SummaryMacrophages respond to their microenvironment and develop polarized functions critical for orchestrating appropriate inflammatory responses. Classical (M1) activation eliminates pathogens while alternative (M2) activation promotes regulation and repair. M1 macrophage activation is strongly associated with suppressor of cytokine signalling 3 (SOCS3) expression in vitro, but the functional consequences of this are unclear and the role of SOCS3 in M1-macrophage polarization in vivo remains controversial. To address these questions, we defined the characteristics and function of SOCS3-expressing macrophages in vivo and identified potential mechanisms of SOCS3 action. Macrophages infiltrating inflamed glomeruli in a model of acute nephritis show significant up-regulation of SOCS3 that co-localizes with the M1-activation marker, inducible nitric oxide synthase. Numbers of SOCS3hi-expressing, but not SOCS1hi-expressing, macrophages correlate strongly with the severity of renal injury, supporting their inflammatory role in vivo. Adoptive transfer of SOCS3-short interfering RNA-silenced macrophages into a peritonitis model demonstrated the importance of SOCS3 in driving production of pro-inflammatory IL-6 and nitric oxide, while curtailing expression of anti-inflammatory IL-10 and SOCS1. SOCS3-induced pro-inflammatory effects were due, at least in part, to its role in controlling activation and nuclear accumulation of nuclear factor-κB and activity of phosphatidylinositol 3-kinase. We show for the first time that SOCS3 also directs the functions of human monocyte-derived macrophages, including efficient M1-induced cytokine production (IL-1β, IL-6, IL-23, IL-12), attenuated signal transducer and activator of transcription 3 activity and ability of antigen-loaded macrophages to drive T-cell responses. Hence, M1-associated SOCS3 was a positive regulator of pro-inflammatory responses in our rodent models and up-regulated SOCS3 is essential for effective M1-macrophage activation and function in human macrophages.

Speech production involves widely distributed brain regions. This MEG study focuses on the spectro-temporal dynamics that contribute to the setup of this network. In 21 participants performing a cue-target reading paradigm, we analyzed local oscillations during preparation for overt and covert reading in the time-frequency domain and localized sources using beamforming. Network dynamics were studied by comparing different dynamic causal models of beta phase coupling in and between hemispheres. While a broadband low frequency effect was found for any task preparation in bilateral prefrontal cortices, preparation for overt speech production was specifically associated with left-lateralized alpha and beta suppression in temporal cortices and beta suppression in motor-related brain regions. Beta phase coupling in the entire speech production network was modulated by anticipation of overt reading. We propose that the processes underlying the setup of the speech production network connect relevant brain regions by means of beta synchronization and prepare the network for left-lateralized information routing by suppression of inhibitory alpha and beta oscillations.

Voice and speech in Parkinson's disease (PD) patients are classically affected by a hypophonia, dysprosody, and dysarthria. The underlying pathomechanisms of these disabling symptoms are not well understood. To identify functional anomalies related to pathophysiology and compensation we compared speech-related brain activity and effective connectivity in early PD patients who did not yet develop voice or speech symptoms and matched controls. During fMRI 20 PD patients ON and OFF levodopa and 20 control participants read 75 sentences covertly, overtly with neutral, or with happy intonation. A cue-target reading paradigm allowed for dissociating task preparation from execution. We found pathologically reduced striato-prefrontal preparatory effective connectivity in early PD patients associated with subcortical (OFF state) or cortical (ON state) compensatory networks. While speaking, PD patients showed signs of diminished monitoring of external auditory feedback. During generation of affective prosody, a reduced functional coupling between the ventral and dorsal striatum was observed. Our results suggest three pathomechanisms affecting speech in PD: While diminished energization on the basis of striato-prefrontal hypo-connectivity together with dysfunctional self-monitoring mechanisms could underlie hypophonia, dysarthria may result from fading speech motor representations given that they are not sufficiently well updated by external auditory feedback. A pathological interplay between the limbic and sensorimotor striatum could interfere with affective modulation of speech routines, which affects emotional prosody generation. However, early PD patients show compensatory mechanisms that could help improve future speech therapies.

Leukotriene B4 (LTB4) is a notable participant in inflammation and chemotaxis. It is, however, still unclear whether LTB4 acts in this regard directly or indirectly by stimulating the release of chemotactic and inflammatory cytokines. Here we report that LTB4 induces synthesis of interleukin (IL)-6 by human blood monocytes through transcriptional activation of the IL-6 gene. We furthermore demonstrate that this process involves activation of the transcription factor NF-chi B and, to a lesser extent, of NF-IL6, while the activity of the transcription factor AP-1, shown to otherwise confer IL-6 inducibility, appeared to be unaffected by LTB4. Involvement of NF-chi B and NF-IL6 in induction of IL-6 transcription by monocytes was demonstrated using deleted forms of the IL-6 promoter. Activation of the IL-6 promoter by LTB4 was not only associated with accumulation of the respective transcripts but resulted in synthesis of functional IL-6 protein as well. In addition, LTB4 mediated transactivation of a heterologous promoter construct containing the NF-chi B or the NF-IL6 enhancer, but not the AP-1 enhancer. The signaling events mediating this effect appeared to involve the release of H2O2, since LTB4 failed to induce NF-chi B or NF-IL6 in the presence of the scavenger of H2O2, N-acetyl-L-cysteine.

Macrophages are antigen presenting cells that can adopt different activation states as directed by microenvironmental stimuli. It is well-recognised how CD4(+) T helper (Th) signals drive macrophage activation, but the ability of differentially activated human macrophages to stimulate the major types of CD4(+) T helper (Th) response by presenting antigen have not been well defined. Previous studies have focussed on murine cells, undifferentiated human monocytes, or macrophage products, and have been limited to non-physiological mitogenic Th responses. The aim was therefore to compare the Th cell polarising abilities of different human macrophage subsets when presenting specific antigen. We demonstrate for the first time that the way macrophages are activated, while naturally presenting antigen, has profound effects on downstream adaptive immune responses. In autologous co-cultures, LPS-activation was the most potent stimulus for antigen-loaded macrophages to drive Th17 polarisation from both unfractionated CD4(+) T-cells and the CD45RO(+) memory population, while IFNγ/LPS activated macrophages preferentially induced a Th1 phenotype. By contrast, IL-4-activated macrophages were ineffective in inducing responses by either Th subset. Although antigen-loaded dendritic cells were superior to macrophages in driving Th1 responses, the Th17 polarising capacity of the two antigen-presenting cell types was equivalent, and was strongly dependent on IL-1β secretion. Taken together, these results clearly demonstrate for the first time how differentially activated human macrophages present antigen to bias specific, rather than mitogen-driven, Th responses and lead us to propose that they impact adaptive immunity in vivo, particularly in determining Th17 polarisation within inflamed tissues.

The first complete mitochondrial DNA (mtDNA) sequences (approximately 16,569 bp) in 20 patients with asthenozoospermia and a comparison with 23 new complete mtDNA sequences in teratoasthenozoospermic individuals, confirmed no sharing of specific polymorphisms or specific mitochondrial lineages between these individuals. This is strong evidence against the accepted claim of a major role played by mtDNA in male fertility, once supported by haplogroup association studies based on the screening of hypervariable region I. The hypothesis of maternally driven selection acting in male reproductive success must thus be treated with caution.

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The factors and signals driving T cell activation and polarisation during immune responses have been studied mainly at the level of cells and chemical mediators. Here we describe a physical driver of these processes in the form of physiological-strength electric fields (EFs). EFs are generated at sites where epithelium is disrupted (e.g. wounded skin/bronchial epithelia) and where T cells frequently are present. Using live-cell imaging, we show human primary T cells migrate directionally to the cathode in low strength (50/150 mV/mm) EFs. Strikingly, we show for the first time that EFs significantly downregulate T cell activation following stimulation with antigen-activated APCs or anti-CD3/CD28 antibodies, as demonstrated by decreased IL-2 secretion and proliferation. These EF-induced functional changes were accompanied by a significant dampening of CD4+ T cell polarisation. Expression of critical markers of the Th17 lineage, RORγt and IL-17, and the Th17 polarisation mediator phospho-STAT3 were reduced significantly, while STAT1, ERK and c-Jun phosphorylation were comparatively unaffected suggesting STAT3 modulation by EFs as one mechanism driving effects. Overall, we identify electrical signals as important contributors to the co-ordination and regulation of human T cell functions, paving the way for a new research area into effects of naturally occurring and clinically-applied EFs in conditions where control of T cell activity is paramount.