Vaccination induces rapid protection against bacterial pneumonia via training alveolar macrophage in mice

Vaccination strategies for rapid protection against multidrug-resistant bacterial infection are very important, especially for hospitalized patients who have high risk of exposure to these bacteria. However, few such vaccination strategies exist due to a shortage of knowledge supporting their rapid effect. Here, we demonstrated that a single intranasal immunization of inactivated whole cell of Acinetobacter baumannii elicits rapid protection against broad A. baumannii-infected pneumonia via training of innate immune response in Rag1-/- mice. Immunization-trained alveolar macrophages (AMs) showed enhanced TNF-α production upon restimulation. Adoptive transfer of immunization-trained AMs into naive mice mediated rapid protection against infection. Elevated TLR4 expression on vaccination-trained AMs contributed to rapid protection. Moreover, immunization-induced rapid protection was also seen in Pseudomonas aeruginosa and Klebsiella pneumoniae pneumonia models, but not in Staphylococcus aureus and Streptococcus pneumoniae model. Our data reveal that a single intranasal immunization induces rapid and efficient protection against certain Gram-negative bacterial pneumonia via training AMs response, which highlights the importance and the possibility of harnessing trained immunity of AMs to design rapid-effecting vaccine.

Xiangqing anodyne spray (XQAS): a combination of ethanol extracts of Cynanchum paniculatum and Illicium henryi for treating soft-tissue injury

PURPOSE

To compare the pharmacodynamic effects of an anodyne spray (XQAS) containing extracts of two herbs, Cynanchum paniculatum (CP) and Illicium henryi (IH), with those of spray containing the vehicle alone, CP alone (CPS) or IH alone (IHS), when applied topically acute soft tissue injury (STI) in an animal model.

METHODS

Acute closed STI was modeled by hammer blow in the hind leg muscle of rat. In the acute test, XQAS, vehicle and normal saline (NS) were applied topically with instantly and repeatedly every 2 h for 8 h after modeling. In the chronic test, XQAS, vehicle, NS, CPS and IHS were applied topically respectively with instantly and repeatedly every 8 h for 96 h after modeling.

RESULTS

XQAS (150 μl/time) rapidly suppressed STI-caused muscle swelling, high contents of inflammatory mediators such as prostaglandin-E2, interleukin-lβ, nitric oxide and so on. XQAS (100 and 250 μl/time) also showed chronic effects with dose-dependent suppressions of muscle swelling, up-regulated mRNA expressions of nuclear factor-κB p65 (NF-κB p65), cyclooxygenase-2 and interleukin-lβ, high contents of inflammatory mediators, and muscle cells impairment and necrosis induced by STI, while XQAS was more effective than CPS or HIS on treating STI.

CONCLUSION

XQAS can suppress STI-caused increased gene expressions of NF-κB p65 and its downstream genes which mediate biosyntheses of inflammatory mediators, resulting in suppressed swelling, inflammatory reaction and cell impairment in the injured muscle. There is a synergistic effect between CPS and IHS on curing STI.

Acute modulation of synaptic plasticity of pyramidal neurons by activin in adult hippocampus

Activin A is known as a neuroprotective factor produced upon acute excitotoxic injury of the hippocampus (in pathological states). We attempt to reveal the role of activin as a neuromodulator in the adult male hippocampus under physiological conditions (in healthy states), which remains largely unknown. We showed endogenous/basal expression of activin in the hippocampal neurons. Localization of activin receptors in dendritic spines (=postsynapses) was demonstrated by immunoelectron microscopy. The incubation of hippocampal acute slices with activin A (10 ng/mL, 0.4 nM) for 2 h altered the density and morphology of spines in CA1 pyramidal neurons. The total spine density increased by 1.2-fold upon activin treatments. Activin selectively increased the density of large-head spines, without affecting middle-head and small-head spines. Blocking Erk/MAPK, PKA, or PKC prevented the activin-induced spinogenesis by reducing the density of large-head spines, independent of Smad-induced gene transcription which usually takes more than several hours. Incubation of acute slices with activin for 2 h induced the moderate early long-term potentiation (moderate LTP) upon weak theta burst stimuli. This moderate LTP induction was blocked by follistatin, MAPK inhibitor (PD98059) and inhibitor of NR2B subunit of NMDA receptors (Ro25-6981). It should be noted that the weak theta burst stimuli alone cannot induce moderate LTP. These results suggest that MAPK-induced phosphorylation of NMDA receptors (including NR2B) may play an important role for activin-induced moderate LTP. Taken together, the current results reveal interesting physiological roles of endogenous activin as a rapid synaptic modulator in the adult hippocampus.