The 70 kDa heat shock protein (HSP70) is a stress-inducible protein that has been shown to protect the brain from various nervous system injuries. It allows cells to withstand potentially lethal insults through its chaperone functions. Its chaperone properties can assist in protein folding and prevent protein aggregation following several of these insults. Although its neuroprotective properties have been largely attributed to its chaperone functions, HSP70 may interact directly with proteins involved in cell death and inflammatory pathways following injury. Through the use of mutant animal models, gene transfer, or heat stress, a number of studies have now reported positive outcomes of HSP70 induction. However, these approaches are not practical for clinical translation. Thus, pharmaceutical compounds that can induce HSP70, mostly by inhibiting HSP90, have been investigated as potential therapies to mitigate neurological disease and lead to neuroprotection. This review summarizes the neuroprotective mechanisms of HSP70 and discusses potential ways in which this endogenous therapeutic molecule could be practically induced by pharmacological means to ultimately improve neurological outcomes in acute neurological disease.

Hypoxic-ischemic brain damage (HIBD) is a common cause of infant death. The purpose of our research was to explore the immunoregulatory mechanism of placenta-derived mesenchymal stem cells (PD-MSCs) in HIBD treatment. Seven-day-old rat pups were randomly divided into HIBD, PD-MSC, fibroblast, and control groups. Forty-eight hours after HIBD induction, cells at a density of 5 × 104 cells/10 µl were injected into the cerebral tissue in the PD-MSC and fibroblast groups. The TNF-α, interleukin- 17 (IL-17), interferon-γ (IFN-γ), and IL-10 levels were detected through quantitative real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Regulatory T cell (Tregs) populations were detected through flow cytometry, and forkhead box P3 (Foxp3) was measured through western blot analysis. Behavioral tests and gross and pathological examinations showed that PD-MSC treatment exerted significantly stronger neuroprotective effects than the other treatments. The expression levels of pro-inflammatory cytokines were substantially upregulated after HI injury. Compared with fibroblast treatment, PD-MSC treatment inhibited the production of pro-inflammatory cytokines and increased the production of IL-10 in the ischemic hemispheres and peripheral blood serum (all P < 0.01). Flow cytometry results showed a notable increase in the number of Tregs within the spleen of the HIBD group. Moreover, the number of Tregs and the Foxp3 expression levels were higher in the PD-MSC treatment group than in the HIBD and fibroblast groups (all P < 0.01). Our research suggests that the mechanism of PD-MSC treatment for HIBD partially involves inflammatory response suppression.

Evolutionary outcomes depend not only on the selective forces acting upon a species, but also on the genetic background. However, large timescales and uncertain historical selection pressures can make it difficult to discern such important background differences between species. Experimental evolution is one tool to compare evolutionary potential of known genotypes in a controlled environment. Here we utilized a highly reproducible evolutionary adaptation in Saccharomyces cerevisiae to investigate whether experimental evolution of other yeast species would select for similar adaptive mutations. We evolved populations of S. cerevisiae, S. paradoxus, S. mikatae, S. uvarum, and interspecific hybrids between S. uvarum and S. cerevisiae for ~200–500 generations in sulfate-limited continuous culture. Wild-type S. cerevisiae cultures invariably amplify the high affinity sulfate transporter gene, SUL1. However, while amplification of the SUL1 locus was detected in S. paradoxus and S. mikatae populations, S. uvarum cultures instead selected for amplification of the paralog, SUL2. We measured the relative fitness of strains bearing deletions and amplifications of both SUL genes from different species, confirming that, converse to S. cerevisiae, S. uvarum SUL2 contributes more to fitness in sulfate limitation than S. uvarum SUL1. By measuring the fitness and gene expression of chimeric promoter-ORF constructs, we were able to delineate the cause of this differential fitness effect primarily to the promoter of S. uvarum SUL1. Our data show evidence of differential sub-functionalization among the sulfate transporters across Saccharomyces species through recent changes in noncoding sequence. Furthermore, these results show a clear example of how such background differences due to paralog divergence can drive changes in genome evolution.

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The link between carcinogen exposure and cancer immunogenicity is unclear. Single exposure to 12-dimethylbenz[a]anthracene (DMBA) at puberty accelerated spontaneous breast carcinogenesis in mouse mammary tumor virus-polyoma middle tumor-antigen transgenic (MMTV-PyMTtg or PyMT) and MMTV-Her2/neutg (Her2) mice. Paradoxically, DMBA-treated PyMT and Her2 animals were protected from metastasis. CD8+ T cells significantly infiltrated DMBA-exposed breast cancers. CD8+ T cell depletion resulted in severe lung and liver metastasis in DMBA-treated PyMT mice. Besides increasing tumor mutational burden, DMBA exposure up-regulated Chemokine (C-C motif) ligand 21 (CCL21) in cancer cells and heightened antigen presentation. CCL21 injection suppressed breast cancer growth, and CCL21 receptor deletion attenuated T cell immunity against cancer metastasis in DMBA-treated PyMT animals. CCL21 expression correlated with increased mutational burden and cytolytic activity across human cancers. Higher CCL21 levels correlated with increased CD8+ T cell infiltrates in human breast cancer and predicted lower breast cancer distant recurrence rate. Collectively, carcinogen exposure induces immune-activating factors within cancer cells that promote CD8+ T cell immunity against metastasis.