Absence of vitamin D receptor (VDR)-mediated PPARγ suppression causes alopecia in VDR-null mice.

Vitamin D receptor (VDR) mutations in humans and mice cause alopecia. VDR-null (VDR-/-) mice exhibit lack of postmorphogenic hair cycles as a result of impaired keratinocyte stem cell (KSC) function. To identify the molecular basis for abnormal KSC function, RNA sequencing of wild-type (WT) and VDR-/- KSCs was performed. These studies demonstrated that >80% of differentially expressed genes are up-regulated in VDR-/- KSCs; thus, the VDR is a transcriptional suppressor in WT KSCs. Peroxisome proliferator-activated receptor γ (PPARγ), PPARγ coactivator 1ß (PGC1ß), and lipoprotein lipase (LPL) were among the up-regulated genes identified. Chromatin immunoprecipitation analyses demonstrated that these genes are direct VDR targets in WT keratinocytes. Notably, VDR occupancy of the PPARγ regulatory region precludes PPARγ occupancy of this site, based on the observation that PPARγ interacts with these sequences in VDR-/- but not WT keratinocytes. This contrasts with the VDR and PPARγ co-occupancy observed on PGC1ß and LPL gene regulatory regions identified. Studies in mice with keratinocyte-specific PPARγ haploinsufficiency were performed to identify the functional consequences of enhanced PPARγ expression. PPARγ haploinsufficiency normalized PPARγ mRNA levels in VDR-/- keratinocytes and restored anagen responsiveness in vivo in VDR-/- mice, resulting in hair regrowth. Thus, absence of VDR-mediated PPARγ suppression underlies alopecia in VDR-/- mice.-Saini, V., Zhao, H., Petit, E. T., Gori, F., Demay, M. B. Absence of vitamin D receptor (VDR)-mediated PPARγ suppression causes alopecia in VDR-null mice.

Myelopoiesis is regulated by osteocytes through Gsα-dependent signaling.

Hematopoietic progenitors are regulated in their respective niches by cells of the bone marrow microenvironment. The bone marrow microenvironment is composed of a variety of cell types, and the relative contribution of each of these cells for hematopoietic lineage maintenance has remained largely unclear. Osteocytes, the most abundant yet least understood cells in bone, are thought to initiate adaptive bone remodeling responses via osteoblasts and osteoclasts. Here we report that these cells regulate hematopoiesis, constraining myelopoiesis through a Gsα-mediated mechanism that affects G-CSF production. Mice lacking Gsα in osteocytes showed a dramatic increase in myeloid cells in bone marrow, spleen, and peripheral blood. This hematopoietic phenomenon was neither intrinsic to the hematopoietic cells nor dependent on osteoblasts but was a consequence of an altered bone marrow microenvironment imposed by Gsα deficiency in osteocytes. Conditioned media from osteocyte-enriched bone explants significantly increased myeloid colony formation in vitro, which was blocked by G-CSF­neutralizing antibody, indicating a critical role of osteocyte-derived G-CSF in the myeloid expansion.

Parathyroid hormone (PTH)/PTH-related peptide type 1 receptor (PPR) signaling in osteocytes regulates anabolic and catabolic skeletal responses to PTH.

Parathyroid hormone (PTH) is the only Food and Drug Administration-approved anabolic agent to treat osteoporosis; however, the cellular targets of PTH action in bone remain controversial. PTH modulates bone turnover by binding to the PTH/PTH-related peptide (PTHrP) type 1 receptor (PPR), a G-protein-coupled receptor highly expressed in bone and kidneys. Osteocytes, the most abundant cells in adult bone, also express PPR. However, the physiological relevance of PPR signaling in osteocytes remains to be elucidated. Toward this goal, we generated mice with PPR deletion in osteocytes (Ocy-PPRKO). Skeletal analysis of these mice revealed a significant increase in bone mineral density and trabecular and cortical bone parameters. Osteoblast activities were reduced in these animals, as demonstrated by decreased collagen type I α1 mRNA and receptor activator of NF-κB ligand (RANKL) expression. Importantly, when subjected to an anabolic or catabolic PTH regimen, Ocy-PPRKO animals demonstrated blunted skeletal responses. PTH failed to suppress SOST/Sclerostin or induce RANKL expression in Ocy-PPRKO animals compared with controls. In vitro, osteoclastogenesis was significantly impaired in Ocy-PPRKO upon PTH administration, indicating that osteocytes control osteoclast formation through a PPR-mediated mechanism. Taken together, these data indicate that PPR signaling in osteocytes is required for bone remodeling, and receptor signaling in osteocytes is needed for anabolic and catabolic skeletal responses.

Baseline findings of a multicentric ambispective cohort study (2021-2022) among hospitalised mucormycosis patients in India.

In India, the incidence of mucormycosis reached high levels during 2021-2022, coinciding with the COVID-19 pandemic. In response to this, we established a multicentric ambispective cohort of patients hospitalised with mucormycosis across India. In this paper, we report their baseline profile, clinical characteristics and outcomes at discharge. Patients hospitalized for mucormycosis during March-July 2021 were included. Mucormycosis was diagnosed based on mycological confirmation on direct microscopy (KOH/Calcofluor white stain), culture, histopathology, or supportive evidence from endoscopy or imaging. After consent, trained data collectors used medical records and telephonic interviews to capture data in a pre-tested structured questionnaire. At baseline, we recruited 686 patients from 26 study hospitals, of whom 72.3% were males, 78% had a prior history of diabetes, 53.2% had a history of corticosteroid treatment, and 80% were associated with COVID-19. Pain, numbness or swelling of the face were the commonest symptoms (73.3%). Liposomal Amphotericin B was the commonest drug formulation used (67.1%), and endoscopic sinus surgery was the most common surgical procedure (73.6%). At discharge, the disease was stable in 43.3%, in regression for 29.9% but 9.6% died during hospitalization. Among survivors, commonly reported disabilities included facial disfigurement (18.4%) and difficulties in chewing/swallowing (17.8%). Though the risk of mortality was only 1 in 10, the disability due to the disease was very high. This cohort study could enhance our understanding of the disease's clinical progression and help frame standard treatment guidelines.

Primary leiomyosarcoma of the thyroid gland.

Sarcoma is a rare tumor of the thyroid gland, primary thyroid leiomyosarcoma (LMS) being even rarer. We present a case of LMS of the thyroid in a middle-aged female. Histopathologic examination in conjunction with immunohistochemistry helped to clinch the diagnosis. Knowledge of this entity is important to distinguish it from anaplastic thyroid carcinoma (ATC) and other sarcomas arising in the thyroid and adjacent soft tissue. The prognosis of thyroid LMS is dismal with an extremely poor survival rate.

Adipose-specific VDR Deletion Leads to Hepatic Steatosis in Female Mice Fed a Low-Fat Diet.

Risk factors for nonalcoholic hepatic steatosis include obesity and vitamin D deficiency which commonly coexist. Thus, the role of vitamin D signaling in the prevention of hepatic steatosis in the absence of obesity or a "Western" high-fat diet is unclear. These studies were performed to address the role of the adipocyte vitamin D receptor (VDR) in the prevention of hepatic steatosis in mice fed a chow diet containing 5% fat by weight. Female mice with adipocyte VDR ablation (Adipoq-Cre; VDRflox/flox) exhibited a mild increase in weight gain at age 70 days, accompanied by an increase in visceral white adipose tissue (VAT) weight. While they did not exhibit evidence of hepatic inflammation or fibrosis, an increase in hepatic lipid content was observed. This was accompanied by an increase in the hepatic expression of genes involved in fatty acid transport and synthesis, as well as fatty acid oxidation. Markers of hepatic inflammation and fibrosis were unaffected by adipocyte VDR ablation. Consistent with the increase in VAT weight in the Adipoq-Cre; VDRflox/flox mice, higher levels of transcripts encoding adipogenesis-related genes were observed in VAT. In contrast to other models of impaired vitamin D signaling studied in the setting of a high-fat or "Western" diet, the Adipoq-Cre; VDRflox/flox mice do not exhibit hepatic inflammation or fibrosis. These findings suggest that the adipocyte VDR regulates hepatic lipid accumulation, but in the absence of obesity or a high-fat diet, is not required to prevent hepatic inflammation or fibrosis.

Osteitis Fibrosis Cystica: Classical Case Report of an Uncommon Presentation in a Young Female.

Osteitis fibrosa cystica (OFC) is a skeletal disease related to long standing, end-stage hyperparathyroidism. However, nowadays hypercalcemia due to primary or secondary hyperparathyroidism can often be detected early by laboratory screening and imaging modalities; consequentially the frequency of osteitis fibrosa cystica has drastically declined. OFC, also termed as Brown tumor, can mimic primary bone tumors clinically, which often leads to misdiagnosis and inappropriate management. Moreover due to its rarity, it is usually not considered initially in the differential diagnosis of bony tumors. Case presentation: This is the case of a 19-year-old female, who presented with pain over the left ankle region for 3 months. The biochemical screening revealed a picture consistent with primary hyperparathyroidism and the radiologically proven to be left inferior parathyroid adenoma. She underwent excision of the primary parathyroid adenoma, and gradual regression of symptoms was noted postoperatively. Osteitis fibrosa cystica is a rare manifestation of hyperparathtyroidism, which has become a forgotten entity lately due to early identification of hypercalcaemia by modern techniques. A delay in the diagnosis of parathyroid adenoma results in manifestations that can be avoided. The diagnosis of OFC requires a high degree of clinical suspicion. When hypersecretion of PTH is corrected, spontaneous regression of the lesion is expected.

Hyperglycemia and steroid use increase the risk of rhino-orbito-cerebral mucormycosis regardless of COVID-19 hospitalization: Case-control study, India.

BACKGROUND: In the ongoing COVID-19 pandemic, an increased incidence of ROCM was noted in India among those infected with COVID. We determined risk factors for rhino-orbito-cerebral mucormycosis (ROCM) post Coronavirus disease 2019 (COVID-19) among those never and ever hospitalized for COVID-19 separately through a multicentric, hospital-based, unmatched case-control study across India. METHODS: We defined cases and controls as those with and without post-COVID ROCM, respectively. We compared their socio-demographics, co-morbidities, steroid use, glycaemic status, and practices. We calculated crude and adjusted odds ratio (AOR) with 95% confidence intervals (CI) through logistic regression. The covariates with a p-value for crude OR of less than 0·20 were considered for the regression model. RESULTS: Among hospitalised, we recruited 267 cases and 256 controls and 116 cases and 231 controls among never hospitalised. Risk factors (AOR; 95% CI) for post-COVID ROCM among the hospitalised were age 45-59 years (2·1; 1·4 to 3·1), having diabetes mellitus (4·9; 3·4 to 7·1), elevated plasma glucose (6·4; 2·4 to 17·2), steroid use (3·2; 2 to 5·2) and frequent nasal washing (4·8; 1·4 to 17). Among those never hospitalised, age ≥ 60 years (6·6; 3·3 to 13·3), having diabetes mellitus (6·7; 3·8 to 11·6), elevated plasma glucose (13·7; 2·2 to 84), steroid use (9·8; 5·8 to 16·6), and cloth facemask use (2·6; 1·5 to 4·5) were associated with increased risk of post-COVID ROCM. CONCLUSIONS: Hyperglycemia, irrespective of having diabetes mellitus and steroid use, was associated with an increased risk of ROCM independent of COVID-19 hospitalisation. Rational steroid usage and glucose monitoring may reduce the risk of post-COVID.

Triage of potential COVID-19 patients from chest X-ray images using hierarchical convolutional networks.

The current COVID-19 pandemic has motivated the researchers to use artificial intelligence techniques for a potential alternative to reverse transcription-polymerase chain reaction due to the limited scale of testing. The chest X-ray (CXR) is one of the alternatives to achieve fast diagnosis, but the unavailability of large-scale annotated data makes the clinical implementation of machine learning-based COVID detection difficult. Another issue is the usage of ImageNet pre-trained networks which does not extract reliable feature representations from medical images. In this paper, we propose the use of hierarchical convolutional network (HCN) architecture to naturally augment the data along with diversified features. The HCN uses the first convolution layer from COVIDNet followed by the convolutional layers from well-known pre-trained networks to extract the features. The use of the convolution layer from COVIDNet ensures the extraction of representations relevant to the CXR modality. We also propose the use of ECOC for encoding multiclass problems to binary classification for improving the recognition performance. Experimental results show that HCN architecture is capable of achieving better results in comparison with the existing studies. The proposed method can accurately triage potential COVID-19 patients through CXR images for sharing the testing load and increasing the testing capacity.

Parathyroid hormone signaling in mature osteoblasts/osteocytes protects mice from age-related bone loss.

Aging is accompanied by osteopenia, characterized by reduced bone formation and increased bone resorption. Osteocytes, the terminally differentiated osteoblasts, are regulators of bone homeostasis, and parathyroid hormone (PTH) receptor (PPR) signaling in mature osteoblasts/osteocytes is essential for PTH-driven anabolic and catabolic skeletal responses. However, the role of PPR signaling in those cells during aging has not been investigated. The aim of this study was to analyze the role of PTH signaling in mature osteoblasts/osteocytes during aging. Mice lacking PPR in osteocyte (Dmp1-PPRKO) display an age-dependent osteopenia characterized by a significant decrease in osteoblast activity and increase in osteoclast number and activity. At the molecular level, the absence of PPR signaling in mature osteoblasts/osteocytes is associated with an increase in serum sclerostin and a significant increase in osteocytes expressing 4-hydroxy-2-nonenals, a marker of oxidative stress. In Dmp1-PPRKO mice there was an age-dependent increase in p16Ink4a/Cdkn2a expression, whereas it was unchanged in controls. In vitro studies demonstrated that PTH protects osteocytes from oxidative stress-induced cell death. In summary, we reported that PPR signaling in osteocytes is important for protecting the skeleton from age-induced bone loss by restraining osteoclast's activity and protecting osteocytes from oxidative stresses.

Potential for therapeutic targeting of tumor stem cells.

Recent developments in isolation and characterization of tumor stem cells (TSCs) have opened new possibilities for developing TSC-targeted therapies. Extensive efforts have been made to ascertain markers of TSCs, including cell surface, enzymatic, gene expression profile, and functional markers. These markers and the technologies used to identify and isolate TSCs are discussed in this review. TSC characteristics, such as quiescence, multidrug resistance, enhanced DNA repair ability, and anti-apoptotic mechanisms, and various features of the in vivo niche, which may make them resistant to conventional therapy, are also discussed here. The increasing understanding of aberrantly expressed molecules and signaling pathways in TSCs may provide the foundation for design of therapeutic strategies for TSC ablation.

Novel infectivity-enhanced oncolytic adenovirus with a capsid-incorporated dual-imaging moiety for monitoring virotherapy in ovarian cancer.

We sought to develop a cancer-targeted, infectivity-enhanced oncolytic adenovirus that embodies a capsid-labeling fusion for noninvasive dual-modality imaging of ovarian cancer virotherapy. A functional fusion protein composed of fluorescent and nuclear imaging tags was genetically incorporated into the capsid of an infectivity-enhanced conditionally replicative adenovirus. Incorporation of herpes simplex virus thymidine kinase (HSV-tk) and monomeric red fluorescent protein 1 (mRFP1) into the viral capsid and its genomic stability were verified by molecular analyses. Replication and oncolysis were evaluated in ovarian cancer cells. Fusion functionality was confirmed by in vitro gamma camera and fluorescent microscopy imaging. Comparison of tk-mRFP virus to single-modality controls revealed similar replication efficiency and oncolytic potency. Molecular fusion did not abolish enzymatic activity of HSV-tk as the virus effectively phosphorylated thymidine both ex vivo and in vitro. In vitro fluorescence imaging demonstrated a strong correlation between the intensity of fluorescent signal and cytopathic effect in infected ovarian cancer cells, suggesting that fluorescence can be used to monitor viral replication. We have in vitro validated a new infectivity-enhanced oncolytic adenovirus with a dual-imaging modality-labeled capsid, optimized for ovarian cancer virotherapy. The new agent could provide incremental gains toward climbing the barriers for achieving conditionally replicated adenovirus efficacy in human trials.

Bacteriological Profile in Attico-antral type of Chronic Suppurative Otitis Media.

Chronic suppurative otitis media is defined as a chronic inflammation of the middle ear cleft, which presents with recurrent ear discharge through a tympanic membrane perforation. The purpose of this study was to find pattern of bacteriology in patients of atticoantral type of chronic suppurative otitis media as it will help the clinician to decide the effective antibiotics to be prescribed. This prospective and observational study was conducted in the Department of ENT in collaboration with Department of Microbiology, Government Medical College and Hospital, Chandigarh. The ear discharge specimen of all patients meeting the inclusion criteria were collected and sent for microbial examination. Culture positive samples were subjected to antibiotic sensitivity. A total of one hundred ears (mean age 27.33 years) clinically diagnosed with chronic suppurative otitis media, atticoantral type were included in this study based on the preset inclusion and exclusion. The male: female ratio in our patients was 0.94:1. Ninety-seven (96.9%) patients had unilateral disease, while 3 (3.1%) patients had bilateral disease. Twenty-eight percent of the total samples were sterile. The most common bacteria isolated were Pseudomonas aeruginosa (27.1%), Methicillin sensitive Staphylococcus aureus (23.3%) and Proteur mirabilis (6.5%). was sensitive to polymyxin B (100%) followed by ciprofloxacin (46.4%), neomycin (42.9%) and gentamicin (42.9%). Polymyxin B is the most effective antibiotic against the cultured bacteria followed by gentamicin, ciprofloxacin and neomycin.

Spindle cell lipoma mimicking pleomorphic adenoma: A diagnostic challenge on cytology.

Spindle cell lipoma (SCL) is a benign neoplasm of mature adipose tissue mostly located in the neck, back, and shoulder region. It is composed of a variable admixture of adipocytes, benign spindle cells, and collagen fibres. While the histopathologic features of SCL are quite characteristic and well described, a cytologic diagnosis of SCL might be challenging. We present a case of a 36-year-old female with a swelling in the left preauricular region since last 6 mo. On fine needle aspiration, a diagnosis of lipomatous pleomorphic adenoma (PA) was rendered because of the presence of benign spindle-shaped cells, adipocytes, and abundant myxoid material. However, on histopathologic examination, the diagnosis was SCL which was confirmed by immunohistochemistry. Preauricular region is a rare site of occurrence of SCL. An acquaintance with its varied cytomorphologic features and a knowledge of its unusual sites of occurrence is essential to prevent its misdiagnosis as other myxoid benign and malignant spindle cell lesions.

TG-interacting factor 1 (Tgif1)-deficiency attenuates bone remodeling and blunts the anabolic response to parathyroid hormone.

Osteoporosis is caused by increased bone resorption and decreased bone formation. Intermittent administration of a fragment of Parathyroid hormone (PTH) activates osteoblast-mediated bone formation and is used in patients with severe osteoporosis. However, the mechanisms by which PTH elicits its anabolic effect are not fully elucidated. Here we show that the absence of the homeodomain protein TG-interacting factor 1 (Tgif1) impairs osteoblast differentiation and activity, leading to a reduced bone formation. Deletion of Tgif1 in osteoblasts and osteocytes decreases bone resorption due to an increased secretion of Semaphorin 3E (Sema3E), an osteoclast-inhibiting factor. Tgif1 is a PTH target gene and PTH treatment failed to increase bone formation and bone mass in Tgif1-deficient mice. Thus, our study identifies Tgif1 as a novel regulator of bone remodeling and an essential component of the PTH anabolic action. These insights contribute to a better understanding of bone metabolism and the anabolic function of PTH.

An adenoviral platform for selective self-assembly and targeted delivery of nanoparticles.

Metallic nanoparticles (NPs) can be used for the diagnosis, imaging, and therapy of tumors and cardiovascular disease. However, targeted delivery of NPs to specific cells remains a major limitation for clinical realization of these potential treatment options. Herein, a novel strategy for the specific coupling of NPs to a targeted adenoviral (Ad) platform to deliver NPs to specific cells is defined. Genetic manipulation of the gene-therapy vector is combined with a specific chemical coupling strategy. In particular, a high-affinity interaction between a sequence of six-histidine amino acid residues genetically incorporated into Ad capsid proteins and nickel(II) nitrilotriacetic acid on the surface of gold NPs is employed. The selective self-assembly of gold NPs and Ad vectors into multifunctional platforms does not negatively affect the targeting of Ad to specific cells. This opens the possibility of using Ad vectors for targeted NP delivery, thereby providing a new type of combinatorial approach for the treatment of diseases that involves both nanotechnology and gene therapy.

Osteocyte-Secreted Wnt Signaling Inhibitor Sclerostin Contributes to Beige Adipogenesis in Peripheral Fat Depots.

Cells of the osteoblast lineage are increasingly identified as participants in whole-body metabolism by primarily targeting pancreatic insulin secretion or consuming energy. Osteocytes, the most abundant bone cells, secrete a Wnt-signaling inhibitor called sclerostin. Here we examined three mouse models expressing high sclerostin levels, achieved through constitutive or inducible loss of the stimulatory subunit of G-proteins (Gsα in mature osteoblasts and/or osteocytes). These mice showed progressive loss of white adipose tissue (WAT) with tendency toward increased energy expenditure but no changes in glucose or insulin metabolism. Interestingly beige adipocytes were increased extensively in both gonadal and inguinal WAT and had reduced canonical ß-catenin signaling. To determine if sclerostin directly contributes to the increased beige adipogenesis, we engineered an osteocytic cell line lacking Gsα which has high sclerostin secretion. Conditioned media from these cells significantly increased expression of UCP1 in primary adipocytes, and this effect was partially reduced after depletion of sclerostin from the conditioned media. Similarly, treatment of Gsα-deficient animals with sclerostin-neutralizing antibody partially reduced the increased UCP1 expression in WAT. Moreover, direct treatment of sclerostin to wild-type mice significantly increased UCP1 expression in WAT. These results show that osteocytes and/or osteoblasts secrete factors regulating beige adipogenesis, at least in part, through the Wnt-signaling inhibitor sclerostin. Further studies are needed to assess metabolic effects of sclerostin on adipocytes and other metabolic tissues. © 2016 American Society for Bone and Mineral Research.

Combination of viral biology and nanotechnology: new applications in nanomedicine.

Viruses are well known for their ability to cause disease, but their beneficial usefulness as vectors for gene therapy have been noted as well. As an extension of their use in a gene therapy context, their combination with nanotechnology is starting to benefit many areas of science and medicine. These include nanofabrication and medical diagnostics, to name a few, as well as viro-nanotherapy, here defined as the combination of viral biology with nanotechnology to create new therapeutic avenues to treat disease. This review provides examples of areas wherein viruses in combination with nanotechnology are being used to either advance scientific knowledge or accelerate the development of new diagnostics and therapeutics for human pathological conditions.

PTH Signaling in Osteoprogenitors Is Essential for B-Lymphocyte Differentiation and Mobilization.

Cells of the osteoblast lineage provide critical support for B lymphopoiesis in the bone marrow (BM). Parathyroid hormone (PTH) signaling in osteoblastic cells through its receptor (PPR) is an important regulator of hematopoietic stem cells; however, its role in regulation of B lymphopoiesis is not clear. Here we demonstrate that deletion of PPR in osteoprogenitors results in a significant loss of trabecular and cortical bone. PPR signaling in osteoprogenitors, but not in mature osteoblasts or osteocytes, is critical for B-cell precursor differentiation via IL-7 production. Interestingly, despite a severe reduction in B-cell progenitors in BM, mature B-lymphocytes were increased 3.5-fold in the BM of mice lacking PPR in osteoprogenitors. This retention of mature IgD(+) B cells in the BM was associated with increased expression of vascular cell adhesion molecule 1 (VCAM1) by PPR-deficient osteoprogenitors, and treatment with VCAM1 neutralizing antibody increased mobilization of B lymphocytes from mutant BM. Our results demonstrate that PPR signaling in early osteoblasts is necessary for B-cell differentiation via IL-7 secretion and for B-lymphocyte mobilization via VCAM1.