Neurological complications affecting the central nervous system have been reported in adult patients infected by Zika virus (ZIKV) but the underlying mechanisms remain unknown. Here, we report that ZIKV replicates in human and mouse adult brain tissue, targeting mature neurons. ZIKV preferentially targets memory-related brain regions, inhibits hippocampal long-term potentiation and induces memory impairment in adult mice. TNF-α upregulation, microgliosis and upregulation of complement system proteins, C1q and C3, are induced by ZIKV infection. Microglia are found to engulf hippocampal presynaptic terminals during acute infection. Neutralization of TNF-α signaling, blockage of microglial activation or of C1q/C3 prevent synapse and memory impairment in ZIKV-infected mice. Results suggest that ZIKV induces synapse and memory dysfunction via aberrant activation of TNF-α, microglia and complement. Our findings establish a mechanism by which ZIKV affects the adult brain, and point to the need of evaluating cognitive deficits as a potential comorbidity in ZIKV-infected adults.

Although congenital Zika virus (ZIKV) exposure has been associated with microcephaly and other neurodevelopmental disorders, long-term consequences of perinatal infection are largely unknown. We evaluated short- and long-term neuropathological and behavioral consequences of neonatal ZIKV infection in mice. ZIKV showed brain tropism, causing postnatal-onset microcephaly and several behavioral deficits in adulthood. During the acute phase of infection, mice developed frequent seizures, which were reduced by tumor necrosis factor-α (TNF-α) inhibition. During adulthood, ZIKV replication persisted in neonatally infected mice, and the animals showed increased susceptibility to chemically induced seizures, neurodegeneration, and brain calcifications. Altogether, the results show that neonatal ZIKV infection has long-term neuropathological and behavioral complications in mice and suggest that early inhibition of TNF-α-mediated neuroinflammation might be an effective therapeutic strategy to prevent the development of chronic neurological abnormalities.

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The global situation of diseases transmitted by arthropod-borne viruses such as Dengue (DENV), Yellow Fever (YFV), Chikungunya (CHIKV) and Zika (ZIKV) viruses is alarming and treatment of human infection by these arboviruses faces several challenges. The discovery of broad-spectrum antiviral molecules, able to inactivate different groups of viruses, is an interesting approach. The viral envelope is a common structure among arboviruses, being a potential target for antivirals. Porphyrins are amphipathic molecules able to interact with membranes and absorb light, being widely used in photodynamic therapy. Previously, we showed that heme, Co-protoporphyrin IX (CoPPIX) and Sn-protoporphyrin IX (SnPPIX) directly inactivate DENV and YFV infectious particles. Here we demonstrate that the antiviral activity of these porphyrins can be broadened to CHIKV, ZIKV, Mayaro virus, Sindbis virus and Vesicular Stomatitis virus. Porphyrin treatment causes viral envelope protein loss, affecting viral morphology, adsorption and entry into target cells. Also, light-stimulation enhanced the SnPPIX activity against all tested arboviruses. In summary, CoPPIX and SnPPIX were shown to be efficient broad-spectrum compounds to inactivate medically and veterinary important viruses.

These results open the possibility of therapeutic application of porphyrins or their use as models to design new antiviral drugs against DENV and YFV.

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Objectives: Survivors of sepsis are frequently left with significant cognitive and behavioral impairments. These complications derive from nonresolving inflammation that persists following hospital discharge. To date, no study has investigated the effects of mesenchymal stromal cell therapy on the blood-brain barrier, astrocyte activation, neuroinflammation, and cognitive and behavioral alterations in experimental sepsis. Design: Prospective, randomized, controlled experimental study. Setting: Government-affiliated research laboratory. Subjects: Male Swiss Webster mice (n = 309). Interventions: Sepsis was induced by cecal ligation and puncture; sham-operated animals were used as control. All animals received volume resuscitation (1 mL saline/mouse subcutaneously) and antibiotics (meropenem 10 mg/kg intraperitoneally at 6, 24, and 48 hours). Six hours after surgery, mice were treated with mesenchymal stromal cells IV (1 × 105 cells in 0.05 mL of saline/mouse) or saline (0.05 mL IV). Measurements and Main Results: At day 1, clinical score and plasma levels of inflammatory mediators were increased in cecal ligation and puncture mice. Mesenchymal stromal cells did not alter clinical score or survival rate, but reduced levels of systemic interleukin-1β, interleukin-6, and monocyte chemoattractant protein-1. At day 15, survivor mice completed a battery of cognitive and behavioral tasks. Cecal ligation and puncture mice exhibited spatial and aversive memory deficits and anxiety-like behavior. These effects may be related to increased blood-brain barrier permeability, with altered tight-junction messenger RNA expression, increased brain levels of inflammatory mediators, and astrogliosis (induced at day 3). Mesenchymal stromal cells mitigated these cognitive and behavioral alterations, as well as reduced blood-brain barrier dysfunction, astrocyte activation, and interleukin-1β, interleukin-6, tumor necrosis factor-α, and interleukin-10 levels in vivo. In cultured primary astrocytes stimulated with lipopolysaccharide, conditioned media from mesenchymal stromal cells reduced astrogliosis, interleukin-1β, and monocyte chemoattractant protein-1, suggesting a paracrine mechanism of action. Conclusions: In mice who survived experimental sepsis, mesenchymal stromal cell therapy protected blood-brain barrier integrity, reduced astrogliosis and neuroinflammation, as well as improved cognition and behavior.

The defatted fractions of the Faramea hyacinthina and F. truncata (Rubiaceae) leaf MeOH extracts showed in vitro non-cytotoxic and anti-dengue virus serotype 2 (DENV2) activity in human hepatocarcinoma cell lineage (HepG2). Submitting these fractions to the developed RP-SPE method allowed isolating the antiviral flavanone (2S)-isosakuranetin-7-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (1) from both species and yielded less active sub-fractions. The new diastereoisomeric epimer pair (2S) + (2R) of 5,3',5'-trihydroxyflavanone-7-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (2a/2b) from F. hyacinthina; the known narigenin-7-O-β-d-apiofuranosyl-(1→6)-β-d-glucopyranoside (3) from both species; rutin (4) and quercetin-4'-β-d-O-glucopyranosyl-3-O-rutinoside (5) from F. hyacinthina, and kaempferol-3-O-rutinoside (6), erythroxyloside A (7) and asperuloside (8) from F. truncata have been isolated from these sub-fractions. Compounds 4 - 8 are reported for the first time in Faramea spp.