Special Considerations in Pediatric Endoscopic Skull Base Surgery.

Originally pioneered in adults, endoscopic endonasal approaches for skull base pathology are being increasingly applied as a minimally invasive alternative for young children. Intrinsic anatomic differences between these patient populations have sparked discussions on the feasibility, safety, and efficacy of these techniques in pediatric patients. This work aims to serve as a primer for clinicians engaged in the rapidly evolving field of pediatric endoscopic skull base surgery. A succinct overview of relevant embryology, sinonasal anatomy, and diagnostic workup is presented to emphasize key differences and unique technical considerations. Additional discussions regarding select skull base lesions, reconstructive paradigms, potential surgical complications, and postoperative care are also highlighted in the setting of multidisciplinary teams.

Hypoglossal Nerve Stimulator in the Active Duty Population: Military Readiness and Satisfaction.

INTRODUCTION: Because inadequate sleep impairs mission performance, the U.S. Army regards sleep as a core pillar of soldier readiness. There is an increasing incidence of obstructive sleep apnea (OSA) among active duty (AD) service members, which is a disqualifying condition for initial enlistment. Moreover, a new diagnosis of OSA in the AD population often prompts a medical evaluation board, and if symptomatic OSA proves refractory to treatment, this may result in medical retirement. Hypoglossal nerve stimulator implantation (HNSI) is a newer implantable treatment option, which requires minimal ancillary equipment to function and may provide a useful treatment modality to support AD service members while maintaining readiness in appropriate candidates. Because of a perception among AD service members that HNSI results in mandatory medical discharge, we aimed to evaluate the impact of HNSI on military career progression, maintenance of deployment readiness, and patient satisfaction. METHODS: The Department of Research Programs at the Walter Reed National Military Medical Center provided institutional review board approval for this project. This is a retrospective, observational study and telephonic survey of AD HNSI recipients. Military service information, demographics, surgical data, and postoperative sleep study results were collected from each patient.Additional survey questions assessed each service member's experience with the device. RESULTS: Fifteen AD service members who underwent HNSI between 2016 and 2021 were identified. Thirteen subjects completed the survey. The mean age was 44.8 years (range 33-61), and all were men. Six subjects (46%) were officers. All subjects maintained AD status following HNSI yielding 14.5 person-years of continued AD service with the implant. One subject underwent formal assessment for medical retention. One subject transferred from a combat role to a support role. Six subjects have since voluntarily separated from AD service following HNSI. These subjects spent an average of 360 (37-1,039) days on AD service. Seven subjects currently remain on AD and have served for an average of 441 (243-882) days. Two subjects deployed following HNSI. Two subjects felt that HSNI negatively affected their career. Ten subjects would recommend HSNI to other AD personnel. Following HNSI, of the eight subjects with postoperative sleep study data, five achieved surgical success defined as >50% reduction of apnea-hypopnea index and absolute apnea-hypopnea index value of <20. CONCLUSIONS: Hypoglossal nerve stimulator implantation for AD service members offers an effective treatment modality for OSA, which generally allows for the ability to maintain AD status, however: The impact on deployment readiness should be seriously considered and tailored to each service member based on their unique duties before implantation. Seventy-seven percent of HNSI patients would recommend it to other AD service members suffering from OSA.

A radioactive CRISPR interference system using 89Zr-labeled LbCas12a.

Recently, CRISPR proteins have been recognized as promising candidates for drug development. However, there is still a lack of substances with the appropriate sensitivity and stability for targeted drug delivery systems. 89Zr is a radioactive isotope that emits positrons, allowing real-time in vivo tracking with proven safety. In this study, we confirmed that labeling with 89Zr did not compromise the functionality of CRISPR proteins during in vivo behavioral imaging. Furthermore, we demonstrated the therapeutic efficacy of the CRISPR interference system in a mouse model of liver fibrosis, highlighting the theragnostic potential of isotope-labeled CRISPR proteins. The findings of this research could contribute to various aspects of ongoing clinical studies exploring the in vivo applications of CRISPR proteins.

Cranioplasty in the deployed environment: experience for host-country nationals.

OBJECTIVE: Decompressive craniectomy (DC) is the definitive neurosurgical treatment for managing refractory malignant cerebral edema and intracranial hypertension due to combat-related severe traumatic brain injury (TBI). To date, the long-term outcomes and sequelae of this procedure on host-country national (HCN) populations during Operation Iraqi Freedom (Iraq, 2003-2011), Operation Enduring Freedom (Afghanistan, 2001-2014), and Operation Freedom's Sentinel (Afghanistan, 2015-2021) have not been described, specifically the process and results of delayed custom synthetic cranioplasty. The Joint Trauma System's Clinical Practice Guidelines (JTS-CPG) for severe head injury counsels surgeons to discard the cranial osseous explant when treating coalition service members. Ongoing political and healthcare system instabilities often preclude opportunities for delayed cranioplasty by host-country assets. Various surgical options (such as hinge craniectomy) are inadequate in the setting of complicated cranial comminution from blast or missile injuries, severe cerebral edema, grossly contaminated wounds, complex polytrauma, and tissue devitalization. Delayed cranioplasty with a custom synthetic implant is a viable but logistically challenging alternative. In this retrospective review, the authors present the first patient series describing delayed custom synthetic cranioplasty in an HCN population performed during active military conflict. METHODS: Patients were identified through the Joint Trauma System/Theater Medical Data Store, and subgroup analyses were performed to include mechanisms of injury, surgical complications, and clinical outcomes. RESULTS: Twenty-five patients underwent DC between 2012 and 2020 to treat penetrating, blast, and high-energy closed head injuries per JTS-CPG criteria. The average time from injury to surgery was 1.4 days, although 6 patients received delayed care (3-6 days) due to protracted evacuation from local hospitals. Delayed care correlated with an increased rate of intracranial abscess and empyema. The average time to cranioplasty was 134 days due to a lack of robust mechanisms for patient follow-up, tracking, and access to NATO hospitals. HCN patients who recovered from DC demonstrated overall benefit from custom synthetic cranioplasty, although formal statistical analysis was impeded by a lack of long-term follow-up. CONCLUSIONS: This review demonstrates that cranioplasty with a custom synthetic implant is a safe and feasible treatment for vulnerable HCN patients who survive their index DC surgery. This unique paradigm of care highlights the capabilities of deployed neurosurgical healthcare teams working in partnership with the prosthetics laboratory at Walter Reed National Military Medical Center.

Splicing factor SRSF3 represses translation of p21cip1/waf1 mRNA.

Serine/arginine-rich splicing factor 3 (SRSF3) is an RNA binding protein that most often regulates gene expression at the splicing level. Although the role of SRSF3 in mRNA splicing in the nucleus is well known, its splicing-independent role outside of the nucleus is poorly understood. Here, we found that SRSF3 exerts a translational control of p21 mRNA. Depletion of SRSF3 induces cellular senescence and increases the expression of p21 independent of p53. Consistent with the expression patterns of SRSF3 and p21 mRNA in the TCGA database, SRSF3 knockdown increases the p21 mRNA level and its translation efficiency as well. SRSF3 physically associates with the 3'UTR region of p21 mRNA and the translational initiation factor, eIF4A1. Our study proposes a model in which SRSF3 regulates translation by interacting with eIF4A1 at the 3'UTR region of p21 mRNA. We also found that SRSF3 localizes to the cytoplasmic RNA granule along with eIF4A1, which may assist in translational repression therein. Thus, our results provide a new mode of regulation for p21 expression, a crucial regulator of the cell cycle and senescence, which occurs at the translational level and involves SRSF3.

Interactions between EGFR and EphA2 promote tumorigenesis through the action of Ephexin1.

The cell signaling factors EGFR, EphA2, and Ephexin1 are associated with lung and colorectal cancer and play an important role in tumorigenesis. Although the respective functional roles of EGFR and EphA2 are well known, interactions between these proteins and a functional role for the complex is not understood. Here, we showed that Ephexin1, EphA2, and EGFR are each expressed at higher levels in lung and colorectal cancer patient tissues, and binding of EGFR to EphA2 was associated with both increased tumor grade and metastatic cases in both cancer types. Treatment with Epidermal Growth Factor (EGF) induced binding of the RR domain of EGFR to the kinase domain of EphA2, and this binding was promoted by Ephexin1. Additionally, the AKT-mediated phosphorylation of EphA2 (at Ser897) promoted interactions with EGFR, pointing to the importance of this pathway. Two mutations in EGFR, L858R and T790M, that are frequently observed in lung cancer patients, promoted binding to EphA2, and this binding was dependent on Ephexin1. Our results indicate that the formation of a complex between EGFR, EphA2, and Ephexin1 plays an important role in lung and colorectal cancers, and that inhibition of this complex may be an effective target for cancer therapy.

SCARA3 inhibits cell proliferation and EMT through AKT signaling pathway in lung cancer.

BACKGROUND: Scavenger receptor class A member 3 (SCARA3) is decreased in prostate cancer and myeloma. However, functions of SCARA3 in various cancers remain unclear. In this study, we tried to evaluate the functional study of SCARA3 in lung cancer. METHODS: The expression level of SCARA3 in the TCGA-database, lung cancer tissue microarray and lung cancer cells and the prognosis of lung cancer patients were measured. Lung cancer tissue microarray was analyzed pathologically using immunohistochemistry, and quantitative analysis of SCARA3 in normal lung cells and lung cancer cells was analyzed using western blot analysis. Survival curves for lung cancer patients were prepared with the Kaplan-Meier method. Migration and invasion of SCARA3 overexpressed lung cancer cells were determined using a Transwell chamber system. Proliferation of lung cancer cells was determined based on cell viability assay using cell culture in vitro and a tumorigenicity model of BALB/C nude mouse in vivo. RESULTS: The expression of SCARA3 was abnormally reduced in TCGA-database, lung tissue microarray, and various lung cancer cells. However, overexpression of SCARA3 reduced the proliferation of lung cancer. The ability of SCARA3 to inhibit cancer cell proliferation was maintained even in vivo using a mouse xenograft model. In addition, overexpression of SCARA3 reduced migration and invasion ability of lung cancer cells and induced decreases of EMT markers such as ß-catenin, vimentin, and MMP9. We aimed to prove the role of SCARA3 in the treatment of Lung cancer, and shown that the expression level of SCARA3 is important in cancer treatment using cisplatin. The enhancement of the effect of cisplatin according to SCARA3 overexpression is via the AKT and JNK pathways. CONCLUSIONS: This study confirmed an abnormal decrease in SCARA3 in lung cancer. Overexpression of SCARA3 potently inhibited tumors in lung cancer and induced apoptosis by increasing sensitivity of lung cancer to cisplatin. These results suggest that SCARA3 is a major biomarker of lung cancer and that the induction of SCARA3 overexpression can indicate an effective treatment.

HspBP1 is a dual function regulatory protein that controls both DNA repair and apoptosis in breast cancer cells.

The Hsp70-binding protein 1 (HspBP1) belongs to a family of co-chaperones that regulate Hsp70 activity and whose biological significance is not well understood. In the present study, we show that when HspBP1 is either knocked down or overexpressed in BRCA1-proficient breast cancer cells, there were profound changes in tumorigenesis, including anchorage-independent cell growth in vitro and in tumor formation in xenograft models. However, HspBP1 did not affect tumorigenic properties in BRCA1-deficient breast cancer cells. The mechanisms underlying HspBP1-induced tumor suppression were found to include interactions with BRCA1 and promotion of BRCA1-mediated homologous recombination DNA repair, suggesting that HspBP1 contributes to the suppression of breast cancer by regulating BRCA1 function and thereby maintaining genomic stability. Interestingly, independent of BRCA1 status, HspBP1 facilitates cell survival in response to ionizing radiation (IR) by interfering with the association of Hsp70 and apoptotic protease-activating factor-1. These findings suggest that decreased HspBP1 expression, a common occurrence in high-grade and metastatic breast cancers, leads to genomic instability and enables resistance to IR treatment.

Akt-mediated Ephexin1-Ras interaction promotes oncogenic Ras signaling and colorectal and lung cancer cell proliferation.

ABSTRCT: Ephexin1 was reported to be highly upregulated by oncogenic Ras, but the functional consequences of this remain poorly understood. Here, we show that Ephexin1 is highly expressed in colorectal cancer (CRC) and lung cancer (LC) patient tissues. Knockdown of Ephexin1 markedly inhibited the cell growth of CRC and LC cells with oncogenic Ras mutations. Ephexin1 contributes to the positive regulation of Ras-mediated downstream target genes and promotes Ras-induced skin tumorigenesis. Mechanically, Akt phosphorylates Ephexin1 at Ser16 and Ser18 (pSer16/18) and pSer16/18 Ephexin1 then interacts with oncogenic K-Ras to promote downstream MAPK signaling, facilitating tumorigenesis. Furthermore, pSer16/18 Ephexin1 is associated with both an increased tumor grade and metastatic cases of CRC and LC, and those that highly express pSer16/18 exhibit poor overall survival rates. These data indicate that Ephexin1 plays a critical role in the Ras-mediated CRC and LC and pSer16/18 Ephexin1 might be an effective therapeutic target for CRC and LC.

Somatic cell hemoglobin modulates nitrogen oxide metabolism in the human airway epithelium.

Endothelial hemoglobin (Hb)α regulates endothelial nitric oxide synthase (eNOS) biochemistry. We hypothesized that Hb could also be expressed and biochemically active in the ciliated human airway epithelium. Primary human airway epithelial cells, cultured at air-liquid interface (ALI), were obtained by clinical airway brushings or from explanted lungs. Human airway Hb mRNA data were from publically available databases; or from RT-PCR. Hb proteins were identified by immunoprecipitation, immunoblot, immunohistochemistry, immunofluorescence and liquid chromatography- mass spectrometry. Viral vectors were used to alter Hbß expression. Heme and nitrogen oxides were measured colorimetrically. Hb mRNA was expressed in human ciliated epithelial cells. Heme proteins (Hbα, ß, and δ) were detected in ALI cultures by several methods. Higher levels of airway epithelial Hbß gene expression were associated with lower FEV1 in asthma. Both Hbß knockdown and overexpression affected cell morphology. Hbß and eNOS were apically colocalized. Binding heme with CO decreased extracellular accumulation of nitrogen oxides. Human airway epithelial cells express Hb. Higher levels of Hbß gene expression were associated with airflow obstruction. Hbß and eNOS were colocalized in ciliated cells, and heme affected oxidation of the NOS product. Epithelial Hb expression may be relevant to human airways diseases.

MeCP2 regulates gene expression through recognition of H3K27me3.

MeCP2 plays a multifaceted role in gene expression regulation and chromatin organization. Interaction between MeCP2 and methylated DNA in the regulation of gene expression is well established. However, the widespread distribution of MeCP2 suggests it has additional interactions with chromatin. Here we demonstrate, by both biochemical and genomic analyses, that MeCP2 directly interacts with nucleosomes and its genomic distribution correlates with that of H3K27me3. In particular, the methyl-CpG-binding domain of MeCP2 shows preferential interactions with H3K27me3. We further observe that the impact of MeCP2 on transcriptional changes correlates with histone post-translational modification patterns. Our findings indicate that MeCP2 interacts with genomic loci via binding to DNA as well as histones, and that interaction between MeCP2 and histone proteins plays a key role in gene expression regulation.

Secondhand smoke alters arachidonic acid metabolism and inflammation in infants and children with cystic fibrosis.

BACKGROUND: Mechanisms that facilitate early infection and inflammation in cystic fibrosis (CF) are unclear. We previously demonstrated that children with CF and parental-reported secondhand smoke exposure (SHSe) have increased susceptibility to bacterial infections. SHSe hinders arachidonic acid (AA) metabolites that mediate immune function in patients without CF, and may influence CF immune dysfunction. We aimed to define SHSe's impact on inflammation mediators and infection in children with CF. METHODS: Seventy-seven children with CF <10 years of age (35 infants <1 year; 42 children 1-10 years) were enrolled and hair nicotine concentrations measured as an objective surrogate of SHSe. AA signalling by serum and macrophage lipidomics, inflammation using blood transcriptional profiles and in vitro macrophage responses to bacterial infection after SHSe were assessed. RESULTS: Hair nicotine concentrations were elevated in 63% of patients. Of the AA metabolites measured by plasma lipidomics, prostaglandin D2 (PGD2) concentrations were decreased in children with CF exposed to SHSe, and associated with more frequent hospitalisations (p=0.007) and worsened weight z scores (p=0.008). Children with CF exposed to SHSe demonstrated decreased expression of the prostaglandin genes PTGES3 and PTGR2 and overexpression of inflammatory pathways. These findings were confirmed using an in vitro model, where SHSe was associated with a dose-dependent decrease in PGD2 and increased methicillin-resistant Staphylococcus aureus survival in human CF macrophages. CONCLUSIONS: Infants and young children with CF and SHSe have altered AA metabolism and dysregulated inflammatory gene expression resulting in impaired bacterial clearance. Our findings identified potential therapeutic targets to halt early disease progression associated with SHSe in the young population with CF.

C2-C3 Anterior Cervical Arthrodesis in the Treatment of Bow Hunter's Syndrome: Case Report and Review of the Literature.

BACKGROUND: Bow hunter's syndrome (BHS) or rotational vertebral artery occlusion is a rare syndrome of vertebrobasilar insufficiency due to compression or occlusion of the contralateral vertebral artery with cervical axial rotation. Compression at the C2-C3 level, the junction between the axial and subaxial spine, has not been described. Management can include medical treatment with antiplatelet medications, surgical fusion, or vertebral artery decompression. CASE DESCRIPTION: The patient presented with dizziness and loss of consciousness with axial head rotation to the left. Dynamic digital subtraction angiography revealed occlusion of the right vertebral artery with the head turning to the left, with concurrent symptom onset. The left vertebral artery largely ended in the posterior inferior cerebellar artery. The patient underwent C2-C3 anterior cervical discectomy and fusion without vertebral artery decompression. His postoperative course was uneventful, with complete symptom resolution. Follow-up dynamic angiography demonstrated a patent right vertebral artery with axial head rotation to the left. CONCLUSIONS: This case report demonstrates that even high cervical etiology for BHS can be successfully managed from an anterior approach. At present, no consensus has been reached for the treatment of BHS. A review of the current data demonstrated that anterior approaches without decompression are slightly safer than posterior approaches, with a smaller risk of vertebral artery injury. Depending on the anatomic variant and the pathophysiology of vertebral compression, an anterior approach without decompression provides a feasible alternative for the treatment of symptomatic BHS.

The oncogenic effects of p53-inducible gene 3 (PIG3) in colon cancer cells.

The p53-inducible gene 3 (PIG3), initially identified as a gene downstream of p53, plays an important role in the apoptotic process triggered by p53-mediated reactive oxygen species (ROS) production. Recently, several studies have suggested that PIG3 may play a role in various types of cancer. However, the functional significance of PIG3 in cancer remains unclear. Here, we found that PIG3 was highly expressed in human colon cancer cell lines compared to normal colonderived fibroblasts. Therefore, we attempted to elucidate the functional role of PIG3 in colon cancer. PIG3 overexpression increases the colony formation, migration and invasion ability of HCT116 colon cancer cells. Conversely, these tumorigenic abilities were significantly decreased in in vitro studies with PIG3 knockdown HCT116 cells. PIG3 knockdown also attenuated the growth of mouse xenograft tumors. These results demonstrate that PIG3 is associated with the tumorigenic potential of cancer cells, both in vitro and in vivo, and could play a key oncogenic role in colon cancer.

Silymarin Inhibits Cytokine-Stimulated Pancreatic Beta Cells by Blocking the ERK1/2 Pathway.

We show that silymarin, a polyphenolic flavonoid isolated from milk thistle (Silybum marianum), inhibits cytokine mixture (CM: TNF-α, IFN-γ, and IL-1ß)-induced production of nitric oxide (NO) in the pancreatic beta cell line MIN6N8a. Immunostaining and Western blot analysis showed that silymarin inhibits iNOS gene expression. RT-PCR showed that silymarin inhibits iNOS gene expression in a dose-dependent manner. We also showed that silymarin inhibits extracellular signal-regulated protein kinase-1 and 2 (ERK1/2) phosphorylation. A MEK1 inhibitor abrogated CM-induced nitrite production, similar to silymarin. Treatment of MIN6N8a cells with silymarin also inhibited CM-stimulated activation of NF-κB, which is important for iNOS transcription. Collectively, we demonstrate that silymarin inhibits NO production in pancreatic beta cells, and silymarin may represent a useful anti-diabetic agent.

Reverse genetics with a full-length infectious cDNA of the Middle East respiratory syndrome coronavirus.

Severe acute respiratory syndrome with high mortality rates (~50%) is associated with a novel group 2c betacoronavirus designated Middle East respiratory syndrome coronavirus (MERS-CoV). We synthesized a panel of contiguous cDNAs that spanned the entire genome. Following contig assembly into genome-length cDNA, transfected full-length transcripts recovered several recombinant viruses (rMERS-CoV) that contained the expected marker mutations inserted into the component clones. Because the wild-type MERS-CoV contains a tissue culture-adapted T1015N mutation in the S glycoprotein, rMERS-CoV replicated ~0.5 log less efficiently than wild-type virus. In addition, we ablated expression of the accessory protein ORF5 (rMERS•ORF5) and replaced it with tomato red fluorescent protein (rMERS-RFP) or deleted the entire ORF3, 4, and 5 accessory cluster (rMERS-ΔORF3-5). Recombinant rMERS-CoV, rMERS-CoV•ORF5, and MERS-CoV-RFP replicated to high titers, whereas MERS-ΔORF3-5 showed 1-1.5 logs reduced titer compared with rMERS-CoV. Northern blot analyses confirmed the associated molecular changes in the recombinant viruses, and sequence analysis demonstrated that RFP was expressed from the appropriate consensus sequence AACGAA. We further show dipeptidyl peptidase 4 expression, MERS-CoV replication, and RNA and protein synthesis in human airway epithelial cell cultures, primary lung fibroblasts, primary lung microvascular endothelial cells, and primary alveolar type II pneumocytes, demonstrating a much broader tissue tropism than severe acute respiratory syndrome coronavirus. The availability of a MERS-CoV molecular clone, as well as recombinant viruses expressing indicator proteins, will allow for high-throughput testing of therapeutic compounds and provide a genetic platform for studying gene function and the rational design of live virus vaccines.

Regulation of cellular RNA nano-particle assembly by splicing factor SRp20.

Cellular RNA nano-particles (RNA granules) such as stress granule (SG) and P-body (PB) are translationally silenced mRNA-protein complexes. Previously, a genome-wide loss-of-function screen using oligomeric siRNAs targeting potential drug target genes was performed to identify genes that are involved in SG and PB assembly. SRp20 (SRSF3), a splicing regulator, was identified as a potential regulator for the RNA granule assembly. Here, we show that SRp20 is a bona-fide RNA granule component using antibody against SRp20 as well as Flag-tagged SRp20 through immunofluorescence microscopy. More importantly, upon knockdown of SRp20 using siRNA, RNA granule formation was potently disrupted indicating that SRp20 is one of the major structural components of SGs and PBs. Interestingly, polysome profiling analyses displayed that SRp20 is distributed in all ribosomal fractions suggesting a potential role of SRp20 as a post-transcriptional mRNA regulator. These results broaden the functional role of SRp20 from the nuclear RNA processing events to the cytoplasmic post-transcriptional mRNA regulatory events through RNA granules that are critical for the regulation of gene expression.

ß-Catenin and peroxisome proliferator-activated receptor-δ coordinate dynamic chromatin loops for the transcription of vascular endothelial growth factor A gene in colon cancer cells.

Vascular endothelial growth factor A (VEGFA) mRNA is regulated by ß-catenin and peroxisome proliferator activated receptor δ (PPAR-δ) activation in colon cancer cells, but the detailed mechanism remains to be elucidated. As chromatin loops are generally hubs for transcription factors, we tested here whether ß-catenin could modulate chromatin looping near the VEGFA gene and play any important role for PPAR-δ activated VEGFA transcription. First, we identified the far upstream site as an important site for VEGFA transcription by luciferase assay and chromatin immunoprecipitation in colorectal carcinoma HCT116 cells. Chromatin conformation capture analysis also revealed the chromatin loops formed by the ß-catenin bindings on these sites near the VEGFA gene. Dynamic association and dissociation of ß-catenin/TCF-4/PPAR-δ on the far upstream site and ß-catenin/NF-κB p65 on the downstream site were also detected depending on PPAR-δ activation. Interestingly, ß-catenin-mediated chromatin loops were relieved by PPAR-δ activation, suggesting a regulatory role of ß-catenin for VEGFA transcription. Based on these data, we propose a model for PPAR-δ-activated VEGFA transcription that relies on ß-catenin-mediated chromatin looping as a prerequisite for the activation. Our findings could extend to other ß-catenin regulated target genes and could provide a general mechanism and novel paradigm for ß-catenin-mediated oncogenesis.