Effects of Parvovirus B19 In Vitro Infection on Monocytes from Patients with Systemic Sclerosis: Enhanced Inflammatory Pathways by Caspase-1 Activation and Cytokine Production

Parvovirus B19 (B19V) has been proposed as a triggering agent for some autoimmune diseases including systemic sclerosis (SSc). In this study, we investigated whether B19V infection in vitro differently activates inflammatory pathways, including those dependent on caspase-1 activation, in monocytes from patients with SSc and healthy controls. We showed that B19V can infect both THP-1 cells and primary monocytes but is not able to replicate in these cells. B19V infection increases the production of tumor necrosis factor-\u3b1 and induces NLRP3-mediated caspase-1 activation in both THP-1 cells differentiated with phorbol 12-myristate 13-acetate and in monocytes from patients with SSc but not from healthy controls. B19V infection was sufficient for THP-1 to produce mature IL-1\u3b2. Monocytes from patients with SSc required an additional stimulus, here represented by lipopolysaccharides, to activate cytokine genes. Following B19V infection, however, lipopolysaccharide-activated monocytes from patients with SSc strongly increased the production of IL-1\u3b2 and tumor necrosis factor-\u3b1. Altogether, these data suggest that viral components might potentiate the response to endogenous and/or exogenous toll-like receptor 4 ligands in monocytes from patients with SSc. The B19V-mediated activation of inflammatory pathways in monocytes might contribute to the disease progression and/or development of specific clinical phenotypes

Bridging pro-inflammatory signals, synaptic transmission and protection in spinal explants in vitro

Multiple sclerosis is characterized by tissue atrophy involving the brain and the spinal cord, where reactive inflammation contributes to the neurodegenerative processes. Recently, the presence of synapse alterations induced by the inflammatory responses was suggested by experimental and clinical observations, in experimental autoimmune encephalomyelitis mouse model and in patients, respectively. Further knowledge on the interplay between pro-inflammatory agents, neuroglia and synaptic dysfunction is crucial to the design of unconventional protective molecules. Here we report the effects, on spinal cord circuits, of a cytokine cocktail that partly mimics the signature of T lymphocytes sub population Th1. In embryonic mouse spinal organ-cultures, containing neuronal cells and neuroglia, cytokines induced inflammatory responses accompanied by a significant increase in spontaneous synaptic activity. We suggest that cytokines specifically altered signal integration in spinal networks by speeding the decay of GABAA responses. This hypothesis is supported by the finding that synapse protection by a non-peptidic NGF mimetic molecule prevented both the changes in the time course of GABA events and in network activity that were left unchanged by the cytokine production from astrocytes and microglia present in the cultured tissue. In conclusion, we developed an important tool for the study of synaptic alterations induced by inflammation, that takes into account the role of neuronal and not neuronal resident cells

Vaginal lactobacilli and vaginal dysbiosis-associated bacteria differently affect cervical epithelial and immune homeostasis and anti-viral defenses

Persistent infection with High Risk-Human Papilloma Viruses (HR-HPVs) is a primary cause of cervical cancer worldwide. Vaginal-dysbiosis-associated bacteria were correlated with the persistence of HR-HPVs infection and with increased cancer risk. We obtained strains of the most represented bacterial species in vaginal microbiota and evaluated their effects on the survival of cervical epithelial cells and immune homeostasis. The contribution of each species to supporting the antiviral response was also studied. Epithelial cell viability was affected by culture supernatants of most vaginal-dysbiosis bacteria, whereas Lactobacillus gasseri or Lactobacillus jensenii resulted in the best stimulus to induce interferon-γ (IFN-γ) production by human mononuclear cells from peripheral blood (PBMCs). Although vaginal-dysbiosis-associated bacteria induced the IFN-γ production, they were also optimal stimuli to interleukin-17 (IL-17) production. A positive correlation between IL-17 and IFN-γ secretion was observed in cultures of PBMCs with all vaginal-dysbiosis-associated bacteria suggesting that the adaptive immune response induced by these strains is not dominated by T(H)1 differentiation with reduced availability of IFN-γ, cytokine most effective in supporting virus clearance. Based on these results, we suggest that a vaginal microbiota dominated by lactobacilli, especially by L. gasseri or L. jensenii, may be able to assist immune cells with clearing HPV infection, bypasses the viral escape and restores immune homeostasis

Differences in Inflammatory Response Induced by Two Representatives of Clades of the Pandemic ST258 Klebsiella pneumoniae Clonal Lineage Producing KPC-Type Carbapenemases

ST258-K. pneumoniae (ST258-KP) strains, the most widespread multidrug-resistant hospital-acquired pathogens, belong to at least two clades differing in a 215 Kb genomic region that includes the cluster of capsule genes. To investigate the effects of the different capsular phenotype on host-pathogen interactions, we studied representatives of ST258-KP clades, KKBO-1 and KK207-1, for their ability to activate monocytes and myeloid dendritic cells from human immune competent hosts. The two ST258-KP strains strongly induced the production of inflammatory cytokines. Significant differences between the strains were found in their ability to induce the production of IL-1β: KK207-1/clade I was much less effective than KKBO-1/clade II in inducing IL-1β production by monocytes and dendritic cells. The activation of NLRP3 inflammasome pathway by live cells and/or purified capsular polysaccharides was studied in monocytes and dendritic cells. We found that glibenclamide, a NLRP3 inhibitor, inhibits more than 90% of the production of mature IL-1β induced by KKBO1 and KK207-1. KK207-1 was always less efficient compared to KKBO-1 in: a) inducing NLRP3 and pro-IL-1β gene and protein expression; b) in inducing caspase-1 activation and pro-IL-1β cleavage. Capsular composition may play a role in the differential inflammatory response induced by the ST258-KP strains since capsular polysaccharides purified from bacterial cells affect NLRP3 and pro-IL-1β gene expression through p38MAPK- and NF-êB-mediated pathways. In each of these functions, capsular polysaccharides from KK207-1 were significantly less efficient compared to those purified from KKBO-1. On the whole, our data suggest that the change in capsular phenotype may help bacterial cells of clade I to partially escape innate immune recognition and IL-1β-mediated inflammation

Differential Th17 response induced by the two clades of the pandemic ST258 Klebsiella pneumoniae clonal lineages producing KPC-type carbapenemase

The spread of KPC-type carbapenemases is mainly attributed to the global dissemination of Klebsiella pneumoniae (KP) strains belonging to the clonal group (CG) 258, including sequence type (ST) 258 and other related STs. Two distinct clades of CG258-KP have evolved, which differ mainly for the composition of their capsular polysaccharides, and recent studies indicate that clade 1 evolved from an ancestor of clade 2 by recombination of a genomic fragment carrying the capsular polysaccharide (cps) locus. In this paper, we investigated the ability of two ST258-KP strains, KKBO-1 and KK207-1, selected as representatives of ST258-KP clade 2 and clade 1, respectively, to activate an adaptive immune response using ex vivo-stimulation of PBMC from normal donors as an experimental model. Our data showed that KKBO-1 (clade 2) induces a Th17 response more efficiently than KK207-1 (clade 1): the percentage of CD4+ IL17+ cells and the production of IL-17A were significantly higher in cultures with KKBO-1 compared to cultures with KK207-1. While no differences in the rate of bacterial internalization or in the bacteria-induced expression of CD86 and HLA-DR by monocytes and myeloid dendritic cells were revealed, we found that the two strains significantly differ in inducing the production of cytokines involved in the adaptive immune response, as IL-1β, IL-23 and TNF-α, by antigen-presenting cells, with KKBO-1 being a more efficient inducer than KK207-1. The immune responses elicited by KK207-1 were comparable to those elicited by CIP 52.145, a highly virulent K. pneumoniae reference strain known to escape immune-inflammatory responses. Altogether, present results suggest that CG258-KP of the two clades are capable of inducing a different response of adaptive immunity in the human host

Hypervirulent Klebsiella pneumoniae Strains Modulate Human Dendritic Cell Functions and Affect TH1/TH17 Response

none13noHypervirulent Klebsiella pneumoniae (Hv‐Kp) strains have emerged as pathogens causing life‐threatening, invasive disease even in immunocompetent hosts. Systemic dissemination usually occurs following perturbations of the gut microbiota and is facilitated by Hv‐Kp resistance to phagocytosis and complement activity. Hv‐Kp are usually associated with K1 or K2 capsular types, produce several iron uptake systems (e.g., aerobactin and salmochelin) and are often but not invariably, capsular material hyper‐producers (hypermucoviscous phenotype: HMV). Whether Hv‐ Kp escape the immune response at mucosal site is unknown. In this work, we studied the effects of Hv‐Kp on human dendritic cells (DCs), central players of the IL‐23/IL‐17 and IL‐12/IFN‐γ axis at mucosal sites, essential for pathogen clearance. Four Hv‐Kp and HMV strains were selected and their activity on DC maturation and cytokine production was compared to that of non‐virulent Kp strains with classic or HMV phenotypes. While the maturation process was equally induced by all Kp strains, significant differences between virulent and non‐virulent strains were found in the expression of genes for cytokines involved in T‐cell activation and differentiation. The non‐virulent KP04C62 and the classic Kp, KPC157 induced high expression of TH1 (IL‐12p70 and TNFα) and TH17 cytokines (IL‐23, IL‐1β and IL‐6), while Hv‐Kp poorly activated these cytokine genes. Moreover, conditioned media from DCs cultured with non‐virulent Kp, either classical or hypercapsulated, induced the activation of IL‐17 and IFN‐γ genes in preactivated CD4+‐cells suggesting their TH17/TH1 differentiation. Conditioned media from Hv‐Kp poorly activated IL‐17 and IFN‐γ genes. In summary, our data indicate that Hv‐Kp interfere with DC functions and T‐cell differentiation and suggest that the escape from the IL‐23/IL‐17 and IL‐12/IFN‐γ axes may contribute to pathogen dissemination in immunocompetent hosts.noneNicolo S.; Mattiuz G.; Antonelli A.; Arena F.; Di Pilato V.; Giani T.; Baccani I.; Clemente A.M.; Castronovo G.; Tanturli M.; Cozzolino F.; Rossolini G.M.; Torcia M.G.Nicolo, S.; Mattiuz, G.; Antonelli, A.; Arena, F.; Di Pilato, V.; Giani, T.; Baccani, I.; Clemente, A. M.; Castronovo, G.; Tanturli, M.; Cozzolino, F.; Rossolini, G. M.; Torcia, M. G

Additional file 2: of Bridging pro-inflammatory signals, synaptic transmission and protection in spinal explants in vitro

The frequency and amplitude of GABAergic PSCs were not affected by CKs treatments in the absence of in the presence of MT2. Box-plots summarize the frequency (A) and the amplitude (B) of IPSCs prior and after CKs incubation in both the absence and the presence of MT2. (C) The plots show the absence of linear correlation between the decay time constant and rise time of IPSCs in all the conditions tested. (TIFF 777 kb

Additional file 2: of Bridging pro-inflammatory signals, synaptic transmission and protection in spinal explants in vitro

The frequency and amplitude of GABAergic PSCs were not affected by CKs treatments in the absence of in the presence of MT2. Box-plots summarize the frequency (A) and the amplitude (B) of IPSCs prior and after CKs incubation in both the absence and the presence of MT2. (C) The plots show the absence of linear correlation between the decay time constant and rise time of IPSCs in all the conditions tested. (TIFF 777 kb