Electron transfer (ET) reactions within proteins are accomplished by a broad set of redox-active molecules, including natural amino acids. Tryptophan participates in ET chemistry as both a cation and ...a neutral radical. Identification and characterization of the biologically relevant species is essential to understand efficient ET mechanisms in proteins. We present resonance Raman spectra and excitation profiles of the tryptophan cation radical generated by combining a strong oxidant, Ce(IV), with tryptophan model compounds in a fast-flow mixing device. Isotopically modified derivatives, coupled with calculations, allowed the assignment of the normal modes of this radical. Raman bands that are sensitive to protonation state and hydrogen bonding environment of the cation radical were identified. The present findings, along with resonance Raman spectra of the closed-shell and neutral radical counterparts, form a foundation for probing tryptophan-mediated ET reactions in proteins.
Ubiquinol cytochrome c reductase binding protein (UQCRB) is known to play crucial roles in the development of various types of diseases. However, the link between UQCRB and microRNAs remains unknown. ...In the present study, we performed microRNA sequencing of mutant UQCRB-expressing stable cell lines that exhibited pro-oncogenic activities caused by expression of the mutant UQCRB gene. Results showed that hsa-miR-10a-5p was significantly downregulated in the mutant UQCRB-expressing cell lines. Furthermore, mRNA sequencing and gene ontology analysis of differentially expressed genes (DEGs) revealed that the cholesterol biosynthesis pathway might be activation by mutant UQCRB expression. Moreover, inhibition of cholesterol synthesis in mutant UQCRB-expressing cells via treatment with the specific inhibitors suppressed the cell proliferation. Transfection with a hsa-miR-10a-5p mimic validated that lanosterol synthase (LSS) is a target of hsa-miR-10a-5p. In addition, hsa-miR-10a-5p was found to be downregulated in liver cancer cell lines overexpressing UQCRB. Taken together, our findings highlighted the potential use of hsa-miR-10a-5p as a biomarker for UQCRB related diseases.
Isotopologues are valuable vibrational probes that shift features in a vibrational spectrum while preserving the electronic structure of the molecule. We report the vibrational and electronic spectra ...of perdeuterated tryptophan in solution (l-Trp-d 5), as Trp48-d 5 in azurin, and as the photogenerated neutral tryptophan radical, Trp48-d 5 •, in azurin. The UV resonance Raman bands of the perdeuterated closed-shell tryptophan in solution and in azurin are lower in frequency relative to the protiated counterpart. The observed decrease in frequencies of l-Trp-d 5 bands relative to l-Trp-h 5 enables the analysis of vibrational markers of other amino acids, e.g., phenylalanine, that overlap with some modes of l-Trp-h 5. The Raman intensities vary between l-Trp-d 5 and l-Trp-h 5; these differences likely reflect modifications in normal mode composition upon perdeuteration. Analysis of the W3, W6, and W17 modes suggests that the W3 mode retains its utility as a conformational marker; however, the H-bond markers W6 and W17 appear to be less sensitive upon perdeuteration. The neutral tryptophan radical, Trp48-d 5 •, was generated in azurin with a slightly lower radical quantum yield than for Trp48-h 5 •. The visible resonance Raman spectrum of Trp48-d 5 • is different from that of Trp48-h 5 •, especially in terms of relative intensities, and all assignable peaks decreased in frequency upon perdeuteration. The absorption and emission spectra of the perdeuterated closed-shell and radical species exhibited hypsochromic shifts of less than 1 nm relative to the protiated species. The data presented here indicate that l-Trp-d 5 is a valuable probe of vibrational structure, with minimal modification of photoreactivity and photophysics compared to l-Trp-h 5.
Redox-active tryptophans are important in biological electron transfer and redox biochemistry. Proteins can tune the electron transfer kinetics and redox potentials of tryptophan via control of the ...protonation state and the hydrogen-bond strength. We examine the local environment of two neutral tryptophan radicals (Trp108 on the solvent-exposed surface and Trp48 buried in the hydrophobic core) in two azurin variants. Ultrahigh-field EPR spectroscopy at 700 GHz and 25 T allowed complete resolution of all of the principal components of the g tensors of the two radicals and revealed significant differences in the g tensor anisotropies. The spectra together with 2H ENDOR spectra and supporting DFT calculations show that the g tensor anisotropy is directly diagnostic of the presence or absence as well as the strength of a hydrogen bond to the indole nitrogen. The approach is a powerful one for identifying and characterizing hydrogen bonds that are critical in the regulation of tryptophan-assisted electron transfer and tryptophan-mediated redox chemistry in proteins.
Neonatal cardiogenic shock most commonly occurs due to critical congenital heart disease, sepsis, metabolic disorder or arrhythmias. In particular, enterovirus infections are common in the neonatal ...period, and patients can present with fulminant myocarditis. Early recognition is imperative due to its high morbidity and mortality without prompt and aggressive treatment. We present the successful treatment of fulminant neonatal enteroviral myocarditis in a pair of monochorionic diamniotic twins with cardiopulmonary support, intravenous immunoglobulin and pocapavir, an enteroviral capsid inhibitor. The twins took an almost exact parallel hospital course, including day of extracorporeal membrane oxygenation (ECMO) cannulation, day of ECMO decannulation, improvement of cardiac function, discharge and status at follow-up. While it was difficult to assess the relative contribution of each intervention, our case shows promise in the use of pocapavir for treatment of severe enteroviral infections. Remarkably, both twins demonstrated remarkable recovery within 2 weeks, underscoring that early aggressive cardiopulmonary support, and potentially pocapavir, contributed to their recovery.
High-risk human papillomaviruses (HPVs) are involved in the development of several human cancers, including oropharyngeal squamous cell carcinomas. However, many studies have demonstrated that HPV ...alone is not sufficient for the oncogenic transformation of normal human epithelial cells, indicating that additional cofactors are required for the oncogenic conversion of HPV-infected cells. Inasmuch as chronic inflammation is also closely associated with carcinogenesis, we investigated the effect of chronic exposure to tumor necrosis factor α (TNFα), the major proinflammatory cytokine, on oncogenesis in two immortalized oral keratinocyte cell lines, namely, HPV16-immortalized and human telomerase reverse transcriptase (hTERT)-immortalized cells. TNFα treatment led to the acquisition of malignant growth properties in HPV16-immortalized cells, such as (1) calcium resistance, (2) anchorage independence, and (3) increased cell proliferation in vivo. Moreover, TNFα increased the cancer stem cell-like population and stemness phenotype in HPV16-immortalized cells. However, such transforming effects were not observed in hTERT-immortalized cells, suggesting an HPV-specific role in TNFα-promoted oncogenesis. We also generated hTERT-immortalized cells that express HPV16 E6 and E7. Chronic TNFα exposure successfully induced the malignant growth and stemness phenotype in the E6-expressing cells but not in the control and E7-expressing cells. We further demonstrated that HPV16 E6 played a key role in TNFα-induced cancer stemness via suppression of the stemness-inhibiting microRNAs miR-203 and miR-200c. Overexpression of miR-203 and miR-200c suppressed cancer stemness in TNFα-treated HPV16-immortalized cells. Overall, our study suggests that chronic inflammation promotes cancer stemness in HPV-infected cells, thereby promoting HPV-associated oral carcinogenesis.
ABSTRACTTraumatic abrasions on human extremities as a result of direct contact with sea, lake, river, or aquarium animals or from traumatic injuries sustained in seawater may develop into solitary or ...linear granulomatous lesions. One of the more common microbial etiologies for such infections is Mycobacterium marinum. An astute pediatrician, family physician, or nurse practitioner should have a high index of suspicion and obtain specific cultures to support the growth of Mycobacterium species. Mycobacterium marinum infections will not respond to antibiotics typically chosen to treat simple skin and soft tissue infections. Rather, M. marinum infections are best treated by prolonged antimicrobial treatment regimens for 3 to 6 months and, in some cases, may require polypharmacologic therapy. We present the case of a 6-year-old girl who suffered a traumatic abrasion on her right ankle in seawater. For 10 days, the skin infection morphed from cellulitis, papules, pustules, and eventually into sporotrichoid linear granuloma. After several failed antibiotic trials, M. marinum was eventually identified from the depth of her lesions. The patient improved after a 3-month course of clarithromycin. This case report is the first to include pictures demonstrating the clinical progression and resolution of M. marinum infection.
The Korea – United States Air Quality Study (May – June 2016) deployed instrumented aircraft and ground-based measurements to elucidate causes of poor air quality related to high ozone and aerosol ...concentrations in South Korea. This work synthesizes data pertaining to aerosols (specifically, particulate matter with aerodynamic diameters <2.5 micrometers, PM2.5) and conditions leading to violations of South Korean air quality standards (24-hr mean PM2.5 < 35 µg m–3). PM2.5 variability from AirKorea monitors across South Korea is evaluated. Detailed data from the Seoul vicinity are used to interpret factors that contribute to elevated PM2.5. The interplay between meteorology and surface aerosols, contrasting synoptic-scale behavior vs. local influences, is presented. Transboundary transport from upwind sources, vertical mixing and containment of aerosols, and local production of secondary aerosols are discussed. Two meteorological periods are probed for drivers of elevated PM2.5. Clear, dry conditions, with limited transport (Stagnant period), promoted photochemical production of secondary organic aerosol from locally emitted precursors. Cloudy humid conditions fostered rapid heterogeneous secondary inorganic aerosol production from local and transported emissions (Transport/Haze period), likely driven by a positive feedback mechanism where water uptake by aerosols increased gas-to-particle partitioning that increased water uptake. Further, clouds reduced solar insolation, suppressing mixing, exacerbating PM2.5 accumulation in a shallow boundary layer. The combination of factors contributing to enhanced PM2.5 is challenging to model, complicating quantification of contributions to PM2.5 from local versus upwind precursors and production. We recommend co-locating additional continuous measurements at a few AirKorea sites across South Korea to help resolve this and other outstanding questions: carbon monoxide/carbon dioxide (transboundary transport tracer), boundary layer height (surface PM2.5 mixing depth), and aerosol composition with aerosol liquid water (meteorologically-dependent secondary production). These data would aid future research to refine emissions targets to further improve South Korean PM2.5 air quality.
Congenital systemic-to-pulmonary collateral arteries or major aortopulmonary collaterals are associated with cyanotic congenital heart disease with decreased pulmonary blood flow. Though it is ...usually associated with congenital heart diseases, there is an increased incidence of isolated acquired aortopulmonary collaterals in premature infants with chronic lung disease. Interestingly, isolated congenital aortopulmonary collaterals can occur without any lung disease, which may cause congestive heart failure and require closure. We present a neonate with an echocardiogram that showed only left-sided heart dilation. Further workup with a CT angiogram demonstrated an anomalous systemic artery from the descending thoracic aorta supplying the left lower lobe. He eventually developed heart failure symptoms and was taken to the catheterization laboratory for closure of the collateral. However, with the collateral being the only source of blood flow to the entire left lower lobe, he required surgical unifocalization. Isolated aortopulmonary collaterals without any other congenital heart disease or lung disease are rare. Our patient is the first reported case to have an isolated aortopulmonary collateral being the sole pulmonary blood supply to an entire lung segment. Due to its rarity, there is still much to learn about the origin and development of these collaterals that possibly developed prenatally.
Tryptophan radicals play a significant role in mediating biological electron transfer and catalytic processes. Here, we employ visible and UV resonance Raman, EPR, and absorption spectroscopy along ...with pH/isotope studies and calculations to probe a neutral closed-shell tryptophan and its oxidized radical counterpart in a modified azurin protein. Comparison of the resonance Raman spectra of the radical and closed-shell species combined with vibrational analysis reveals important structural differences between these two tryptophan species. We experimentally observe a significant reduction in bond order of the pyrrole ring of the radical, as evidenced by a 208 cm−1 downshift of the W3 mode (predominantly C2−C3 stretch). Analysis of the spectra acquired at acidic pH and in deuterated buffer highlights those vibrational modes of the radical that are sensitive to the hydrogen-bonding environment. The most significant change caused by the deuterated buffer is a 45 cm−1 downshift of an indole nitrogen displacement mode (W17). Our spectra provide evidence that the radical species is a strong hydrogen bond acceptor, particularly in an acidic environment. Furthermore, the pK a for this tryptophan radical must be less than 4.0, which falls below previously reported values for l-tryptophan in aqueous solution. The normal mode assignments of the tryptophan radical help characterize its local environment, conformation, hydrogen bonding, and protonation state within a protein.
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