Pro-inflammatory monocyte profile in patients with major depressive disorder and suicide behaviour and how ketamine induces anti-inflammatory M2 macrophages by NMDAR and mTOR

Wanda Nowak, Leandro Nicolás Grendas, Liliana María Sanmarco, Ivana Gisele Estecho, Ángeles Romina Arena, Natalia Eberhardt, Demián Emanuel Rodante, María Pilar Aoki, Federico Manuel Daray, Eugenio Antonio Carrera Silva, Andrea Emilse Errasti

Research output: Contribution to journalArticlepeer-review

89 Scopus citations


Background: Depression is a highly prevalent disorder that is one of the leading causes of disability worldwide. Despite an unknown aetiology, evidence suggests that the innate and adaptive immune systems play a significant role in the development and maintenance of major depressive disorder (MDD). The non-competitive glutamatergic N-methyl-D-aspartate receptor (NMDAR) antagonist, (R,S)-ketamine (ketamine), has demonstrated rapid and robust efficacy as an antidepressant when administered at sub-anaesthetic doses. Methods: Our goal was to characterize the pro-inflammatory profile of patients with MDD by measuring pro-inflammatory cytokines in plasma and circulating monocyte subsets and to understand how ketamine induces an anti-inflammatory program in monocyte and macrophages in vitro and vivo. Finding: Our results show that patients with MDD without other comorbidities (N = 33) exhibited significantly higher levels of pro-inflammatory IL-12 and IL-6 in plasma and that these cytokines were associated with increased numbers of non-classical (CD11b+CD16brightCD14neg) monocytes and increased activation state (CD40+CD86+) of classical monocytes in circulation. Remarkably, we have demonstrated that sub-anaesthetic doses of ketamine programs human monocytes into M2c-like macrophages by inducing high levels of CD163 and MERTK with intermediate levels of CD64 and stimulating mTOR-associated gene expression in vitro. The NMDAR antagonist MK-801, but not the α-amino-3‑hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) antagonist, NBQX, also polarizes macrophages to an M2c-like phenotype, but this phenotype disappears upon mTOR pathway inhibition. Sub-anaesthetic doses (10 mg/kg) of ketamine administration in mice both promote reduction of circulating classical pro-inflammatory monocytes and increase of alternative M2 macrophage subtypes in the spleen and CNS. Interpretation: Our results suggest an anti-inflammatory property of ketamine that can skew macrophages to an M2-like phenotype, highlighting potential therapeutic implications not only for patients with MDD but also other inflammatory-based diseases. Funding: This study was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Agencia Nacional de Promoción Científica y Tecnológica (ANPCyT-FONCYT).

Original languageEnglish
Pages (from-to)290-305
Number of pages16
StatePublished - Dec 2019
Externally publishedYes


  • Anti-inflammatory M2 macrophages
  • Depression
  • IL-12
  • Ketamine
  • Non-classical monocytes
  • mTOR pathway


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