The miR-23a∼27a∼24-2 microRNA Cluster Promotes Inflammatory Polarization of Macrophages.

Macrophages are critical for regulating inflammatory responses. Environmental signals polarize macrophages to either a proinflammatory (M1) state or an anti-inflammatory (M2) state. We observed that the microRNA (miRNA) cluster mirn23a, coding for miRs-23a, -27a, and -24-2, regulates mouse macrophage polarization. Gene expression analysis of mirn23a-deficient myeloid progenitors revealed a decrease in TLR and IFN signaling. Mirn23a -/- bone marrow-derived macrophages (BMDMs) have an attenuated response to LPS, demonstrating an anti-inflammatory phenotype in mature cells. In vitro, mirn23a-/- BMDMs have decreased M1 responses and an enhanced M2 responses. Overexpression of mirn23a has the opposite effect, enhancing M1 and inhibiting M2 gene expression. Interestingly, expression of mirn23a miRNAs goes down with inflammatory stimulation and up with anti-inflammatory stimulation, suggesting that its regulation prevents locking macrophages into polarized states. M2 polarization of tumor-associated macrophages (TAMs) correlates with poor outcome for many tumors, so to determine if there was a functional consequence of mirn23a loss modulating immune cell polarization, we assayed syngeneic tumor growth in wild-type and mirn23a -/- mice. Consistent with the increased anti-inflammatory/immunosuppressive phenotype in vitro, mirn23a -/- mice inoculated with syngeneic tumor cells had worse outcomes compared with wild-type mice. Coinjecting tumor cells with mirn23a -/- BMDMs into wild-type mice phenocopied tumor growth in mirn23a -/- mice, supporting a critical role for mirn23a miRNAs in macrophage-mediated tumor immunity. Our data demonstrate that mirn23a regulates M1/M2 polarization and suggests that manipulation of mirn23a miRNA can be used to direct macrophage polarization to drive a desired immune response.

Patterns of Osteopontin Expression in Abusive Head Trauma Compared with Other Causes of Pediatric Traumatic Brain Injury.

OBJECTIVE: To examine levels of plasma osteopontin (OPN), a recently described neuroinflammatory biomarker, in children with abusive head trauma (AHT) compared with children with other types of traumatic brain injury (TBI). STUDY DESIGN: The study cohort comprised children aged <4 years diagnosed with TBI and seen in the intensive care unit in a tertiary children's hospital. Patients were classified as having confirmed or suspected AHT or TBI by other mechanisms (eg, motor vehicle accidents), as identified by a Child Protection Team clinician. Serial blood samples were collected at admission and at 24, 48, and 72 hours after admission. Levels of OPN were compared across groups. RESULTS: Of 77 patients identified, 24 had confirmed AHT, 12 had suspected AHT, and 41 had TBI. There were no differences in the Glasgow Coma Scale score between the patients with confirmed AHT and those with suspected AHT and those with TBI (median score, 4.5 vs 4 and 7; P = .39). At admission to the emergency department, OPN levels were significantly higher in children with confirmed AHT compared with the other 2 groups (mean confirmed AHT, 471.5 ng/mL; median suspected AHT, 322.3 ng/mL; mean TBI, 278.0 ng/mL; P = .03). Furthermore, the adjusted mean trajectory levels of OPN were significantly higher in the confirmed AHT group compared with the other 2 groups across all subsequent time points (P = <.01). CONCLUSIONS: OPN is significantly elevated in children with confirmed AHT compared with those with suspected AHT and those with other types of TBI. OPN expression may help identify children with suspected AHT to aid resource stratification and triage of appropriate interventions for children who are potential victims of abuse.

ML327 induces apoptosis and sensitizes Ewing sarcoma cells to TNF-related apoptosis-inducing ligand.

Ewing sarcomas are rare mesenchymal-derived bone and soft tissue tumors in children. Afflicted children with distant metastases have poor survival despite aggressive therapeutics. Epithelial-to-mesenchymal transition in epithelial carcinomas is associated with loss of E-cadherin and resistance to apoptosis. ML327 is a novel small molecule that we have previously shown to reverse epithelial-to-mesenchymal transition features in both epithelial and neural crest-derived cancers. Herein, we sought to evaluate the effects of ML327 on mesenchymal-derived Ewing sarcoma cells, hypothesizing that ML327 initiates growth arrest and sensitizes to TNF-related apoptosis-inducing ligand. ML327 induced protein expression changes, increased E-cadherin and decreased vimentin, consistent with partial induction of mesenchymal-to-epithelial transition in multiple Ewing Sarcoma cell lines (SK-N-MC, TC71, and ES-5838). Induction of epithelial features was associated with apoptosis, as demonstrated by PARP and Caspase 3 cleavage by immunoblotting. Cell cycle analysis validated these findings by marked induction of the subG0 cell population. In vitro combination treatment with TRAIL demonstrated additive induction of apoptotic markers. Taken together, these findings establish a rationale for further in vivo trials of ML327 in cells of mesenchymal origin both alone and in combination with TRAIL.