M1 and M2a Polarization of Human Monocyte-Derived Macrophages Inhibits HIV-1 Replication by Distinct Mechanisms

Abstract

The capacity of macrophages to support productive HIV-1 infection is known to be modulated by cytokines and other extracellular stimuli. In this study, we demonstrate that cytokine-induced polarization of human monocyte-derived macrophage (MDM) into either classical (M1) or alternatively activated (M2a) MDM is associated with a reduced capacity to support productive CCR5-dependent (R5) HIV-1 infection. M1 polarization was associated with a significant down-regulation of CD4 receptors, increased secretion of CCR5-binding chemokines (CCL3, CCL4, and CCL5), and a >90% decrease in HIV-1 DNA levels 48-h postinfection, suggesting that the inhibition occurred at an early preintegration step in the viral life cycle. In contrast, M2a polarization had no effect on either HIV-1 DNA or protein expression levels, indicating that inhibition occurred at a late/postintegration level in the viral life cycle. M2a inhibition was sustained for up to 72-h postinfection, whereas M1-effects were more short-lived. Most phenotypic and functional changes were fully reversible 7 days after removal of the polarizing stimulus, and a reciprocal down-regulation of M1-related chemokines and cytokines was observed in M2a MDM and vice versa. Since reversion to a nonpolarized MDM state was associated with a renewed capacity to support HIV replication to control levels, M1/M2a polarization may represent a mechanism that allows macrophages to cycle between latent and productive HIV-1 infection.

HIV-1–Mediated BAFF Secretion in Macrophages Does Not Require Endosomal TLRs, Type-I IFN, and Nef, but Depends on the Cellular Phenotype Status

“…HIV-1 replication was lower in M2a cells compared with M0 MDMs and was almost totally inhibited in M1 MDMs (Fig. 7B), which is in agreement with previous observations (72). Analysis of BAFF secretion in infected or uninfected polarized or control MDM supernatants following 12 d of incubation revealed that HIV-1 stimulates BAFF production in M0 and M2a MDMs but not in M1 cells (Fig.…”

Human IL10 Gene Repression by Rev-erbα Ameliorates Mycobacterium tuberculosis Clearance

“…After 5-6 days, these MDMs (Ͼ95% CD14) were stimulated by IFN␥ (50 ng/ml) and LPS (10 ng/ml) or IL4 (50 ng/ml) for another 24 h (supplemental Fig. 2) (25,26).…”

“…After 5-6 days, these MDMs (Ͼ95% CD14) were stimulated by IFN␥ (50 ng/ml) and LPS (10 ng/ml) or IL4 (50 ng/ml) for another 24 h (supplemental Fig. 2) (25,26).Transfection and Transduction-siRNA and/or plasmids were transfected into the cells by using Lipofectamine Plus reagent according to the manufacturer's instructions (Invitrogen). Overexpression of Rev-erb␣ was performed by infecting primary human monocyte-derived macrophages with adenoviral particles (500 -1000 plaque-forming units/cell) in Opti-MEM for 2-4 h followed by the addition of fresh medium and additional incubation of 24 h.…”

Splenic Damage during SIV Infection

“…96 In addition, polarization is extremely important as it shifts macrophages from a state of active to latent viral infection. 97 A model was proposed in which macrophages changed from M1 to M2 polarization during the transition from early to late stage disease, which promoted their latent infection and the formation of a steady-state viral reservoir. 98 The loss of a polarized phenotype promoted active macrophage viral replication and the production of infectious virus, 97 suggesting that polarization-reversing agents must be considered when developing shock and kill therapeutic strategies.…”