A dual role of the conserved PEX19 helix in safeguarding peroxisomal membrane proteins.

Accurate localization of membrane proteins is essential for proper cellular functioning and the integrity of cellular membranes. Post-translational targeting of peroxisomal membrane proteins (PMPs) is mediated by the cytosolic chaperone PEX19 and its membrane receptor PEX3. However, the molecular mechanisms underlying PMP targeting are poorly understood. Here, using biochemical and mass spectrometry analysis, we find that a conserved PEX19 helix, αd, is critical to prevent improper exposure of the PEX26 transmembrane domain (TMD) to cytosolic chaperones. Furthermore, the αd helix of PEX19 interacts with the cytosolic domain of the PEX3 receptor, thereby triggering PEX26 release at the correct destination membrane. The peroxisome-deficient PEX3-G138E mutant completely abolishes this secondary interaction, leading to lack of PEX3-induced PEX26 release from PEX19. These findings elucidate a dual molecular mechanism that is essential to membrane protein protection and destination-specific release by a molecular chaperone.

Intraosseous hemangioma with aneurysmal bone cyst-like changes of the hyoid bone: Case report and literature review.

RATIONALE: Intraosseous hemangioma is a rare benign vascular tumor of the bone that can affect any body part; however, the most common site is the vertebra, followed by calvarial bones. PATIENT CONCERNS: We present a case of intraosseous hemangioma in a 23-year-old male who presented a feeling of fullness in the throat for 3 months. The hyoid bone level had a hard mass of about 5 cm. Fine needle aspiration showed 5 mL dark bloody aspirates. Magnetic resonance image showed a 5.3 cm mixed signal intensity lesion in the hyoid body. DIAGNOSIS: Histopathologic examination showed intraosseous hemangioma with aneurysmal bone cyst (ABC)-like changes in the hyoid bone. INTERVENTIONS: The mass was completely removed without significant problems. OUTCOMES: Complete mass excision and symptomatic improvements were achieved, and no subsequent relapses were observed. LESSONS: The authors experienced a case of intraosseous hemangioma with ABC-like changes. There has been no case report of intraosseous hemangioma in the hyoid bone. This case showed a spectral pattern of the ABC-like changes developing from the underlying bone tumor as a secondary change. ABC-like changes in bone tumors can mislead the diagnosis. Careful examination of the tumor is essential for the correct diagnosis of ABC or ABC-like changes.

Anaplastic Transformation in Papillary Thyroid Carcinoma: A Case Report.

Anaplastic thyroid cancer (ATC), a rare thyroid malignancy, accounts for only 5% of all thyroid cancers. However, it is the most aggressive form and has a very poor prognosis. Increasing evidence suggests that ATC arises from papillary thyroid carcinoma (PTC). However, the exact mechanism underlying this transformation remains unclear. In almost all cases, ATC originates within, but rarely outside, the thyroid gland. Transformation of metastatic PTC into ATC within the cervical lymph nodes is extremely rare. In this report, we present a rare case in a 63-year-old male patient who was initially diagnosed with PTC at his first hospital visit, which underwent anaplastic transformation in lymph node metastasis, and was subsequently diagnosed during the follow-up visit.

An Ectopic Parathyroid Adenoma of the Retropharynx in a Patient with Primary Hyperparathyroidism and Papillary Thyroid Cancer-A Rare Case.

The frequency of concurrent thyroid cancer in patients with primary hyperparathyroidism (pHPT) varies. While the pathological association between thyroid and parathyroid disorders is frequently noted, the co-occurrence of parathyroid adenoma and papillary thyroid cancer is exceptionally rare. Furthermore, an ectopic parathyroid adenoma in the retropharyngeal space is exceedingly rare. Therefore, anatomical variations through the utilization of relevant diagnostic tools play a crucial role in guiding decisions pertaining to clinical manifestations, diagnostic methods, surgical interventions, and operative strategies for parathyroid tumors. We present a case of a 51-year-old female patient with papillary thyroid carcinoma in the right thyroid lobe and an ectopic parathyroid adenoma in the retropharyngeal space confirmed through surgical intervention. The elevated preoperative levels of serum calcium and parathyroid hormone, along with low serum phosphate, returned to normal ranges after surgery. This case sheds light on the unusual occurrence of an ectopic parathyroid adenoma in the retropharyngeal region within a thyroid cancer patient, providing valuable insights into the realm of thyroid malignancies.

Traumatic Anterior Cervical Disc Herniation Presenting as Severe Dysphagia.

Due to the anatomical characteristics of the cervical spine, few cases of traumatic anterior cervical disc herniation have been reported in the literature. Here, we present a rare case of a traumatic anterior cervical disc herniation presenting as severe dysphagia. A 75-year-old male patient presented with severe dysphagia following an accident three days prior when he fell from a height of stairs. Cervical magnetic resonance (MR) imaging revealed a 1.3 × 1.0 cm extruded disc in the anterior aspect of the C4 level with the base at the C3-4 disc, which displaced the esophagus anteriorly. Esophagography revealed an extrinsic esophageal lesion that was considered to be responsible for the obstruction of the airway at the same level. He underwent a ruptured disc removal via the anterior approach. Preoperative dysphagia was resolved gradually after surgery, and he remained asymptomatic six months after surgery.

Inhibitory Effect of Thymol on Tympanostomy Tube Biofilms of Methicillin-Resistant Staphylococcus aureus and Ciprofloxacin-Resistant Pseudomonas aeruginosa.

The formation of antibiotic-resistant strain biofilms in tympanostomy tubes results in persistent and refractory otorrhea. In the present study, we investigated the in vitro antibiofilm activity of thymol against biofilms formed by methicillin-resistant Staphylococcus aureus (MRSA) and ciprofloxacin-resistant Pseudomonas aeruginosa (CRPA), using live and dead bacterial staining and adhesion, biofilm formation, biofilm eradication, and biofilm hydrolytic activity assays. The antibiofilm activity of thymol against tympanostomy tube biofilms formed by MRSA and CRPA strains was examined using a scanning electron microscope. In response to thymol treatment, we detected significant concentration-dependent reductions in the viability and adhesion of MRSA and CRPA. Exposure to thymol also inhibited the formation of both MRSA and CRPA biofilms. Furthermore, thymol was observed to enhance the eradication of preformed mature biofilms produced by MRSA and CRPA and also promoted a reduction in the rates of MRSA and CRPA hydrolysis. Exposure to thymol eradicated extracellular polysaccharide present in the biofilm matrix produced by MRSA and CRPA. Additionally, thymol was observed to significantly eradicate MRSA and CRPA biofilms that had formed on the surface on tympanostomy tubes. Collectively, our findings indicate that thymol is an effective inhibitor of MRSA and CRPA biofilms, and accordingly has potential utility as a therapeutic agent for the treatment of biofilm-associated refractory post-tympanostomy tube otorrhea resulting from MRSA and CRPA infection.

Novel electrochemical PMI marker biosensor based on quantum dot dissolution using a double-label strategy.

A novel and facile post-mortem interval (PMI) biosensor was fabricated using a double-label strategy to detect the glyceraldehyde 3-phosphate dehydrogenase (GAPDH) biomarker. A monoclonal anti-GAPDH antibody was immobilized on a surface label containing cadmium selenide quantum dots (CdSe QDs) on a cysteamine graphene oxide (Cys-GO) self-assembled monolayer. Glucose oxidase (GOx) was used as a signal label to conjugate with GAPDH. GAPDH recognition was achieved through the dissolution of the surface-attached CdSe QDs by hydrogen peroxide generated through GAPDH-conjugated GOx-catalyzed ß-glucose oxidation. To enhance sensitivity, a competitive interaction was introduced between free and conjugated GAPDH to the active site of the anti-GAPDH antibody. The electrochemical response due to CdSe dissolution decreased proportionally with the concentration of free GAPDH. Differential pulsed voltammetry was conducted to determine the analytical characteristics of the immunosensor, including the limit of detection, linear dynamic range, target selectivity, system stability, and applicability toward the analysis of real samples.

Paper-based multiplex analytical device for simultaneous detection of Clostridioides difficile toxins and glutamate dehydrogenase.

We report a new paper-based multiplex analytical device (mPAD) for simultaneous screening of three analytes (glutamate dehydrogenase, toxin A, and toxin B) known as biomarkers for Clostridioides difficile infection (CDI). To overcome the limitation of common rapid assays (e.g. lateral flow immunochromatographic and enzyme immunoassays) in terms of multiplexing, sensitivity, simplicity, and ease-of-use, the mPAD is constructed with a three dimensional (3D) configuration of paper components with a multi-channel design. Multiple fluidic paths developed with wax-patterned paper allow the simultaneous detection of glutamate dehydrogenase, toxin A, and toxin B without any cross-reactivity. The 3D fluidic network on the mPAD facilitates a self-operating test procedure for the mixing and addition of amplification reagents with a one-step sliding operation. The results of the multiplex CDI assay can be easily interpreted by the naked eye within 10 min, and are visually intensified over time resulting in up to 3-fold signal amplification. Our device exhibited remarkable analytical performances for the simultaneous detection of three CDI biomarkers, providing a sensitivity of 97%, specificity of 88%, accuracy of 95%, and limits of detection for glutamate dehydrogenase, toxin A, and toxin B of 0.16 ng mL-1, 0.09 ng mL-1, and 0.03 ng mL-1, respectively. These results indicate the high applicability and feasibility of mPAD for multiplex testing for CDI with the advantages of being simple, sensitive, inexpensive, user-friendly, and equipment-free.

Reduced mitophagy in the cochlea of aged C57BL/6J mice.

An increase in mitochondrial damage has been associated with a decline in the ability to mitigate damage through mitophagy in age-related pathologies. The present study aimed to investigate the changes of mitophagy in a mouse model with age-related hearing loss. C57BL/6J mice were divided into two groups: young (1 month) and aged (12 months). Hearing tests were conducted through the measurement of auditory brainstem response (ABR). Mitochondrial DNA copy number, the level of mitochondrial DNA damage, mitochondrial biogenesis, and mitophagy-related genes and proteins were investigated using real-time PCR and western blot analysis. Coexpression of mitophagosomes and lysosomes in the cochlea was investigated through immunofluorescence imaging analysis. Major players of mitophagy, Parkin and BNIP3, were also investigated through immunohistochemical staining in the cochlea. Hearing thresholds were observed to have increased in the aged group. The mitochondrial DNA copy number, PGC-1α, and PGC-1ß significantly decreased in the cochlea of mice in the aged group. The mRNA levels of PINK1, Parkin, MUL1, Atg5, Atg12, Atg13, NIX, and BNIP3 significantly decreased in the cochlea of the mice in the aged group. The level of mitochondrial DNA damage significantly increased in the cochlea of mice in the aged group. Protein levels of PINK1, Parkin, BNIP3, COX4, LC3B, and all OXPHOS subunits significantly decreased in the cochlea of the mice in the aged group. Immunofluorescence imaging analysis of mitophagosomes and lysosomes revealed a decrease in the colocalization in the cochlea of mice in the aged group. Immunohistochemical imaging analysis of Parkin and BNIP3 revealed their decreased expression in aged cochlea. Our results indicate that reduced mitophagy with aging might be attributed to the cellular changes that occur in aged cochlea in the development of age-related hearing loss.

Oleanolic acid 3-acetate, a minor element of ginsenosides, induces apoptotic cell death in ovarian carcinoma and endometrial carcinoma cells via the involvement of a reactive oxygen species-independent mitochondrial pathway.

OBJECTIVES: Oleanolic acid, a minor element of ginsenosides, and its derivatives have been shown to have cytotoxicity against some tumor cells. The impact of cytotoxic effect of oleanolic acid 3-acetate on ovarian cancer SKOV3 cells and endometrial cancer HEC-1A cells were examined both in vivo and in vitro to explore the underlying mechanisms. METHODS: Cytotoxic effects of oleanolic acid 3-acetate were assessed by cell viability, phosphatidylserine exposure on the cell surface, mitochondrial release of cytochrome C, nuclear translocation of apoptosis-inducing factor, depolarization of mitochondrial transmembrane potential (ΔΨm), and generation of reactive oxygen species (ROS). In vivo inhibition of tumor growth was also assessed with xenografts in immunocompromised mice. RESULTS: Oleanolic acid 3-acetate exhibited potent cytotoxicity toward SKOV3 and HEC-1A cells by decreasing cell viability in a concentration-dependent manner. Importantly, oleanolic acid 3-acetate effectively suppressed the growth of SKOV3 cell tumor xenografts in immunocompromised mice. Furthermore, oleanolic acid 3-acetate induced apoptotic cell death as revealed by loss of ΔΨm, release of cytochrome c, and nuclear translocation of apoptosis-inducing factor with a concomitant activation of many proapoptotic cellular components including poly(ADP-ribose) polymerase, Bcl-2, and caspases-8, caspase-3, and caspase-7. Oleanolic acid 3-acetate, however, caused a decrease in ROS production, suggesting the involvement of an ROS-independent pathway in oleanolic acid 3-acetate-induced apoptosis in SKOV3 and HEC-1A cells. CONCLUSION: These findings support the notion that oleanolic acid 3-acetate could be used as a potent anticancer supplementary agent against ovarian and endometrial cancer. Oleanolic acid 3-acetate exerts its proapoptotic effects through a rather unique molecular mechanism that involves an unconventional ROS-independent but mitochondria-mediated pathway.

Protective Effect of Tempol against Cisplatin-Induced Ototoxicity.

One of the major adverse effects of cisplatin chemotherapy is hearing loss. Cisplatin-induced ototoxicity hampers treatment because it often necessitates dose reduction, which decreases cisplatin efficacy. This study was performed to investigate the effect of Tempol on cisplatin-induced ototoxicity in an auditory cell line, House Ear Institute-Organ of Corti 1 (HEI-OC1). Cultured HEI-OC1 cells were exposed to 30 µM cisplatin for 24 h with or without a 2 h pre-treatment with Tempol. Cell viability was determined using 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay and apoptotic cells were identified using terminal deoxynucleotidyl transferase dUTP nick end labeling of nuclei (TUNEL) assay and flow cytometry. The effects of Tempol on cisplatin-induced cleaved poly(ADP-ribose) polymerase, cleaved caspase, and mitochondrial inducible nitric oxide synthase expression were evaluated using western blot analysis. Levels of intracellular reactive oxygen species (ROS) were measured to assess the effects of Tempol on cisplatin-induced ROS accumulation. Mitochondria were evaluated by confocal microscopy, and the mitochondrial membrane potential was measured to investigate whether Tempol protected against cisplatin-induced mitochondrial dysfunction. Cisplatin treatment decreased cell viability, and increased apoptotic features and markers, ROS accumulation, and mitochondrial dysfunction. Tempol pre-treatment before cisplatin exposure significantly inhibited all these cisplatin-induced effects. These results demonstrate that Tempol inhibits cisplatin-induced cytotoxicity in HEI-OC1, and could play a preventive role against cisplatin-induced ototoxicity.

Syndecan-1 overexpression promotes tumor growth and angiogenesis in an endometrial cancer xenograft model.

OBJECTIVES: Upregulation of syndecan-1, a member of the transmembranous proteoglycans that serves as a coreceptor for a wide pool of extracellular ligands, has been well documented in enabling the promotion of growth and invasion of endometrial cancer. As a step toward understanding a potential role for syndecan-1 in this process, we questioned whether syndecan-1 upregulates tumor-promoting characteristics, particularly, angiogenesis in an in vivo human xenograft tumor model. METHODS: Human syndecan-1 was stably transfected into human endometrial adenocarcinoma 1A cells, and resulting transfectants were subcutaneously grafted into athymic mice; their outcomes were examined with respect to the enhancement of tumor growth and angiogenesis by immunohistochemistry, immunoblotting, and zymography. RESULTS: Overexpression of syndecan-1 promoted tumor growth concomitant with increased angiogenesis in tumor xenografts as evidenced by an increase in immunoreactivity for vascular endothelial growth factor and vascular endothelial cell marker CD34. Furthermore, zymographic studies revealed that syndecan-1 overexpression markedly enhanced activities of matrix metalloproteinases 2 and 9. CONCLUSIONS: This is the first in vivo xenograft analysis providing evidence that supports that syndecan-1 has a critical role in carcinogenic progression, particularly, contributing to the development of angiogenesis and invasive phenotype in association with matrix metalloproteinases 2 and 9 activations in endometrial cancer.

Syndecan-1 enhances the endometrial cancer invasion by modulating matrix metalloproteinase-9 expression through nuclear factor kappaB.

OBJECTIVES: Up-regulated expression of syndecan-1, a member of the transmembranous proteoglycans that serves as a co-receptor for a wide pool of extracellular ligands, has been ascribed to the promotion of growth of various cancers including breast, ovarian, and endometrial cancers. Here, we have extended these observations to gain insight into correlation between the expression level of syndecan-1 and its tumor-promoting characteristics, particularly, cancer invasion, in endometrial cancer. METHODS: Human syndecan-1 was stably transfected into three human endometrial cancer cell lines, and its effects were examined with respect to cell survival/proliferation and invasion. In addition, the activation of underlying signaling components, including integrins, focal adhesion kinase (FAK), and nuclear factor kappaB (NF-kappaB) was examined. The activity of NF-kappaB as a transcription factor for matrix metalloproteinase (MMP)-9 was assessed. RESULTS: The innate expression level of syndecan-1 was moderate to high in all endometrial cancer cell lines. Overexpression of syndecan-1 promoted tumor cell proliferation concomitant with the activation of NF-kappaB. Furthermore, overexpression of syndecan-1 markedly enhanced the cancer invasion accompanied by enhanced expression of integrin alphav/beta5 and enhanced phosphorylation of FAK. The transcriptional activation of MMP-9 by NF-kappaB was up-regulated in syndecan-1 overexpression. CONCLUSION: These findings provide evidence that supports that syndecan-1 may have a critical role in carcinogenic progression, particularly, contributing to the development of proliferative and invasive phenotype through NF-kappaB-mediated MMP-9 gene expression in endometrial cancer.