins, IL-2 production, and downstream signals were also reduced in Th2 and Th17 differentiated cells upon SOD3 treatment. Overall, our data showed that SOD3 can attenuate CD4⁺T cell activation through modulation of the downstream signalings and restrict CD4⁺T cell differentiation. Therefore, SOD3 can be a promising therapeutic for T cell-mediated disorders.

Drug Discovery by Drug Repurposing: Combating COVID-19 in the 21st Century

Due to the rapidly developing nature of the current COVID-19 outbreak and its almost immediate humanitarian and economic toll, coronavirus drug discovery efforts have largely focused on generating potential COVID-19 drug candidates as quickly as possible. Globally, scientists are working day and night to find the best possible solution to treat the deadly virus. During the first few months of 2020, the SARS-CoV-2 outbreak quickly developed into a pandemic, with a mortality rate that was increasing at an exponential rate day by day. As a result, scientists have turned to a drug repurposing approach to rediscover the potential use and benefits of existing approved drugs. Currently, there is no single drug approved by the U.S. Food and Drug Administration (FDA), for the treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, previously known as 2019-nCoV) that causes COVID-19. Based on only in-vitro studies, several active drugs are already in the clinical pipeline, made possible by following the compassionate use of medical protocols. This method of repurposing and the use of existing molecules like Remdesivir (GS-5734), Chloroquine, Hydroxychloroquine, etc. has proven to be a landmark in the field of drug rediscovery. In this review article, we will discuss the repurposing of medicines for treating the deadly novel coronavirus (SARS-CoV-2).

Reviews on Biological Activity, Clinical Trial and Synthesis Progress of Small Molecules for the Treatment of COVID-19

COVID-19 has broken out rapidly in nearly all countries worldwide, and has blossomed into a pandemic. Since the beginning of the spread of COVID-19, many scientists have been cooperating to study a vast array of old drugs and new clinical trial drugs to discover potent drugs with anti-COVID-19 activity, including antiviral drugs, antimalarial drugs, immunosuppressants, Chinese medicines, Mpro inhibitors, JAK inhibitors, etc. The most commonly used drugs are antiviral compounds, antimalarial drugs and JAK inhibitors. In this review, we summarize mainly the antimalarial drugs chloroquine and hydroxychloroquine, the antiviral drugs Favipiravir and Remdesivir, and JAK inhibitor Ruxolitinib, discussing their biological activities, clinical trials and synthesis progress.

Hydroxychloroquine can impair tumor response to anti-PD1 in subcutaneous mouse models

Hydroxychloroquine (HCQ) is a well-known anti-inflammatory drug but is also known as an anti-inflammatory drug. Here, we evaluate the influence of HCQ treatment on the effect of anti-PD1 tumor immunotherapy. Anti-PD1 therapy-sensitive tumor lines MC38, CT26, and RIL-175 were used to investigate the impact of HCQ on anti-PD1 therapy efficacy. In vitro assays demonstrated that HCQ directly inhibited tumor cell growth in all the tested tumor cell lines. HCQ treatment impaired both antigen-specific and nonspecific T-cell production of TNFα and IFNγ in vitro and in vivo. Importantly, in all the three tumor models, HCQ treatment significantly impaired the response to anti-PD1 treatment, accompanying diminished in vivo T-cell activation and reduced tumor-infiltrating, antigen-specific CD8⁺ T cells. This study shows that HCQ treatment can result in immunotherapy failure due to its immunosuppressive effects that offset both increased MHC-I expression by tumor cell and direct cytotoxicity.

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HCQ inhibits both antigen-specific and nonspecific CD4⁺ and CD8⁺ T function

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HCQ inhibits tumor cell growth in vitro

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HCQ impairs anti-PD1 therapy

An overview on the use of antivirals for the treatment of patients with COVID19 disease

Introduction: There is an urgent need for safe and efficacious antiviral drugs to improve outcomes for COVID-19 patients. Understanding SARS-CoV-2 virology can elucidate potential drug targets for the inhibition of viral replication. Areas covered: This review offers insights into novel and repurposed drugs that may have activity against SARS-CoV-2. We searched the PubMed, Medline, Google Scholar, Web of Science and ClinicalTrials.gov for COVID-19 related therapy until 28 October 2020. using search words 'SARS-CoV-2', 'COVID-19', 'antiviral', and/or 'treatment'. Expert opinion: Remdesivir decreased symptom duration modestly but had no significant impact on survival. Antivirals alone may be insufficient for a specific subset of patients with severe disease because of cytokine release syndrome (CRS). Treatment may require a combination of antivirals and immunomodulators to inhibit viral replication and CRS, respectively. A safe and efficacious SARS-CoV-2 specific vaccine is critical for prevention and mortality reduction. Moreover, we cannot overstate the importance of randomized controlled trials (RCTs) in testing of novel treatments. The pervasive stumbling block, however, is the low representation of minority groups. The benefit of remdesivir may not be generalizable to these populations because of significant underrepresentation in trials. Future endeavors should encompass the recruitment of patient populations that are reflective of the demographics significantly impacted by COVID-19.

T Cells in Autoimmunity-Associated Cardiovascular Diseases

T cells are indisputably critical mediators of atherosclerotic cardiovascular disease (CVD), where they secrete pro-inflammatory cytokines that promote vascular pathology. Equally well-established is the fact that autoimmune diseases, which are mediated by autoreactive T cells, substantially increase the risk of developing CVD. Indeed, as immunomodulatory treatments have become more effective at treating end-organ pathology, CVD has become a leading cause of death in patients with autoimmune diseases. Despite this, investigators have only recently begun to probe the mechanisms by which autoreactive T cells promote CVD in the context of autoimmune diseases. T cells are best-studied in the pathogenesis of systemic vasculitides, where they react to self-antigen in the vessel wall. However, newer studies indicate that T cells also contribute to the increased CVD risk associated with lupus and rheumatoid arthritis. Given the central role of T-cell-derived cytokines in the pathogenesis of psoriasis, the role of these factors in psoriatic CVD is also under investigation. In the future, T cells are likely to represent major targets for the prevention and treatment of CVD in patients with autoimmune diseases.

Immune Modulation as a Therapeutic Option During the SARS-CoV-2 Outbreak: The Case for Antimalarial Aminoquinolines

The rapid spread, severity, and lack of specific treatment for COVID-19 resulted in hasty drug repurposing. Conceptually, trials of antivirals were well-accepted, but twentieth century antimalarials sparked an impassioned global debate. Notwithstanding, antiviral and immunomodulatory effects of aminoquinolines have been investigated in vitro, in vivo and in clinical trials for more than 30 years. We review the mechanisms of action of (hydroxy)chloroquine on immune cells and networks and discuss promises and pitfalls in the fight against SARS-CoV-2, the agent of the COVID-19 outbreak.

The host targeting effect of chloroquine in malaria

Due to the rapid onset and spread of the COVID-19 pandemic, the treatment of COVID-19 patients by hydroxychloroquine alone or in combination with other drugs has captured a great deal of attention and triggered considerable debate. Historically, the worldwide use of quinoline based-drugs has led to a spectacular reduction in death from malaria. Unfortunately, scientists have been forced to seek alternative drugs to treat malaria due to the emergence of chloroquine-resistant parasites in the 1960s. The repurposing of hydroxychloroquine against viral infections, various types of cancer and autoimmune diseases has been ongoing for more than 70 years, with no clear understanding of its mechanism of action (MOA). Here, we closely examine the MOA of this old but influential drug in and beyond malaria. Better insights into how chloroquine targets the host's cellular and immune responses may help to develop applications against to new pathogens and diseases, and perhaps even restore the clinical utility of chloroquine against malaria.

A systematic review on use of aminoquinolines for the therapeutic management of COVID-19: Efficacy, safety and clinical trials

Recent global outbreak of the pandemic caused by coronavirus (COVID-19) emphasizes the urgent need for novel antiviral therapeutics. It can be supplemented by utilization of efficient and validated drug discovery approaches such as drug repurposing/repositioning. The well reported and clinically used anti-malarial aminoquinoline drugs (chloroquine and hydroxychloroquine) have shown potential to be repurposed to control the present pandemic by inhibition of COVID-19. The review elaborates the mechanism of action, safety (side effects, adverse effects, toxicity) and details of clinical trials for chloroquine and hydroxychloroquine to benefit the clinicians, medicinal chemist, pharmacologist actively involved in controlling the pandemic and to provide therapeutics for the treatment of COVID-19 infection.

Cellular and Molecular Pathways of COVID-19 and Potential Points of Therapeutic Intervention

With the objective of linking early findings relating to the novel SARS-CoV-2 coronavirus with potentially informative findings from prior research literature and to promote investigation toward therapeutic response, a coherent cellular and molecular pathway is proposed for COVID-19. The pathway is consistent with a broad range of observed clinical features and biological markers and captures key mediators of pathophysiology. In this proposed pathway, membrane fusion and cytoplasmic entry of SARS-CoV-2 virus via ACE2 and TMPRSS2-expressing respiratory epithelial cells, including pulmonary type-II pneumocytes, provoke an initial immune response featuring inflammatory cytokine production coupled with a weak interferon response, particularly in IFN-λ-dependent epithelial defense. Differentiation of non-classic pathogenic T-cells and pro-inflammatory intermediate monocytes contributes to a skewed inflammatory profile, mediated by membrane-bound immune receptor subtypes (e.g., FcγRIIA) and downstream signaling pathways (e.g., NF-κB p65 and p38 MAPK), followed by chemotactic infiltration of monocyte-derived macrophages and neutrophils into lung tissue. Endothelial barrier degradation and capillary leakage contribute to alveolar cell damage. Inflammatory cytokine release, delayed neutrophil apoptosis, and NETosis contribute to pulmonary thrombosis and cytokine storm. These mechanisms are concordant with observed clinical markers in COVID-19, including high expression of inflammatory cytokines on the TNF-α/IL-6 axis, elevated neutrophil-to-lymphocyte ratio (NLR), diffuse alveolar damage via cell apoptosis in respiratory epithelia and vascular endothelia, elevated lactate dehydrogenase (LDH) and CRP, high production of neutrophil extracellular traps (NETs), depressed platelet count, and thrombosis. Although certain elements are likely to be revised as new findings emerge, the proposed pathway suggests multiple points of investigation for potential therapeutic interventions. Initial candidate interventions include prophylaxis to augment epithelial defense (e.g., AT1 receptor blockade, type III and type I interferons, melatonin, calcitriol, camostat, and lopinavir) and to reduce viral load (e.g., remdesivir, ivermectin, emetine, Abelson kinase inhibitors, dopamine D2 antagonists, and selective estrogen receptor modulators). Additional interventions focus on tempering inflammatory signaling and injury (e.g., dexamethasone, doxycycline, Ang1-7, estradiol, alpha blockers, and DHA/EPA, pasireotide), as well as inhibitors targeted toward molecular mediators of the maladaptive COVID-19 immune response (e.g., IL-6, TNF-α, IL-17, JAK, and CDK9).

Hydroxychloroquine in rheumatic autoimmune disorders and beyond

Initially used as antimalarial drugs, hydroxychloroquine (HCQ) and, to a lesser extent, chloroquine (CQ) are currently being used to treat several diseases. Due to its cost‐effectiveness, safety and efficacy, HCQ is especially used in rheumatic autoimmune disorders (RADs), such as systemic lupus erythematosus, primary Sjögren's syndrome and rheumatoid arthritis. Despite this widespread use in the clinic, HCQ molecular modes of action are still not completely understood. By influencing several cellular pathways through different mechanisms, CQ and HCQ inhibit multiple endolysosomal functions, including autophagy, as well as endosomal Toll‐like receptor activation and calcium signalling. These effects alter several aspects of the immune system with the synergistic consequence of reducing pro‐inflammatory cytokine production and release, one of the most marked symptoms of RADs. Here, we review the current knowledge on the molecular modes of action of these drugs and the circumstances under which they trigger side effects. This is of particular importance as the therapeutic use of HCQ is expanding beyond the treatment of malaria and RADs.

Chloroquine as a promising adjuvant therapy for type 1 Diabetes Mellitus

Chloroquine (CQ) and hydroxychloroquine, are promising anti-inflammatory drugs for the treatment of Diabetes mellitus (DM) to prevent associated complications. Therefore, this study evaluated the anti-inflammatory effects of CQ-free and CQ-incorporated polylactic acid nanoparticles (NPs) in the peripheral blood mononuclear cells (PBMCs) of patients with type 1 Diabetes mellitus (T1DM). In total, 25 normoglycemic individuals and 25 patients with T1DM aged 10-16 years were selected and glycemic controls evaluated. After cell viability assessed by MTT assay, T1DM PBMCs were subjected to a CQ concentration of 10 µM in three different conditions: not treated (NT), treated with CQ, and treated with CQ NPs. The cells were incubated for 48 h, and the mRNA expressions of cytokines IL1B, IFNG, TNFA, IL12, and IL10 were determined by relative quantification through real-time PCR at 24 h intervals. IL1B expression decreased in CQ and CQ NP-treated cells after 48 h (p < 0.001) and 24 h (p < 0.05) of treatment, respectively. IFNG and IL12 expressions significantly decreased (p < 0.001) in cells treated with CQ and CQ NPs at 24 and 48 h compared to NT. TNFA and IL10 expressions significantly decreased after 48 h (p < 0.001) and 24 h (p < 0.002), respectively, by both CQ and CQ NPs treatment. Despite being a preliminary in vitro study, CQ has anti-inflammatory activity in the primary cells of T1DM patients and could represent an alternative and adjuvant anti-inflammatory therapy to prevent diabetes complications.

Immunomodulatory Effects of Hydroxychloroquine and Chloroquine in Viral Infections and Their Potential Application in Retinal Gene Therapy

Effective treatment of retinal diseases with adeno-associated virus (AAV)-mediated gene therapy is highly dependent on the proportion of successfully transduced cells. However, due to inflammatory reactions at high vector doses, adjunctive treatment may be necessary to enhance the therapeutic outcome. Hydroxychloroquine and chloroquine are anti-malarial drugs that have been successfully used in the treatment of autoimmune diseases. Evidence suggests that at high concentrations, hydroxychloroquine and chloroquine can impact viral infection and replication by increasing endosomal and lysosomal pH. This effect has led to investigations into the potential benefits of these drugs in the treatment of viral infections, including human immunodeficiency virus and severe acute respiratory syndrome coronavirus-2. However, at lower concentrations, hydroxychloroquine and chloroquine appear to exert immunomodulatory effects by inhibiting nucleic acid sensors, including toll-like receptor 9 and cyclic GMP-AMP synthase. This dose-dependent effect on their mechanism of action supports observations of increased viral infections associated with lower drug doses. In this review, we explore the immunomodulatory activity of hydroxychloroquine and chloroquine, their impact on viral infections, and their potential to improve the efficacy and safety of retinal gene therapy by reducing AAV-induced immune responses. The safety and practicalities of delivering hydroxychloroquine into the retina will also be discussed.

COVID-19 as an Acute Inflammatory Disease

The 2019 coronavirus disease (COVID-19) pandemic caused by the virus severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has created an unprecedented global crisis for the infrastructure sectors, including economic, political, healthcare, education, and research systems. Although over 90% of infected individuals are asymptomatic or manifest noncritical symptoms and will recover from the infection, those individuals presenting with critical symptoms are in urgent need of effective treatment options. Emerging data related to mechanism of severity and potential therapies for patients presenting with severe symptoms are scattered and therefore require a comprehensive analysis to focus research on developing effective therapeutics. A critical literature review suggests that the severity of SARS-CoV-2 infection is associated with dysregulation of inflammatory immune responses, which in turn inhibits the development of protective immunity to the infection. Therefore, the use of therapeutics that modulate inflammation without compromising the adaptive immune response could be the most effective therapeutic strategy.

Chloroquine Treatment Suppresses Mucosal Inflammation in a Mouse Model of Eosinophilic Chronic Rhinosinusitis

PURPOSE

The Toll-like receptor 9 (TLR9) signaling pathway is involved in the pathogenesis of chronic rhinosinusitis (CRS) with nasal polyposis. The aim of this study was to assess the therapeutic potential of the TLR9 pathway inhibitor chloroquine in CRS mice.

METHODS

The expression of type I interferons (IFNs) in human CRS tissues was evaluated using quantitative polymerase chain reaction (qPCR), western blotting, and immunofluorescence. Mice were divided into 4 treatment groups: the control, nasal polyp (NP), chloroquine treatment (NP + Chlq), and dexamethasone treatment (NP + Dexa) groups. The effects of chloroquine on polyp formation and mucosal inflammation were examined by hematoxylin and eosin staining. The expression levels of type I IFN, B-cell activating factor (BAFF), TLR9, high mobility group box 1 (HMGB1), and proinflammatory cytokine expression levels were assessed using qPCR, western blot, or enzyme-linked immunosorbent assay.

RESULTS

IFN-α and IFN-β mRNA levels were significantly higher in patients with eosinophilic NPs (EPs) than in healthy individuals or non-EP patients. The polyp score, epithelial thickness, mucosal thickness, and the number of eosinophils in nasal mucosa were significantly higher in the NP group compared with the control, NP + Chlq, and NP + Dexa groups. NP + Chlq or NP + Dexa significantly suppressed the induction of type I IFN and BAFF expression in the NP group; these treatments also significantly suppressed the induction of TLR9, HMGB1, interferon regulatory factors, interleukin (IL)-6, IL-1β, tumor necrosis factor-α, and Th cytokine expression in the NP group. The secreted levels of anti-dsDNA Immunoglobulin G (IgG) were significantly higher in the NP group than in the control, NP + Chlq, and NP + Dexa groups. There were significant positive correlations between BAFF and mRNA levels of IFN-α/β/the protein levels of anti-dsDNA IgG.

CONCLUSIONS

Chloroquine may be used for the treatment of patients with eosinophilic CRS.

Chloroquine modulates inflammatory autoimmune responses through Nurr1 in autoimmune diseases

For over a half-century the anti-malarial drug chloroquine (CQ) has been used as a therapeutic agent, alone or in combination, to treat autoimmune diseases. However, neither the underlying mechanism(s) of action nor their molecular target(s) are well defined. The orphan nuclear receptor Nurr1 (also known as NR4A2) is an essential transcription factor affecting the development and maintenance of midbrain dopaminergic neurons. In this study, using in vitro T cell differentiation models, we demonstrate that CQ activates T_REG cell differentiation and induces Foxp3 gene expression in a Nurr1-dependent manner. Remarkably, CQ appears to induce Nurr1 function by two distinct mechanisms: firstly, by direct binding to Nurr1’s ligand-binding domain and promoting its transcriptional activity and secondly by upregulation of Nurr1 expression through the CREB signaling pathway. In contrast, CQ suppressed gene expression and differentiation of pathogenic T_H17 cells. Importantly, using a valid animal model of inflammatory bowel disease (IBD), we demonstrated that CQ promotes Foxp3 expression and differentiation of T_REG cells in a Nurr1-dependent manner, leading to significant improvement of IBD-related symptoms. Taken together, these data suggest that CQ ameliorates autoimmune diseases via regulating Nurr1 function/expression and that Nurr1 is a promising target for developing effective therapeutics of human inflammatory autoimmune diseases.

Autophagy inhibition enhances PD-L1 expression in gastric cancer

Background

Autophagy, a process for degrading intracellular substances to maintain basal metabolic turnover, is known to be perturbed in gastric cancer. Programmed cell death-1 (PD-1) with its ligand (PD-L1) are important immune checkpoint proteins and their regulation by autophagy has been reported in mouse melanoma and human ovarian cancer. Here, we explored the interplay between autophagy and the PD1/PD-L1 axis in gastric cancer.

Methods

The expression of PD-L1 in gastric cancer cells was detected by Western blot and flow cytometry analysis. The effect of autophagy inhibition on PD-L1 expression was examined in vitro and in vivo. The molecular mechanisms of the regulation of PD-L1 by autophagy were evaluated in gastric cancer cell lines. The clinical relevance of autophagy-related markers p62/SQSTM1 and LC3 with PD-L1 was evaluated in 137 patients with gastric cancer.

Results

We found that inhibition of autophagy by pharmacological inhibitors or small interfering RNAs increased the levels of PD-L1 in cultured gastric cancer cells and in xenografts. Interferon (IFN)-γ also promoted PD-L1 gene transcription, whose action was enhanced by autophagy inhibition. Mechanistically, autophagy inhibition led to the accumulation of p62/SQSTM1 and activation of nuclear factor (NF)-κB, in which NF-κB inhibition or p62/SQSTM1 knockdown attenuated PD-L1 induction by autophagy inhibition. Immunohistochemical staining of primary tumor tissues of 137 patients with gastric cancer showed that LC3 and p62/SQSTM1 protein levels were positively correlated with PD-L1 (LC3, p < 0.001; p62/SQSTM1, p < 0.05). The expression of PD-L1 was also positively correlated with tumor lymphocyte infiltration (p < 0.001).

Conclusions

We discovered that autophagy regulates PD-L1 expression in gastric cancer through the p62/SQSTM1-NF-κB pathway. Pharmacological modulation of autophagy may thus influence the therapeutic efficacy of PD-L1 blockade in gastric cancer.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1148-5) contains supplementary material, which is available to authorized users.

Autophagy in endothelial cells and tumor angiogenesis

In mammalian cells, autophagy is the major pathway for the degradation and recycling of obsolete and potentially noxious cytoplasmic materials, including proteins, lipids, and whole organelles, through the lysosomes. Autophagy maintains cellular and tissue homeostasis and provides a mechanism to adapt to extracellular cues and metabolic stressors. Emerging evidence unravels a critical function of autophagy in endothelial cells (ECs), the major components of the blood vasculature, which delivers nutrients and oxygen to the parenchymal tissue. EC-intrinsic autophagy modulates the response of ECs to various metabolic stressors and has a fundamental role in redox homeostasis and EC plasticity. In recent years moreover, genetic evidence suggests that autophagy regulates pathological angiogenesis, a hallmark of solid tumors. In the hypoxic, nutrient-deprived, and pro-angiogenic tumor microenvironment, heightened autophagy in the blood vessels is emerging as a critical mechanism enabling ECs to dynamically accommodate their higher bioenergetics demands to the extracellular environment and connect with other components of the tumor stroma through paracrine signaling. In this review, we provide an overview of the major cellular mechanisms regulated by autophagy in ECs and discuss their potential role in tumor angiogenesis, tumor growth, and response to anticancer therapy.

Vascular homeostasis relies on the proper behavior of endothelial cells (ECs). Emerging evidence indicate a critical role of autophagy, a vesicular process for lysosomal degradation of cytoplasmic content, in EC biology. While EC-intrinsic autophagy promotes EC function and quiescent state through redox homeostasis and possibly metabolic control, a role for EC-associated autophagy in cancer seems more complex.

The multifaceted role of autophagy in cancer and the microenvironment

Autophagy is a crucial recycling process that is increasingly being recognized as an important factor in cancer initiation, cancer (stem) cell maintenance as well as the development of resistance to cancer therapy in both solid and hematological malignancies. Furthermore, it is being recognized that autophagy also plays a crucial and sometimes opposing role in the complex cancer microenvironment. For instance, autophagy in stromal cells such as fibroblasts contributes to tumorigenesis by generating and supplying nutrients to cancerous cells. Reversely, autophagy in immune cells appears to contribute to tumor‐localized immune responses and among others regulates antigen presentation to and by immune cells. Autophagy also directly regulates T and natural killer cell activity and is required for mounting T‐cell memory responses. Thus, within the tumor microenvironment autophagy has a multifaceted role that, depending on the context, may help drive tumorigenesis or may help to support anticancer immune responses. This multifaceted role should be taken into account when designing autophagy‐based cancer therapeutics. In this review, we provide an overview of the diverse facets of autophagy in cancer cells and nonmalignant cells in the cancer microenvironment. Second, we will attempt to integrate and provide a unified view of how these various aspects can be therapeutically exploited for cancer therapy.

Hydroxychloroquine Inhibits the Differentiation of Th17 Cells in Systemic Lupus Erythematosus

Objective.

Hydroxychloroquine (HCQ) is a commonly used medicine for the treatment of systemic lupus erythematosus (SLE), and Th17 cells are closely related to the pathogenesis of SLE. However, the role and mechanism of HCQ on Th17 cell differentiation in SLE is not clearly understood. Here, we investigate the effect of HCQ on Th17 cell differentiation bothin vitroand in patients with SLE.

Methods.

Twenty-five patients with SLE were divided into 2 treatment groups: prednisone alone and HCQ plus prednisone. Interleukin 17 (IL-17) expression was analyzed by ELISA and real-time (RT)-PCR. Th17 were measured in patients with SLE by flow cytometry before and after HCQ treatment.In vitro, naive T cells were cultured in Th17-inducing conditions with or without HCQ. Cell differentiation and IL-17 expression were analyzed. Finally, transcriptome sequencing identified differential gene expression between naive T cells and induced Th17 cells.

Results.

In patients, HCQ plus prednisone treatment inhibited IL-17 production, gene expression, and Th17 cell differentiation.In vitro, HCQ inhibited Th17 cell proliferation and differentiation, as well as IL-17 production. Five microRNA were significantly different in Th17 cells compared with naive T cells, and HCQ treatment reversed this effect.In vivo, microRNA-590 (miR-590) was verified and was significantly decreased in Th17 cells, compared with naive T cells from lupus-prone mice. Moreover, miR-590 was increased in patients treated with HCQ plus prednisone.

Conclusion.

HCQ inhibited Th17 cell differentiation and IL-17 production bothin vitroand in patients with SLE. Our study provides additional evidence for HCQ as a treatment for SLE.