A Descriptive Observational Study of GJB2 and GJB6 Mutations in Familial Autosomal Recessive Non-syndromic Hearing Impairment.

Mutations in the genes, GJB2 and GJB6 play an important role in autosomal recessive, non-syndromic hearing loss. This study is aimed to detect the association of mutations in GJB2 and GJB6 genes in familial autosomal recessive non-syndromic hearing impairment cases. We included 26 families with at least two affected individuals having congenital bilateral, non-syndromic sensorineural hearing loss. Blood samples were drawn, DNA was extracted, and sent for multiplex PCR and Sanger sequencing. Of the 26 families analyzed, GJB2 mutations were detected in 9(34.6%) and GJB6 mutations were not detected in any of the families. GJB2 mutations are a major cause of congenital, non-syndromic hearing loss in this study population. This study also suggests that GJB6 mutations do not contribute to autosomal recessive non-syndromic hearing loss in the Indian population.

Development, Establishment, and Validation of a Model for the Mineralization of Periodontium Remodelling Cells: Cementoblasts.

Chronic kidney disease (CKD) patients undergoing dialysis are at high risk of bone fractures. CKD-induced mineral and bone disorder is extended to periodontal disease due to changes in the ionic composition of saliva in CKD patients, dysregulating mineralization, hindering regeneration and thereby promoting the progression of dental complications. Despite the importance of cementum for overall oral health, the mechanisms that regulate its development and regeneration are not well comprehended, and a lack of sufficient in vitro experimental models has hindered research progress. In this study, the impact of experimental conditions on the calcification of cementoblasts was systematically investigated, aimed at establishing a standardized and validated model for the calcification of cementoblasts. The effects of phosphate, calcium, ascorbic acid, ß-glycerolphosphate, dexamethasone, and fetal calf serum on the calcification process of cementoblasts were analyzed over a wide range of concentrations and time points by investigating calcium content, cell viability, gene expression and kinase activity. Cementoblasts calcified in a concentration- and time-dependent manner with higher concentrations of supplements cause a higher degree of calcification but decreased cell viability. Phosphate and calcium have a significantly stronger effect on cementoblast calcification processes compared to osteogenic supplements: ascorbic acid, ß-glycerolphosphate, and dexamethasone induce calcification over a wide range of osteogenic signalling pathways, with osteopontin being a central target of gene regulation. Conversely, treatment with ascorbic acid, ß-glycerolphosphate, and dexamethasone leads to activating only selected pathways, especially promoting bone sialoprotein expression. The developed and validated cementoblast calcification protocol, incubating up to 60% confluent cementoblasts with 1.9 mmol L-1 of phosphate supplementation for a reasonable, multi-pathway calcification induction and 10 mmol L-1 ß-glycerolphosphate, 75 µmol L-1 ascorbic acid and 10 nmol L-1 dexamethasone for a reasonable osteogenic differentiation-based calcification induction, provides standard in vitro experimental models for better understanding cementoblast function and regeneration.

Primary Hyperparathyroidism in a 21 Year Old Patient of Turner Syndrome : A Rare Case Report.

Turner syndrome is the most common chromosomal anomaly in females. The typical features include short stature, amenorrhoea, short webbed neck, shielded chest and many comorbidities like osteoporosis, cardiac anomalies, diabetes and hypothyroidism. Primary hyperparathyroidism caused by parathyroid adenoma is rarely reported in patients of turner syndrome. The exact cause is not known at present. We report a case of a 21 years old patient of Turner syndrome who had symptoms of renal stones and hypercalcemia. USG neck and sestamibi scans revealed left inferior parathyroid adenoma. Surgical excision of the involved gland was done which led to normalization of S. calcium and PTH levels. Although hyperparathyroidism is extremely rare in patients of Turner syndrome, any symptoms of renal stones, pathological fractures and hypercalcemia should raise the suspicion of parathyroid adenoma. Surgical management should be planned as early as possible.

Fosl1: friend or foe?

Fos-like antigen 1 (Fosl1) is a protein that belongs to the Fos family of transcription factors. Fosl1 has an impact on (i) carcinogenesis, (ii) acute kidney injury, and (iii) fibroblast growth factor expression. Recently, the nephroprotective effect of Fosl1 by the preservation of Klotho expression was recently identified. The identification of a link between Fosl1 and Klotho expression provides an entirely new field of nephroprotection.

COVID Associated Invasive Aspergillosis.

To study the possible association between invasive fungal sinusitis (aspergillosis) and coronavirus disease. An observational study was conducted at a tertiary care centre over 6 months, involving all patients with aspergillosis of the paranasal sinuses suffering from or having a history of COVID-19 infection. 92 patients presented with aspergillosis, all had an association with COVID-19 disease. Maxillary sinus (100%) was the most common sinus affected. Intraorbital extension was seen in 34 cases, while intracranial extension was seen in 5 cases. Diabetes mellitus was present in 75 of 92 cases. All had a history of steroid use during their coronavirus treatment. New manifestations of COVID-19 are appearing over time. The association between coronavirus and aspergillosis of the paranasal sinuses must be given serious consideration. Uncontrolled diabetes and overzealous use of steroids are two main factors aggravating the illness, and both of these must be properly checked.

Post Covid-19 Sinonasal Candidiasis: A Crisis Within the Pandemic.

The aim of this study was to find out the association of sinonasal candidiasis and Covid-19 infection. A prospective observational study was conducted at a tertiary care centre from April to September 2021, involving all patients with invasive candidiasis of the paranasal sinuses having a history of Covid-19 infection. A total of 18 patients of covid associated sinonasal candidiasis among the 475 cases of fungal rhinosinusitis were studied. All patients had involvement of nose and sinuses and 2 patients had orbital involvement with no loss of vision, while 3 had intracranial extensions and 1 had pulmonary involvement. Mandible was involved in 1 patient alone, while the maxilla and palate were involved in 5 patients. 15 patients were hypertensive, 12 diabetics and 1 had aplastic anaemia. Cultures showed that 8 patients had C. parapsilosis, 5 had C. albicans, 3 had C. tropicalis and 2 had mixed fungal infections. All patients underwent surgical debridement and antifungal administration. They were followed up for a minimum of 3 months. There was only one mortality (with aplastic anaemia), rest 17 were disease free at the time of writing this article. This is perhaps the first case series of post covid sinonasal candidiasis in the world. Invasive sinonasal candidiasis is a newer sequela of COVID-19 infection. Uncontrolled diabetes and over-zealous use of steroids at the time of Covid-19 are few of the known risk factors. Early surgical intervention and anti-fungal treatment should be sought for management.

Anterior and Central Skull Base Fibrous Dysplasia: A 12 Years' Experience.

Fibrous dysplasia, specially of anterior and central skull base region, is a rare disorder. This article discusses about our experience in this pathology. A tertiary care institute based retrospective type study was conducted over a period of 12 years. Demographics, radiology, intraoperative details, pathology and follow up were taken into consideration and the data was analysed. Sixteen patients with complaints of proptosis, diplopia, nasal obstruction and/or facial deformity, underwent endoscopic sinus surgery. Subtotal resection was done in 5 patients. Ethmoid bone involvement was seen in 12 patients. Post operatively, diplopia persisted in one patient and one patient had epistaxis. All patients were followed up for 2-10 years with no other complications reported. Anterior and central skull base involvement is rare in fibrous dysplasia. However, it can be removed effectively by endoscopic approach. Overall safety of patient has more concern rather than complete removal of disease.

Xanthohumol exerts anti-inflammatory effects in an in vitro model of mechanically stimulated cementoblasts.

Xanthohumol (XN) is a prenylated plant polyphenol that naturally occurs in hops and its products, e.g. beer. It has shown to have anti-inflammatory and angiogenesis inhibiting effects and it prevents the proliferation of cancer cells. These effects could be in particular interesting for processes within the periodontal ligament, as previous studies have shown that orthodontic tooth movement is associated with a sterile inflammatory reaction. Based on this, the study evaluates the anti-inflammatory effect of XN in cementoblasts in an in vitro model of the early phase of orthodontic tooth movement by compressive stimulation. XN shows a concentration-dependent influence on cell viability. Low concentrations between 0.2 and 0.8 µM increase viability, while high concentrations between 4 and 8 µM cause a significant decrease in viability. Compressive force induces an upregulation of pro-inflammatory gene (Il-6, Cox2, Vegfa) and protein (IL-6) expression. XN significantly reduces compression related IL-6 protein and gene expression. Furthermore, the expression of phosphorylated ERK and AKT under compression was upregulated while XN re-established the expression to a level similar to control. Accordingly, we demonstrated a selective anti-inflammatory effect of XN in cementoblasts. Our findings provide the base for further examination of XN in modulation of inflammation during orthodontic therapy and treatment of periodontitis.

Lipids and lipoproteins in cardiovascular diseases: a classification.

Lipids and lipoproteins, their metabolism, and their transport are essential contributing factors of cardiovascular disease (CVD) as they regulate plasma cholesterol concentration, enhancing cholesterol uptake by macrophages, leading to foam cell formation and ultimately resulting in plaque formation and inflammation. However, lipids and lipoproteins have cardioprotective functions as well, such as preventing oxidation of proatherogenic molecules and downregulating inflammatory proteins.

Transcription Elongation Machinery Is a Druggable Dependency and Potentiates Immunotherapy in Glioblastoma Stem Cells.

Glioblastoma (GBM) is the most lethal primary brain cancer characterized by therapeutic resistance, which is promoted by GBM stem cells (GSC). Here, we interrogated gene expression and whole-genome CRISPR/Cas9 screening in a large panel of patient-derived GSCs, differentiated GBM cells (DGC), and neural stem cells (NSC) to identify master regulators of GSC stemness, revealing an essential transcription state with increased RNA polymerase II-mediated transcription. The YY1 and transcriptional CDK9 complex was essential for GSC survival and maintenance in vitro and in vivo. YY1 interacted with CDK9 to regulate transcription elongation in GSCs. Genetic or pharmacologic targeting of the YY1-CDK9 complex elicited RNA m6A modification-dependent interferon responses, reduced regulatory T-cell infiltration, and augmented efficacy of immune checkpoint therapy in GBM. Collectively, these results suggest that YY1-CDK9 transcription elongation complex defines a targetable cell state with active transcription, suppressed interferon responses, and immunotherapy resistance in GBM. SIGNIFICANCE: Effective strategies to rewire immunosuppressive microenvironment and enhance immunotherapy response are still lacking in GBM. YY1-driven transcriptional elongation machinery represents a druggable target to activate interferon response and enhance anti-PD-1 response through regulating the m6A modification program, linking epigenetic regulation to immunomodulatory function in GBM.This article is highlighted in the In This Issue feature, p. 275.

COVID-19, Diabetes and Steroids: The Demonic Trident for Mucormycosis.

Coronavirus disease 2019 (COVID-19) has been found to be associated with mucormycosis in few parts of the world, especially India. It is important to look for reasons for this upsurge of cases so that other countries may take proper steps to prevent it. A prospective clinico-demographic study was conducted in SMS Medical College, Jaipur, India from April to May 2021. All patients (235) with COVID associated mucormycosis (CAM) were studied in detail with reference to their diabetic status and steroid intake during treatment of COVID-19. Steroid usage was in 84.3% of patients with methylprednisolone being the most commonly used steroid (66.8%). Majority of the patients had taken steroids for 7-14 days. Diabetes was found in 204 patients and 42.1% of patients were newly diagnosed during/after COVID-19 treatment. The HbA1c levels of diabetic patients ranged from 6.0% to 16.3%. This is perhaps the biggest study in the world shows that the triad of COVID-19, diabetes and steroid usage is a major contributing factor towards mucormycosis. Proper steps should be taken to prevent CAM.

Establishment of Patient-Derived Succinate Dehydrogenase-Deficient Gastrointestinal Stromal Tumor Models for Predicting Therapeutic Response.

PURPOSE: Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the gastrointestinal tract, with mutant succinate dehydrogenase (SDH) subunits (A-D) comprising less than 7.5% (i.e., 150-200/year) of new cases annually in the United States. Contrary to GISTs harboring KIT or PDGFRA mutations, SDH-mutant GISTs affect adolescents/young adults, often metastasize, and are frequently resistant to tyrosine kinase inhibitors (TKI). Lack of human models for any SDH-mutant tumors, including GIST, has limited molecular characterization and drug discovery. EXPERIMENTAL DESIGN: We describe methods for establishing novel patient-derived SDH-mutant (mSDH) GIST models and interrogated the efficacy of temozolomide on these tumor models in vitro and in clinical trials of patients with mSDH GIST. RESULTS: Molecular and metabolic characterization of our patient-derived mSDH GIST models revealed that these models recapitulate the transcriptional and metabolic hallmarks of parent tumors and SDH deficiency. We further demonstrate that temozolomide elicits DNA damage and apoptosis in our mSDH GIST models. Translating our in vitro discovery to the clinic, a cohort of patients with SDH-mutant GIST treated with temozolomide (n = 5) demonstrated a 40% objective response rate and 100% disease control rate, suggesting that temozolomide represents a promising therapy for this subset of GIST. CONCLUSIONS: We report the first methods to establish patient-derived mSDH tumor models, which can be readily employed for understanding patient-specific tumor biology and treatment strategies. We also demonstrate that temozolomide is effective in patients with mSDH GIST who are refractory to existing chemotherapeutic drugs (namely, TKIs) in clinic for GISTs, bringing a promising treatment option for these patients to clinic.See related commentary by Blakely et al., p. 3.

The RNA m6A Reader YTHDF2 Maintains Oncogene Expression and Is a Targetable Dependency in Glioblastoma Stem Cells.

Glioblastoma is a universally lethal cancer driven by glioblastoma stem cells (GSC). Here, we interrogated N 6-methyladenosine (m6A) mRNA modifications in GSCs by methyl RNA immunoprecipitation followed by sequencing and transcriptome analysis, finding transcripts marked by m6A often upregulated compared with normal neural stem cells (NSC). Interrogating m6A regulators, GSCs displayed preferential expression, as well as in vitro and in vivo dependency, of the m6A reader YTHDF2, in contrast to NSCs. Although YTHDF2 has been reported to destabilize mRNAs, YTHDF2 stabilized MYC and VEGFA transcripts in GSCs in an m6A-dependent manner. We identified IGFBP3 as a downstream effector of the YTHDF2-MYC axis in GSCs. The IGF1/IGF1R inhibitor linsitinib preferentially targeted YTHDF2-expressing cells, inhibiting GSC viability without affecting NSCs and impairing in vivo glioblastoma growth. Thus, YTHDF2 links RNA epitranscriptomic modifications and GSC growth, laying the foundation for the YTHDF2-MYC-IGFBP3 axis as a specific and novel therapeutic target in glioblastoma. SIGNIFICANCE: Epitranscriptomics promotes cellular heterogeneity in cancer. RNA m6A landscapes of cancer and NSCs identified cell type-specific dependencies and therapeutic vulnerabilities. The m6A reader YTHDF2 stabilized MYC mRNA specifically in cancer stem cells. Given the challenge of targeting MYC, YTHDF2 presents a therapeutic target to perturb MYC signaling in glioblastoma.This article is highlighted in the In This Issue feature, p. 211.

The Meningioma Enhancer Landscape Delineates Novel Subgroups and Drives Druggable Dependencies.

Meningiomas are the most common primary intracranial tumor with current classification offering limited therapeutic guidance. Here, we interrogated meningioma enhancer landscapes from 33 tumors to stratify patients based upon prognosis and identify novel meningioma-specific dependencies. Enhancers robustly stratified meningiomas into three biologically distinct groups (adipogenesis/cholesterol, mesodermal, and neural crest) distinguished by distinct hormonal lineage transcriptional regulators. Meningioma landscapes clustered with intrinsic brain tumors and hormonally responsive systemic cancers with meningioma subgroups, reflecting progesterone or androgen hormonal signaling. Enhancer classification identified a subset of tumors with poor prognosis, irrespective of histologic grading. Superenhancer signatures predicted drug dependencies with superior in vitro efficacy to treatment based upon the NF2 genomic profile. Inhibition of DUSP1, a novel and druggable meningioma target, impaired tumor growth in vivo. Collectively, epigenetic landscapes empower meningioma classification and identification of novel therapies. SIGNIFICANCE: Enhancer landscapes inform prognostic classification of aggressive meningiomas, identifying tumors at high risk of recurrence, and reveal previously unknown therapeutic targets. Druggable dependencies discovered through epigenetic profiling potentially guide treatment of intractable meningiomas.This article is highlighted in the In This Issue feature, p. 1611.

Three-dimensional bioprinted glioblastoma microenvironments model cellular dependencies and immune interactions.

Brain tumors are dynamic complex ecosystems with multiple cell types. To model the brain tumor microenvironment in a reproducible and scalable system, we developed a rapid three-dimensional (3D) bioprinting method to construct clinically relevant biomimetic tissue models. In recurrent glioblastoma, macrophages/microglia prominently contribute to the tumor mass. To parse the function of macrophages in 3D, we compared the growth of glioblastoma stem cells (GSCs) alone or with astrocytes and neural precursor cells in a hyaluronic acid-rich hydrogel, with or without macrophage. Bioprinted constructs integrating macrophage recapitulate patient-derived transcriptional profiles predictive of patient survival, maintenance of stemness, invasion, and drug resistance. Whole-genome CRISPR screening with bioprinted complex systems identified unique molecular dependencies in GSCs, relative to sphere culture. Multicellular bioprinted models serve as a scalable and physiologic platform to interrogate drug sensitivity, cellular crosstalk, invasion, context-specific functional dependencies, as well as immunologic interactions in a species-matched neural environment.

Glioblastoma Stem Cells: Driving Resilience through Chaos.

Glioblastoma is an aggressive and heterogeneous tumor in which glioblastoma stem cells (GSCs) are at the apex of an entropic hierarchy and impart devastating therapy resistance. The high entropy of GSCs is driven by a permissive epigenetic landscape and a mutational landscape that revokes crucial cellular checkpoints. The GSC population encompasses a complex array of diverse microstates that are defined and maintained by a wide variety of attractors including the complex tumor ecosystem and therapeutic intervention. Constant dynamic transcriptional fluctuations result in a highly adaptable and heterogeneous entity primed for therapy evasion and survival. Analyzing the transcriptional, epigenetic, and metabolic landscapes of GSC dynamics in the context of a stochastically fluctuating tumor network will provide novel strategies to target resistant populations of GSCs in glioblastoma.

Targeting pyrimidine synthesis accentuates molecular therapy response in glioblastoma stem cells.

Glioblastoma stem cells (GSCs) reprogram glucose metabolism by hijacking high-affinity glucose uptake to survive in a nutritionally dynamic microenvironment. Here, we trace metabolic aberrations in GSCs to link core genetic mutations in glioblastoma to dependency on de novo pyrimidine synthesis. Targeting the pyrimidine synthetic rate-limiting step enzyme carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, dihydroorotase (CAD) or the critical downstream enzyme dihydroorotate dehydrogenase (DHODH) inhibited GSC survival, self-renewal, and in vivo tumor initiation through the depletion of the pyrimidine nucleotide supply in rodent models. Mutations in EGFR or PTEN generated distinct CAD phosphorylation patterns to activate carbon influx through pyrimidine synthesis. Simultaneous abrogation of tumor-specific driver mutations and DHODH activity with clinically approved inhibitors demonstrated sustained inhibition of metabolic activity of pyrimidine synthesis and GSC tumorigenic capacity in vitro. Higher expression of pyrimidine synthesis genes portends poor prognosis of patients with glioblastoma. Collectively, our results demonstrate a therapeutic approach of precision medicine through targeting the nexus between driver mutations and metabolic reprogramming in cancer stem cells.

Glioblastoma stem cells: lessons from the tumor hierarchy in a lethal cancer.

Glioblastoma ranks among the most lethal of all human cancers. Glioblastomas display striking cellular heterogeneity, with stem-like glioblastoma stem cells (GSCs) at the apex. Although the original identification of GSCs dates back more than a decade, the purification and characterization of GSCs remains challenging. Despite these challenges, the evidence that GSCs play important roles in tumor growth and response to therapy has grown. Like normal stem cells, GSCs are functionally defined and distinguished from their differentiated tumor progeny at core transcriptional, epigenetic, and metabolic regulatory levels, suggesting that no single therapeutic modality will be universally effective against a heterogenous GSC population. Glioblastomas induce a systemic immunosuppression with mixed responses to oncoimmunologic modalities, suggesting the potential for augmentation of response with a deeper consideration of GSCs. Unfortunately, the GSC literature has been complicated by frequent use of inferior cell lines and a lack of proper functional analyses. Collectively, glioblastoma offers a reliable cancer to study cancer stem cells to better model the human disease and inform improved biologic understanding and design of novel therapeutics.

Glioma Stem Cell-Specific Superenhancer Promotes Polyunsaturated Fatty-Acid Synthesis to Support EGFR Signaling.

Glioblastoma ranks among the most aggressive and lethal of all human cancers. Functionally defined glioma stem cells (GSC) contribute to this poor prognosis by driving therapeutic resistance and maintaining cellular heterogeneity. To understand the molecular processes essential for GSC maintenance and tumorigenicity, we interrogated the superenhancer landscapes of primary glioblastoma specimens and in vitro GSCs. GSCs epigenetically upregulated ELOVL2, a key polyunsaturated fatty-acid synthesis enzyme. Targeting ELOVL2 inhibited glioblastoma cell growth and tumor initiation. ELOVL2 depletion altered cellular membrane phospholipid composition, disrupted membrane structural properties, and diminished EGFR signaling through control of fatty-acid elongation. In support of the translational potential of these findings, dual targeting of polyunsaturated fatty-acid synthesis and EGFR signaling had a combinatorial cytotoxic effect on GSCs. SIGNIFICANCE: Glioblastoma remains a devastating disease despite extensive characterization. We profiled epigenomic landscapes of glioblastoma to pinpoint cell state-specific dependencies and therapeutic vulnerabilities. GSCs utilize polyunsaturated fatty-acid synthesis to support membrane architecture, inhibition of which impairs EGFR signaling and GSC proliferation. Combinatorial targeting of these networks represents a promising therapeutic strategy.See related commentary by Affronti and Wellen, p. 1161.This article is highlighted in the In This Issue feature, p. 1143.

SUFU: The Jekyll and Hyde of the Cerebellum.

Pediatric tumors have enriched the understanding of germline genotype contribution to tumorigenesis. In this issue of Developmental Cell, Yin et al. (2018) describe genetic models of Sonic Hedgehog (SHH) subgroup of medulloblastoma with SUFU alterations, painting more nuanced roles for SUFU in tumorigenesis and maintenance of Gli2 transcription factor circuitries.