Heterologous Boosting With Listeria-Based Recombinant Strains in BCG-Primed Mice Improved Protection Against Pulmonary Mycobacterial Infection

Cordyceps proteins alleviate lupus nephritis through modulation of the STAT3/mTOR/NF-кB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Cordyceps is a parasitic edible fungus, which is a unique Chinese medicinal material. It has been reported to have immunomodulatory effects and use in kidney disease. Especially, Cordyceps has been used in the treatment of lupus nephritis (LN).

AIM OF STUDY

Cordyceps proteins (CP) have a favorable bidirectional immunomodulatory functions and may have therapeutic potential for LN. However, the underlying molecular mechanism remains unknown. So this study aimed to examine the activities of CP in LN and possible mechanism.

MATERIALS AND METHODS

So proteomics was performed to detect proteins components of Cordyceps, and analysis it. In addition, MRL/lpr mice were used to study the progression of LN. The MRL/lpr mice were fed either CP (i.g, 0.5, 1.0, 1.5 g/kg/d), prednisolone acetate (PA, i.g, 6 mg/kg/d), or Bailing capsule (BC, i.g, 0.75 g/kg/d) for 8 weeks. Hematoxylin-eosin (H&E), Periodic Acid Schif (PAS) and Masson's stainings, Immunofluorescence, and Immunohistochemistry were performed to verify the therapeutic effect of CP on MRL/lpr mice. The mechanism by CP alimerated LN was uncovered by Western blotting (WB) and Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) methods.

RESULTS

Our results revealed that CP blocked proteinuria production and renal inflammatory infiltratation in MRL/lpr mice to reduce the renal fibrosis. In addition, CP worked better than BC which is artificial Cordyceps fungus powder in regulating proteinuria to urine creatinine ratio and interleukin-4(IL-4) protein amount. Especially, CP modulated the STAT3/mTOR/NF-кB signaling pathway in LN mice and brought a more pronounced lowering effect on the contents of IL-6 and IL-1β than the PA.

CONCLUSION

CP could be a potential anti-inflammatory immune product with strong regulatory effects and potency than BC and PA in nephritis therapeutics.

A Listeria ivanovii balanced-lethal system may be a promising antigen carrier for vaccine construction

Expressing heterologous antigens by plasmids may cause antibiotic resistance. Additionally, antigen expression via plasmids is unstable due to the loss of the plasmid. Here, we developed a balanced‐lethal system. The Listeria monocytogenes (LM) balanced‐lethal system has been previously used as an antigen carrier to induce cellular immune response. However, thus far, there has been no reports on Listeria ivanovii (LI) balanced‐lethal systems. The dal and dat genes from the LI‐attenuated LIΔatcAplcB (LIΔ) were deleted consecutively, resulting in a nutrient‐deficient LIΔdd strain. Subsequently, an antibiotic resistance‐free plasmid carrying the LM dal gene was transformed into the nutrient‐deficient strain to generate the LI balanced‐lethal system LIΔdd:dal. The resultant bacterial strain retains the ability to proliferate in phagocytic cells, as well as the ability to adhere and invade hepatocytes. Its genetic composition was stable, and compared to the parent strain, the balanced‐lethal system was substantially attenuated. In addition, LIΔdd:dal induced specific CD4⁺/CD8⁺ T‐cell responses and protected mice against LIΔ challenge. Similarly, we constructed an LM balanced‐lethal system LMΔdd:dal. Sequential immunization with different recombinant Listeria strains will significantly enhance the immunotherapeutic effect. Thus, LIΔdd:dal combined with LMΔdd:dal, or with other balanced‐lethal systems will be more promising alternative for vaccine development.

Recombinant Listeria ivanovii strain expressing listeriolysin O in place of ivanolysin O might be a potential antigen carrier for vaccine construction

Listeria monocytogenes (LM) induces efficient and specific T-cell immune responses in the host. Listeriolysin O (LLO) is the main virulence protein of LM. LLO helps LM escape from the lysosome. However, the pronounced pathogenicity of LM limits its practical application as a live bacterial vector. Listeria ivanovii (LI) also displays intracellular parasitic abilities, cell to cell transfer, and other LM properties, with an elevated biosafety relative to LM. We have confirmed that LI can be used as a viable bacterial vaccine vector. However, we have also observed in vivo that LI vector vaccine candidates survive in the immune organ (spleen) for a shorter time compared with the survival time of LM and elicit weaker immune responses compared with LM. Studies have confirmed that hemolysin correlates with some important biological properties of Listeria, including cell invasion, intracellular proliferation, and the ability to induce immune responses. We speculated that the weaker immunogenicity of LI compared to LM may be related to the function of ivanolysin O (ILO). Here, we established a hemolysin gene deletion strain, LIΔilo, and a modified strain, LIΔilo:hly, whose ilo was replaced by hly. The hemolysin-modified strain was attenuated; however, it led to significantly improved invasive and proliferative activities of antigen-presenting cells, including those of RAW 264.7 macrophages, compared with the effects of LI. Mice immunized twice with LIΔilo:hly showed higher cytokine levels and better challenge protection rates than LI-immunized mice. This is the first description in Listeria carrier vaccine research of the modification of LI hemolysin to obtain a better vaccine carrier than LI. The recombinant strain LIΔilo:hly showed good biosafety and immunogenicity, and thus appears to be a good vector strain for vaccine development.

Hemolysin function of Listeria is related to biofilm formation: transcriptomics analysis

Listeriolysin O (LLO) is the main virulence protein of Listeria monocytogenes (LM), that helps LM escape lysosomes. We previously found that the cellular immune response elicited by L.ivanovii (LI) is weaker than that elicited by LM. We speculated that this may be related to the function of ivanolysin O (ILO). Here, we constructed hemolysin gene deletion strain, LIΔilo, and a modified strain, LIΔilo::hly, in which ilo was replaced by hly. Prokaryotic transcriptome sequencing was performed on LI, LIΔilo, and LIΔilo::hly. Transcriptome differences between the three strains were compared, and genes and pathways with significant differences between the three strains were analyzed. Prokaryotic transcriptome sequencing results revealed the relationship of ilo to the ribosome, quorum sensing, and phosphotransferase system (PTS) pathways, etc. LIΔilo exhibited attenuated biofilm formation ability compared to LI. Biofilm formation was significantly recovered or even increased after replenishing hly. After knocking out ilo, the relative expression levels of some virulence genes, including sigB, prfA, actA, smcL, and virR, were up-regulated compared to LI. After replenishing hly, these genes were down-regulated compared to LIΔilo. The trend and degree of such variation were not completely consistent when cultured in media containing only monosaccharides or disaccharides. The results confirmed that hemolysin is related to some important biological properties of Listeria, including biofilm formation and virulence gene expression levels. This is the first comprehensive study on ILO function at the transcriptomic level and the first evidence of a relationship between Listeria hemolysin and biofilm formation.