Targeting the JAK2-STAT3 pathway to inhibit cGAS-STING activation improves neuronal senescence after ischemic stroke.

Neuroinflammation after cerebral ischemia is a key event in progressive brain injury after ischemic stroke. The JAK2/STAT3 pathway is pivotal for neuroinflammation; however, its role in brain senescence after ischemic stroke is unclear. Here, we report that inflammation is increased in the brains of C57BL/6 stroke mice. Treatment of ischemic stroke in adult mice with a JAK kinase inhibitor (AG490) alleviated neurobehavioral defects, reduced brain infarct volume, reduced expression of pro-inflammatory cytokines, and decreased activation of pro-inflammatory microglia. Moreover, AG490 treatment reduced oxidative DNA damage and cellular senescence in the brains of mice following ischemic stroke. Cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING) were associated with inflammation and senescence. Furthermore, AG490 blocked cGAS/STING/NF-κBp65 expression. Overall, our results indicate that inhibition of JAK2/STAT3 can alleviate the negative neurological consequences of ischemic stroke, likely due to repression of cGAS/STING/NF-κB p65, leading to reduced neuroinflammation and neuronal senescence. Therefore, JAK2/STAT3 may represent a viable therapeutic target for preventing senescence after ischemic stroke.

Engineering Escherichia coli Nissle 1917 as a microbial chassis for therapeutic and industrial applications.

Genetically engineered microbes, especially Escherichia coli, have been widely used in the biosynthesis of proteins and metabolites for medical and industrial applications. As a traditional probiotic with a well-established safety record, E. coli Nissle 1917 (EcN) has recently emerged as a microbial chassis for generating living therapeutics, drug delivery vehicles, and microbial platforms for industrial production. Despite the availability of genetic tools for engineering laboratory E. coli K-12 and B strains, new genetic engineering systems are still greatly needed to expand the application range of EcN. In this review, we have summarized the latest progress in the development of genetic engineering systems in EcN, as well as their applications in the biosynthesis and delivery of valuable small molecules and biomacromolecules of medical and/or industrial interest, followed by a glimpse of how this rapidly growing field will evolve in the future.

Development of probiotic E. coli Nissle 1917 for ß-alanine production by using protein and metabolic engineering.

ß-alanine has been used in food and pharmaceutical industries. Although Escherichia coli Nissle 1917 (EcN) is generally considered safe and engineered as living therapeutics, engineering EcN for producing industrial metabolites has rarely been explored. Here, by protein and metabolic engineering, EcN was engineered for producing ß-alanine from glucose. First, an aspartate-α-decarboxylase variant ADCK43Y with improved activity was identified and over-expressed in EcN, promoting the titer of ß-alanine from an undetectable level to 0.46 g/L. Second, directing the metabolic flux towards L-aspartate increased the titer of ß-alanine to 0.92 g/L. Third, the yield of ß-alanine was elevated to 1.19 g/L by blocking conversion of phosphoenolpyruvate to pyruvate, and further increased to 2.14 g/L through optimizing culture medium. Finally, the engineered EcN produced 11.9 g/L ß-alanine in fed-batch fermentation. Our work not only shows the potential of EcN as a valuable industrial platform, but also facilitates production of ß-alanine via fermentation. KEY POINTS: • Escherichia coli Nissle 1917 (EcN) was engineered as a ß-alanine producing cell factory • Identification of a decarboxylase variant ADCK43Y with improved activity • Directing the metabolic flux to L-ASP and expressing ADCK43Y elevated the titer of ß-alanine to 11.9 g/L.

Tuberculosis-specific antigen stimulated and unstimulated interferon-γ for tuberculous meningitis diagnosis: A systematic review and meta-analysis.

OBJECTIVE: Tuberculous meningitis (TBM) is one of the most devastating TB. Accurate identification of TBM is helpful to eliminate TB. Therefore, we assessed the performance of TBAg stimulated IFN-γ (IGRA) and unstimulated IFN-γ in blood and cerebrospinal fluid (CSF) for diagnosing TBM. METHODS: We searched Web of Science, PubMed, Embase and the Cochrane Library databases until March 2022. Bivariate and hierarchical summary receiver operating characteristic models were employed to compute summary estimates for diagnostic accuracy parameters of IGRA and unstimulated IFN-γ in blood and CSF for diagnosing TBM. RESULTS: 28 studies including 1,978 participants and 2,641 samples met the inclusion criteria. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR) and area under the curve (AUROC) of blood IGRA were separately as 0.73, 0.83, 4.32, 0.33, 13.22 and 0.86, indicating a good diagnostic accuracy of blood IGRA for detecting TBM. The summary sensitivity, specificity, PLR, NLR, DOR and AUROC of CSF IGRA were separately as 0.77, 0.91, 8.82, 0.25, 34.59 and 0.93, indicating good diagnostic accuracy of CSF IGRA for detecting TBM. The summary sensitivity, specificity, PLR, NLR, DOR and AUROC of CSF IFN-γ were separately as 0.86, 0.92, 10.27, 0.16, 65.26 and 0.95, suggesting CSF IFN-γ provided excellent accuracy for diagnosing TBM. CONCLUSIONS: For differentiating TBM from non-TBM individuals, blood and CSF IGRA are good assays and unstimulated CSF IFN-γ is an auxiliary excellent marker.

Coexistence of Lung Squamous Cell Carcinoma and Pulmonary Tuberculosis Within a Single Lesion: A Case Report.

Pulmonary tuberculosis (TB) and lung cancer are both common diseases with poor prognosis and high mortality worldwide. The coexistence of the two diseases has rarely been reported while their relationship has been noted. Here we describe a patient diagnosed with both TB and squamous cell carcinoma in a single lesion. The patient had a cough for four months and polypnea for two months, with a smoking history of over 40 years. Chest computed tomography (CT) showed a lobular mass in the right hilar region, which was diagnosed as TB by transbronchial lung biopsy. The symptoms and CT findings indicated the possibility of lung cancer. So, the patient underwent a further lung biopsy at the periphery of the mass, which was confirmed as squamous cell carcinoma. This case illuminated that when the mass with cancer-like morphologic features and location instead of typical TB, even the initial pathological result shows TB, coexistence of the diseases should be considered.

The impact of Candida spp airway colonization on clinical outcomes in patients with ventilator-associated pneumonia: A systematic review and meta-analysis.

BACKGROUND: Previous studies have drawn different conclusions about the impact of Candida airway colonization on clinical outcomes in patients with ventilator-associated pneumonia (VAP). METHODS: We searched PubMed, the Cochrane Library, Embase (via OVID), and Web of Science database. We included both retrospective and prospective observational studies. The mean difference (MD) or risk ratio (RR) with 95% confidence intervals (CI) were applied to assess the association between Candida colonization and clinical outcomes. RESULTS: A total of 8 studies with 1,661 patients were pooled in our final studies. Compared with patients with VAP without Candida colonization, patients with Candida colonization had significantly longer durations of mechanical ventilation (MD, 1.93; 95% CI, 0.53-3.33). The intensive care unit (ICU) length of stay seems to be longer among Candida colonized patients than noncolonized patients, although the results were not so significant (MD, 1.15; 95% CI, -1.04 to 3.34). Patients with colonization had higher 28-day mortality and ICU mortality than those without colonization (28-day mortality: RR, 1.64; 95% CI, 1.27-2.12; ICU mortality: RR, 1.57; 95% CI, 1.26-1.94). CONCLUSIONS: The presence of Candida spp airway colonization is associated with longer durations of mechanical ventilation, higher 28-day mortality, higher ICU mortality, and probably longer ICU length of stay compared with the absence of colonization in patients with VAP.

Structural and Mechanistic Analyses Reveal a Unique Cas4-like Protein in the Mimivirus Virophage Resistance Element System.

A clustered regularly interspaced short palindromic repeats (CRISPR)-like "mimivirus virophage resistance element" (MIMIVIRE) system, which contains specific cascade genes and a CRISPR array against virophages, was reported in mimiviruses. An essential component of the MIMIVIRE system is R354, encoding a nuclease and a likely functional homolog of Cas4. Here we show that R354 is a dual nuclease with both exonuclease and endonuclease activities. Structural analysis revealed that the catalytic core domain of R354 is similar to those of Cas4 and ? exonuclease despite their low sequence identity. R354 forms a homodimer that is important for its exonuclease but not endonuclease activity. Structural comparisons between the active and semi-active states of R354 demonstrated that an activation loop adjacent to the catalytic site is critical for enzymatic activity. Overall, the results suggest that R354 belongs to a novel MIMIVIRE system involved in innate virus immunity and provides a template for the identification of new CRISPR systems in other species.

Crystallization and structure analysis of the core motif of the Pks13 acyltransferase domain from Mycobacterium tuberculosis.

Type I polyketide synthase 13 (Pks13) is involved in the final step of the biosynthesis of mycolic acid in Mycobacterium tuberculosis. Recent articles have reported that Pks13 is an essential enzyme in the mycolic acid biosynthesis pathway, and it has been deeply studied as a drug target in Tuberculosis. We report a high-resolution structure of the acyltransferase (AT) domain of Pks13 at 2.59 Å resolution. Structural comparison with the full-length AT domain (PDB code, 3TZW, and 3TZZ) reveals a different orientation of the C-terminal helix and rearrangement of some conserved residues.