Engineering Anti-CRISPR Proteins to Create CRISPR-Cas Protein Switches for Activatable Genome Editing and Viral Protease Detection.

Proteins capable of switching between distinct active states in response to biochemical cues are ideal for sensing and controlling biological processes. Activatable CRISPR-Cas systems are significant in precise genetic manipulation and sensitive molecular diagnostics, yet directly controlling Cas protein function remains challenging. Herein, we explore anti-CRISPR (Acr) proteins as modules to create synthetic Cas protein switches (CasPSs) based on computational chemistry-directed rational protein interface engineering. Guided by molecular fingerprint analysis, electrostatic potential mapping, and binding free energy calculations, we rationally engineer the molecular interaction interface between Cas12a and its cognate Acr proteins (AcrVA4 and AcrVA5) to generate a series of orthogonal protease-responsive CasPSs. These CasPSs enable the conversion of specific proteolytic events into activation of Cas12a function with high switching ratios (up to 34.3-fold). These advancements enable specific proteolysis-inducible genome editing in mammalian cells and sensitive detection of viral protease activities during virus infection. This work provides a promising strategy for developing CRISPR-Cas tools for controllable gene manipulation and regulation and clinical diagnostics.

Orbitofrontal cholesterol granuloma masquerading as frontal sinus mucoceles: report of two cases.

BACKGROUND: Two cases of orbitofrontal cholesterol granuloma masquerading as frontal sinus mucoceles were reported to understand image findings, clinical and histopathologic features of orbitofrontal cholesterol granuloma to improve its diagnosis and treatment. CASE PRESENTATION: Two East Asian patients aged 41 and 27 without personal or familial medical or trauma history presented with the common complaint of proptosis and inferomedial displacement of the eyeballs. The computed tomography (CT) of both cases showed an irregularly shaped, well-defined lesion in the left frontal bone associated with bony erosion. The lesions resulted in the bone absorption of frontal bone and orbital roof, which extended into the superior orbital space. Anterior orbitotomy through subbrow incision by drainage and curettage resulted in a curative outcome. The histopathological examination revealed inflammatory granulation tissues, fibrous capsule wall, cholesterol clefts with altered blood pigments, and calcifications, consistent with the diagnosis of cholesterol granuloma. No recurrence was observed for one year after surgery in one case and three years in the other. CONCLUSIONS: When the following features are observed: orbital CT exhibits cystic lesion with irregular bone destruction in the superolateral orbit, magnetic resonance imaging (MRI) depicts lesions are hyperintense signals on T1 weighted images (T1WI), and T2 weighted images (T2WI), and the contrast-enhanced imaging reveals that the most of tumor is showed a non-significant enhancement, orbitofrontal cholesterol granuloma should be considered.

Clinical characteristics and prognosis of orbital solitary fibrous tumor in patients from a Chinese tertiary eye hospital.

BACKGROUND: Solitary fibrous tumor (SFT) is predominant within the pleura but very rare in the orbit, which is why the diagnosis of orbital SFT poses challenges in clinical practice. Accordingly, an integrated approach that incorporates specific clinical features, histological, histopathological, and immunohistochemical (IHC) examinations, and molecular analyses is warranted. AIM: To retrospectively explore the clinical and imaging characteristics, treatment, outcomes of a series of patients with orbital SFT. METHODS: We conducted a retrospective review of a series of patients diagnosed with a histopathologic orbital SFT treated at a single institution. All data on demogra/phics, clinical characteristics, imaging, treatment, postoperative histopathological and IHC examinations, and prognosis were collected. RESULTS: In total, 13 patients were enrolled, 7 (53.8%) of whom had the tumor located in the superomedial quadrant of the orbit. Computed tomography revealed a solitary ovoid lesion in 10 (76.9%) patients and irregular lesion in 3 (23.1%) patients. Magnetic resonance imaging results were as follows: On T1 weighted images, 3 (23.1%) patients had hypointense mixed signals, whereas 10 (76.9%) patients showed isointense mixed signals; on T2 weighted images (T2WI), 3 (23.1%), 4 (30.8%), and 6 (46.2%) patients exhibited hypointense mixed, isointense mixed, and hyperintense signals, respectively. Notably, 12 (92.3%) patients showed significant enhancement, whereas there were patchy slightly enhanced areas in the tumor. All patients were treated by surgery. IHC analysis demonstrated that the tumor cells were immunoreactive for CD34, CD99, STAT-6, and vimentin in all patients. The lesions showed Ki-67 positivity < 5% in 1 (7.7) patient, 5%-10% in 10 (76.9%), and > 10% in 2 (15.4%). Two (15.4%) patients exhibited tumor recurrence. CONCLUSION: The clinical manifestations and radiologic characteristics of orbital SFT are diverse and not specific. Accurate diagnosis and treatment require detailed radiological and histopathological/IHC evaluation.

Primary orbital monophasic synovial sarcoma with calcification: A case report.

BACKGROUND: Synovial sarcoma is a malignant mesenchymal neoplasm with variable epithelial differentiation. Most synovial sarcoma cases are reported in young adults and can arise in any body site. Notably, primary orbital synovial sarcoma is rare. CASE SUMMARY: An 8-year-old east Asian girl with 1-month history of gradual painless proptosis and lacrimation of the right eye was admitted. The patient presented with painless proptosis, downward eyeball displacement, and upward movement disorders. According to clinical manifestations, imaging examinations and postoperative immunohistochemical examinations, the diagnosis was monophasic synovial sarcoma with calcification. The patient underwent anterior orbitotomy procedure for removal of the right orbital mass under general anesthesia. The diagnosis of monophasic synovial sarcoma with calcification was confirmed finally through histological and immunohistochemical exam. The follow-up period was 6 mo, and no recurrence was observed during this period. CONCLUSION: Primary orbital monophasic synovial sarcoma with calcification is a rare sarcoma, and clinical manifestations and imaging results are not specific. The tumor may present similar features as a benign tumor. Comprehensive analysis of clinical, radiological, and pathological findings is critically important for making the right diagnosis. Conventional treatment approach for synovial sarcoma is surgical resection with adjuvant or neoadjuvant radiotherapy, which is highly effective for localized tumors.

Orbital schwannoma with calcification treated by intracapsular excision: A case report.

RATIONALE: Orbital schwannoma is a relatively rare orbital tumor, and calcification of the lesion is rarely found in the orbit. We report a case of orbital schwannoma which was characterized by calcification in the orbital muscle cone, and was cured by intracapsular excision. PATIENT CONCERNS: A 54-year-old female with a complaint of a mass in the left orbit during a magnetic resonance imaging examination and symptom of dizziness 6 months before, presented with painless exophthalmos and vision decline in the left eye. DIAGNOSES: According to clinical manifestations, imaging examinations and postoperative immunohistochemical examinations, the diagnosis was orbital schwannoma, with calcification in the muscle cone. INTERVENTIONS: The patient was treated by intracapsular excision of the left orbit. We removed the intracapsular mass and most part of the cyst wall in order to prevent orbital apex syndrome. OUTCOMES: The diagnosis of schwannoma with calcification was confirmed finally through histological and immunohistochemical exam. The patient was followed up for 28 months and the orbital CT scan showed that there were no significant lesions found in the orbital muscle cone. LESSONS: Understanding clinical, imaging diagnostic, and histopathological features of rare orbital schwannoma with calcification will facilitate timely diagnosis and treatment of this condition. The intracapsular excision can help in avoiding complications.