Impact of latency-reversing agents on human macrophage physiology

INTRODUCTION

HIV-1 eradication is hindered by the presence of inducible long-lived reservoirs of latently infected cells which rapidly disseminate viral particles upon treatment interruption. Eliminating these reservoirs by the so-called shock and kill strategy represents a crucial concept toward an HIV-1 cure. Several molecules called latency-reversing agents (LRAs) are under intensive investigations to reactivate virus gene expression. These studies are mainly conducted on CD4⁺ T cells where LRAs are well tolerated and did not induce global cellular activation. However, despite their broad spectrum, the putative impact of LRAs on other cellular reservoirs such as macrophages is still ill-defined.

METHODS

We investigated the impact of the protein kinase C (PKC) activator bryostatin-1, bromodomain inhibitor JQ1 and histone deacetylase inhibitor romidepsin used either alone or in combination on human primary monocyte-derived macrophages (MDMs).

RESULTS

We demonstrate that bryostatin-1, JQ1, and romidepsin or their combinations are not toxic at nanomolar concentrations but induce metabolic and morphologic alterations of MDMs. Bryostatin-1 triggered the secretion of pro-inflammatory cytokines, while JQ-1 decreased it. Phagocytosis and endocytosis were modestly impaired upon bryostatin-1 treatment whereas efferocytosis was markedly downregulated by romidepsin. Despite its pro-inflammatory profile, bryostatin-1 did not induce classically activated macrophage markers. Finally, we reveal that conditioned medium from bryostatin-1-treated macrophages did not potentiate its reactivation feature.

CONCLUSIONS

Our study reveals that LRAs can diversely impact basic physiologic features of human primary macrophages and could potentially decrease reactivation of nearby CD4⁺ T cells latently infected with HIV-1. Our observations further stress the need to include different cell populations when assessing HIV-1 cure strategies.

A macrophage attack culminating in microthromboses characterizes COVID 19 pneumonia

Introduction

A neutrophilic infiltrate characterizes bacterial pneumonia. Macrophage infiltration is similarly characteristic of the viral pneumonia caused by SARS‐CoV‐2. These infiltrating macrophages, while phagocytic and capable of engulfing virus laden alveolar cells, are also rich in tissue factor—a thromboplastin. This prothrombotic aspect likely explains how a respiratory virus whose malign effects should be confined to the oropharynx, bronchi and lungs, can cause a panoply of extra‐pulmonary organ disorders. Elevated ferritin levels in ICU Covid 19 patients, and elevated acute phase proteins suggest immune overreaction. Elevated d‐dimers implicate clotting as well. This evidence links hyperactive innate immunity (macrophage lung infiltrates) with the elevated levels of oligomeric fibrin present in the bloodstream of these patients.

Methods

An in‐house assay measuring oligomeric (soluble) fibrin (also referred to as soluble fibrin monomer complexes or SFMC) in whole blood, previously developed for monitoring incipient disseminated intravascular coagulation (DIC) during liver transplantation, was made available to COVID ICU attendings. Since SFMC constitutes the input to intravascular fibrin clots and d‐dimer reflects fibrin clot dissolution, it was thought that the two tests, run in tandem along with assays of immune activation, might clarify the frequency and possibly the cause of DIC in patients with severe COVID‐19 pneumonia.

Results

Classical DIC with intravascular clotting and thrombocytopenia was documented only rarely. However, early in the pandemic shortly after the assay was made available, it identified three patients undergoing acute defibrination. In each patient virtually all of the body's fibrinogen was transformed into SFMC over 3–4 days and deposited somewhere in the vasculature without any gross clots being detected.

Conclusions

Three COVID‐19 patients with evidence of a hyperactive immune response (elevated ferritin and acute phase proteins) defibrinated while blood levels of SFMC were being monitored. SFMC levels that were five times higher than normal appeared in the circulation during the defibrination process. SFMC at these levels may precipitate as showers of microclots, damaging heart, kidney, brain, and so forth.

The new Japanese regulation on human/non-human chimeras: should we worry?

In March 2019 Japan modified its norms regarding research with human/non-human chimeras. The amended rules allow the creation of chimeras with human brain cells, and the subsequent transfer of the resulting creature to an uterus, where it can develop for more than 14 days, eventually until term. At this moment, the real consequences of this new regulation in actual research are still uncertain. However, many concerning issues have already been identified. This paper will start by addressing traditional topics involving this practice: the use of non-human animals in research, the use of human stem cells in scientific experimentation and the creation of human/non-human chimeras. Subsequently, it will analyze the new concerning issues brought on by the 2019 amendment: the use of human brain cells, the transfer of the chimera to an uterus and its development for more than 14 days, and the possibility of using animals which present close similarities with humans. In the end, the paper will conclude that in spite of the legal and ethical hazards that this new regulation might carry, it should be allowed under strict scrutiny.

Causation, Responsibility, and Harm: How the Discursive Shift from Law and Ethics to Social Justice Sealed the Plight of Nonhuman Animals

Moral and political philosophers no longer condemn harm inflicted on nonhuman animals as self-evidently as they did when animal welfare and animal rights advocacy was at the forefront in the 1980s, and sentience, suffering, species-typical behavior, and personhood were the basic concepts of the discussion. The article shows this by comparing the determination with which societies seek responsibility for human harm to the relative indifference with which law and morality react to nonhuman harm. When harm is inflicted on humans, policies concerning negligence and duty of care and principles such as the 'but for' rule and the doctrine of double effect are easily introduced. When harm is inflicted on nonhumans, this does not happen, at least not any more. As an explanation for the changed situation, the article offers a shift in discussion and its basic terminology. Simple ethical considerations supported the case for nonhuman animals, but many philosophers moved on to debate different views on political justice instead. This allowed the creation of many conflicting views that are justifiable on their own presuppositions. In the absence of a shared foundation, this fragments the discussion, focuses it on humans, and ignores or marginalizes nonhuman animals.

Emergency Contraceptives and the Beginning of Human Animals

Emergency contraceptives may sometimes prevent implantation, thereby causing the death of the embryo. According to some positions contrary to abortion, because the embryo is a human animal, there are usually decisive moral reasons not to use them. In this article, I will show that objecting to the use of emergency contraceptives on those grounds is unjustified. If organisms are real existents, then according to the most plausible conception of what is required for a group of cells to compose one, the embryo cannot qualify as a single organism. On the other hand, if organisms are virtual objects, then whether or not the embryo qualifies as one is morally irrelevant. I conclude that even if those positions are right about the morality of abortion, they are not entitled to oppose the use of emergency contraceptives.