bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a Novel Tetracycline-Inducible Kiss1-Cre Mouse Line for Temporally Controlled Gene Deletion in Kisspeptin Neurons
Authors: Negron Ariel L , Levine Jon E , Radovick Sally 
Published: May 2021

Abstract
The tetracycline (Tet)-controlled inducible system is the most widely used reversible system for transgenic expression in mice. Previously, we generated a GnRH-CreTeR mouse model, using a first-generation Tet-inducible system to temporally induce expression of Cre recombinase in GnRH neurons. Recently, the Tet-inducible system has undergone several modifications to significantly reduce previous limitations that include leaky background expression and lower sensitivity to tetracycline induction. Therefore, we have developed a novel mouse model bearing a Tet-inducible kisspeptin-Cre allele (iKiss-Cre mouse) that will enable temporal control over the selective deletion of genes from Kiss1 neurons. This temporally controlled gene deletion will eliminate a longstanding technical limitation of conventional steroid receptor knockout models in which steroid regulation of the axis is confounded by steroid developmental and organizational effects in the reproductive axis. Two mouse lines were generated. The first line targets kisspeptin neurons with a third generation Tet-inducible reverse tetracycline transactivator (rtTA, Tet-On 3G) expressed under the control of the Kiss1 allele. Using CRISPR-Cas9 technology, we inserted a cassette containing an internal ribosome entry site (IRES) sequence followed by the rtTA downstream of the Kiss1 coding region as was previously done using Cre recombinase. Transcription of the recombinant Kiss1 allele yields a bicistronic messenger RNA, from which both kisspeptin and rtTA are independently translated. The second mouse line, TRE-Cre mice, was constructed to express Cre recombinase under control of the PTRE3G promoter. The PTRE3G promoter is bidirectional to allow simultaneous monitoring of Cre expression and a second florescent protein reporter (ZsGreen1). The Kiss1-rtTA only binds to and activates the PTRE3G promoter in the presence of doxycycline (an analog of tetracycline). Offspring from breeding of these mouse lines, iKiss-Cre, result in a system capable of generating Tet-induced expression of Cre recombinase in kisspeptin neurons. In order to document specificity and sensitivity of this system, we performed immunofluorescent staining and observed colocalization of kisspeptin with Cre recombinase in brain sections of iKiss-Cre mice only after doxycycline treatment. We will use this model to investigate negative feedback actions of E2 on the adultpulse generator after E2 exerts its organizational actions on maturing kisspeptin neurons. We expect that this mouse model will become a major tool used by the neuroendocrine community and serve as proof of principle for development of similar inducible knockout models employing the current generation of inducible methodologies.
MIF Inhibition Suppresses Cell Viability and Induces Apoptosis via the ATF4-CHOP Pathway in Mouse Pituitary AtT-20 Cells
Authors: Wang Jason , Satou Motoyasu , Tateno Tae , Willette Sarah , Yang Rui Zhe , Kitayoshi Fumika , Teramachi Mariko , Sugimoto Hiroyuki , Chik Constance L , Tateno Toru 
Published: May 2021

Abstract
Cushing’s disease (CD) is characterized by cortisol overproduction due to ACTH hypersecretion from a pituitary tumour (PT). With an incidence of approximately 1.2 to 2.4 cases per million per year, CD patients have higher rates of morbidity and mortality than the general population. Surgical management is currently the first therapeutic option. However, remission rates vary between studies, and patients may suffer from complications caused by hormonal abnormalities from remnant PT tissues, the surgery itself, as medical treatment options are limited. Macrophage migratory inhibitory factor (MIF) is a cytokine expressed in various tumors, including ACTH-producing PTs, and has been found to play a crucial role in tumorigenesis. Previous studies demonstrate that MIF regulates cell growth via the signal transducer and activator of transcription 3 (STAT3) pathway, the mammalian target of rapamycin (mTOR) pathway, and autophagy. Together, these indicate MIF as a potential therapeutic target for PTs. However, the role of MIF in ACTH-producing PTs remains unknown. Using mouse ACTH-producing PT cells, AtT-20 cells as a model, we established that MIF overexpression led to increased cell growth. In contrast, pharmacological MIF inhibition by 4-iodo-6-phenylpyrimidine (4-IPP) and (S,R)-3-(4-Hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid (ISO-1) and genetic MIF downregulation by siRNA both suppressed cell viability and induced apoptosis, suggesting an anti-apoptotic role of MIF. Genetic MIF downregulation also increased the expression of apoptosis-inducible genes such as activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP), and reduced ACTH production. However, pharmacological MIF inhibition had no effect on ACTH production, which suggests that the mechanism of pharmacological MIF inhibition may be different from MIF downregulation. Neither MIF upregulation nor downregulation affected cell signalling pathways such as the STAT3 pathway, the mTOR pathway, or autophagy. Our findings suggest that MIF inhibition can be a viable therapeutic approach for ACTH-producing PTs.
ScRNA-seq Reveals a Role of Mammary Luminal Epithelium in Adipocyte Adaptations
Authors: Santos Luis , Arneson Douglas , Chella Krishnan Karthickeyan , Ahn In Sook , Diamante Graciel , Cely Ingrid , Butte Atul , Lusis Aldons , Yang Xia , Rajbhandari Prashant 
Published: May 2021

Abstract
Almost four decades of research suggest a dynamic role of ductal epithelial cells in adipocyte adaptation in mammary gland white adipose tissue (mgWAT), but factors that mediate such communication are not known. Here, we identify a complex intercellular crosstalk in mgWAT revealed by single-cell RNA-seq (scRNA-seq) and comprehensive data analysis suggest that epithelial luminal cells during cold exposure undergo major transcriptomic changes that lead to the expression of an array of genes that encode for secreted factors involved in adipose metabolism such as Adropin (Enho), neuregulin 4 (Nrg4), angiopoietin-like 4 (Angptl4), lipocalin 2 (Lcn2), milk fat globule-EGF factor 8 (Mfge8), Insulin-like growth factor-binding protein 1 (Igfbp1), and haptoglobin (Hp). To define the mammary epithelial secretome, we coin the phrase “mammokines”. We validated our cluster annotations and cluster-specific transcriptomics using eight different adipose scRNA-seq datasets including Tabula Muris and Tabula Muris Senis. In situ mRNA hybridization and ex vivo isolated mgWAT luminal cells show highly localized expression of mammokines in mammary ducts. Trajectory inference demonstrates that cold-exposed luminal cells have similar transcriptional profiles to lactation post-involution (PI), a phase defined by reappearance and maintenance of adipocytes in the mammary gland. Concomitantly, we found that under cold exposure female mgWAT maintains more adipogenic and less thermogenic potential than male scWAT and ex vivo removal of luminal epithelial cells from mgWAT markedly potentiates beige adipocyte differentiation. Conditioned media from isolated mammary epithelial cells treated with isoproterenol suppressed thermogenesis in differentiated beige/brown adipocytes and treatment of beige/brown differentiated adipocyte with mammokine LCN2 suppresses thermogenesis and increases adipogenesis. Finally, we find that mice lacking LCN2 show markedly higher cold-dependent thermogenesis in mgWAT than controls, and reconstitution of LCN2 in the mgWAT of LCN2 knockout mice promotes inhibition of thermogenesis. These results show a previously unknown role of mammary epithelium in adipocyte metabolism and suggest a potentially redundant evolutionary role of mammokines in maintaining mgWAT adiposity during cold exposure. Our data highlight mammary gland epithelium as a highly active metabolic cell type and mammokines could have broader implications in mammary gland physiology and lipid metabolism.
Recessive PRDM13 Mutations Result in Hypogonadotropic Hypogonadism and Cerebellar Hypoplasia
Authors: Oleari Roberto , Whittaker Danielle , Gregory Louise Cheryl , Albert Basson , Cariboni Anna Maria , Dattani Mehul Tulsidas 
Published: May 2021

Abstract
PRDM13 (PR Domain containing 13) is a putative chromatin modifier and transcriptional regulator that functions downstream of the transcription factor PTF1A. Here, we report a novel, recessive syndrome associated with PRDM13 mutation. Patients exhibited intellectual disability, ataxia with cerebellar hypoplasia, scoliosis and delayed puberty with hypogonadotropic hypogonadism (HH). We investigated the development of hypothalamic neurons and the cerebellum in mice homozygous for a Prdm13 mutant allele. Cerebellar hypoplasia was evident, but male gonadal development appeared unaffected in these mutants. As PTF1A has been linked to early GABAergic neuronal cell fate regulation in the spinal cord, we examined GABAergic neuron progenitor development in the hypothalamus and cerebellum. A significant reduction in the number of Kisspeptin neurons in the hypothalamus and PAX2+ progenitors emerging from the cerebellar ventricular zone was observed. The latter was accompanied by ectopic expression of the glutamatergic lineage marker TLX3. Together, these findings identify PRDM13 as a critical regulator of GABAergic cell fate during neurodevelopment, providing a mechanistic explanation for the co-occurrence of HH and cerebellar hypoplasia in this syndrome. To our knowledge, this is the first evidence linking disrupted regulation of Kiss1 neurons to CHH in humans.
Spatial Transcriptomics for the Analysis of Human Pituitary Development
Authors: Matsumoto Ryusaku , Kabata Mio , Suga Hidetaka , Yamamoto Takuya 
Published: May 2021

Abstract
The pituitary develops from oral ectoderm in contact with the adjacent hypothalamus. However, the precise mechanisms underlying pituitary development in concert with plural tissues are not fully understood, especially in human. A protocol to induce pituitary cells from human induced pluripotent stem cells (hiPSCs) has been established and applied to study pituitary development and disorders. In the method, oral ectoderm and hypothalamus are induced in one organoid, which enables recapitulation of the interactions between these tissues during embryonic development. It leads to self-organization of pituitary cells. Recently, spatial transcriptome technology has been developed and is suitable for the analysis of tissue interactions. Here, we utilized spatial transcriptomics to analyze pituitary organoids, especially focusing on the mechanisms regulating pituitary progenitor cell differentiation. Spatial transcriptomics revealed that the organoids consisted of several cell populations including hypothalamus, oral ectoderm, neural retina, and cortex neuron cells. Pituitary progenitor cells, characterized by the upregulation of LHX3, were included as part of the oral ectoderm population. Further analysis of the population identified human pituitary progenitor-specific genes including many causal genes for congenital hypopituitarism (CPH). Finally, using spatially resolved gene expression data, we examined the hypothalamic population that was in contact with pituitary progenitor cells and identified hypothalamic factors that might regulate progenitor cell differentiation in a paracrine manner. The genes upregulated in the pituitary progenitor and neighboring hypothalamus cell populations are potential causal gene candidates for CPH. In conclusion, spatial transcriptomics provides a novel platform to analyze tissue interaction networks during human pituitary development.
A Case of Inappropriate Antidiuretic Hormone Secretion Syndrome Associated With COVID-19 Pneumonia Treated With Boluses of Hypertonic Saline for Reversal of Symptomatic Hyponatremia
Authors: Miranda Gonzalo Francisco , Rodríguez Karen Evelyn Ramos , Research Clinical 
Published: May 2021

Abstract
Hyponatremia is the most common electrolyte disorder, which can occur in outpatients and hospitalized patients, so both first-contact doctors and specialists must keep up-to-date on the prevention, recognition, diagnosis and management of this complication.
A 68-year-old male patient presents to Dos de Mayo National Hospital Emergency Department. He was diagnosed as COVID-19 pneumonia and hospitalized for management of acute respiratory failure. The patient had neurological impairment associated with poor oral tolerance. Initial laboratory examinations were C-reactive protein in 363.5 mg/L, serum sodium of 128.42 mmol/L and urine sodium was 83 meq/L. Osmolality in plasma was 266.15 mOsm/Kg and urine osmolality was 420 mOsm/Kg. Thyroid function tests as well as cortisol levels were in normal range. Our patient was diagnosed as SIAD by hyponatremia, osmolality in plasma &lt;275 mOsm / kg, urine osmolality &gt; 100 mOsm / kg, urine sodium &gt; 40 mEq / l, euvolemic state and exclusion of cortisol and thyroid hormone deficiency. Treatment of hyponatremia was initiated and rapidly elevate plasma sodium by 4 meq/l in the first 6 hours. There was clinical improvement. Blood sodium levels ranged from 115 to 135 mmol/L with bolus therapy of hypertonic solutions in 72 hours. Intravenous boluses of hypertonic saline should be administered to rapidly elevate plasma sodium by 4 to 6 mEq/L in the first 6 hours. The data shows that fluid bolus therapy is more effective in acutely elevating plasma sodium than traditional low-dose hypertonic saline infusion that may lead to avoidable deaths according to recent guidelines. In this case a strategy based with bolus therapy for reversal of hyponatremia was used effectively.
A number of cases of COVID-19 pneumonia are associated with SIAD. The presence of SIAD could be a clue to diagnosing COVID-19. SIAD is a major complication of COVID-19 and could be the first and only manifestation. In cases of SIAD without a clear etiology we should suspect COVID-19 in a patient with respiratory distress in the current pandemic.
Syndrome of inappropiate antidiuresis (SIAD) should be assessed in every patient with COVID-19 as their treatment and early identification decreases mortality. The association between COVID-19 pneumonia and SIAD should be further identified, requiring doctors to be aware of this condition. Additional studies are required to determine the incidence and pathogenesis of SIAD in patients with COVID-19.
Acknowledging the Blind Spot of Bitemporal Hemianopsia: Keeping a High Index of Suspicion for Pituitary Macroadenomas in Uncommon Presentations
Authors: Raco Joseph , Macias Maria , Jain Rohit 
Published: May 2021

Abstract
Background: Hyperglycemia in patients with type 2 diabetes mellitus commonly manifests as symptoms of polyuria, polydipsia, fatigue, and weight loss as a result of insulin resistance. In cases of severe hyperglycemia, patients may also experience visual disturbances and dizziness as a result of swelling of the lens and dehydration respectively. These symptoms are not generally accompanied by gait disturbance or fixed, focal deficits on neurological examination. As such, symptoms such as double vision, peripheral field vision loss, cranial nerve deficits, or significant unsteadiness may warrant a more extensive neurologic workup rather than simply attributing all symptoms to hyperglycemia. Clinical Case: A 57-year-old woman presented to the emergency department with five days of fatigue, polyuria, polydipsia and pre-syncope associated with dizziness. She also described double vision in her peripheral visual fields and episodes of gait disturbances causing her to have to lower herself to the ground on multiple occasions, without loss of consciousness. Her neurologic examination demonstrated mildly ataxic finger-to-nose testing and concern for peripheral field vision loss. Intake lab work revealed a blood glucose of 725 mg/dL and a hemoglobin A1C of 13.4%. Initial neuroimaging with computed tomography was unremarkable. Though her symptoms were thought to be due to severe hyperglycemia, an MRI brain was obtained due to abnormal neurologic examination. MRI demonstrated a 1.9 cm pituitary macroadenoma abutting the optic chiasm with concern for hemorrhage. Subsequent lab evaluation determined the pituitary macroadenoma non-functional with TSH, free T4, free T3, AM cortisol, AM ACTH, and prolactin all within normal limits. Her hyperglycemia was treated with insulin with clinical improvement in all regards except visual symptoms. She was deemed safe for discharge with neurosurgical follow-up regarding surgical removal of her macroadenoma. Conclusion: Although hyperglycemia may present with broad symptoms including vague neurologic symptoms, it is critical to keep a broad differential diagnosis when atypical symptoms such as persistent vision changes and gait disturbances are present, especially after improvement in glycemic control has been obtained. A low threshold should be held for obtaining neuroimaging, as it is prudent to rule-out life-threatening causes of neurologic dysfunction.
Antipsychotic Medication Use Delays Diagnosis of Acromegaly
Authors: Rosner Matthew Norman , Rao Ambika 
Published: May 2021

Abstract
Background: Elevated prolactin level from use of antipsychotic medication masked the diagnosis of acromegaly.
Clinical Case: A 29-year old woman presented with galactorrhea, metrorrhagia, menorrhagia, 50 lb. weight gain, hirsutism, insomnia, and breast engorgement for one year. She was evaluated by gynecology and treated with a combination estrogen/progesterone pill, and then switched to a patch. For several years she had been on haloperidol and various phenothiazine medications for paranoid schizophrenia. Initial evaluation included elevated prolactin level of 94.46 ng/ml (5.2-26.25 ng/mL). Differential diagnosis of PCOS versus medication induced hyperprolactinemia was considered. Patient was started on metformin and referred to nutrition for weight management. MRI scan ordered by her primacy care physician revealed a 13 x 12 x 10 mm pituitary mass with intrinsic mixed density and homogenous enhancement. Visual field testing revealed no deficits. On further testing: IgF-1 432 ng/ml (53-331 ng/ml), TSH 0.85 uIU/mL (0.35-4.94 IUI/ml), ACTH 22 pg/mL (6-50 pg/ml), cortisol 7.7 ug/dl (4.3-22.4 mcg/dl). Differential diagnosis of stalk compression versus functioning adenoma was considered and cabergoline was initiated after she was seen by neurosurgery and declined surgical intervention. She was noncompliant with cabergoline. Surveillance over next two years showed no increase in tumor size on MRI or change in hormone levels. She was then lost to follow up for a year and presented with increased diaphoresis and swelling of her hands. Prolactin three years after diagnosis decreased to 50.59 ng/mL and IgF-1 to 639 ng/ml. She was then referred to endocrinology. Oral glucose tolerance test did not suppress growth hormone below 1.9 ng/ml. Her cortisol suppressed to 0.1 mcg/dl with 1 mg dexamethasone. A diagnosis of Acromegaly was confirmed. She was referred for neurosurgical evaluation and scheduled for transsphenoidal hypophysectomy. She failed to arrive for scheduled surgery. Repeat MRI five years after diagnosis showed a 13 x 16 x 20 mm pituitary adenoma with IgF-1 level of 1011 ng/ml. Octreotide LAR 20 mg monthly was initiated. After two months of injections: prolactin 69.36 ng/ml, IgF-1 778 ng/ml. Repeat visual field testing showed mild constriction in the superior and inferior temporal fields. Patient was scheduled for MRI and surgical procedure but was lost to follow-up.
Conclusion: Elevation in prolactin levels in conjunction with antipsychotic medications and diagnosis of schizophrenia masked the early diagnosis of Acromegaly in this patient.
Cerebrospinal Fluid Leak After Medical Management of Prolactinoma
Authors: Pechman Amanda , Manavalan Anjali , Kishore Preeti 
Published: May 2021

Abstract
Introduction: Dopaminergic agonists such as cabergoline are commonly used to treat prolactinomas, and often lead to significant adenoma shrinkage. Rarely, macroprolactinomas may invade the sphenoid sinus and pose a therapeutic challenge, as treatment with dopamine agonists and subsequent tumor shrinkage can lead to a cerebrospinal fluid (CSF) leak.
Clinical Case: A 32-year-old female with no prior medical history presented to the emergency room of an outside hospital for headaches and visual changes. MRI demonstrated a 4.3 x 4.0 x 3.0 cm sellar mass with extension into the right cavernous sinus and sphenoid sinus, and prolactin was elevated to 1,859 ng/ml (3.4 - 21.4). Cabergoline was initiated at a dose of 0.25 mg twice a week with a decrease in her prolactin to 646 ng/ml one month later. Six months after initiation of therapy she transferred her care to our institution and presented for a routine endocrinology visit. She complained of rhinorrhea worse when upright that had begun two weeks prior to this encounter. Urgent MRI of the sella revealed an interval decrease in the size of the sellar mass to 2.1 x 2.7 x 1.5 cm and a fluid collection extending from the sella turcica to the left sphenoid sinus consistent with a CSF leak, and labs showed a prolactin level of 169 ng/ml. Cabergoline was discontinued and the patient was admitted to the hospital for treatment with antibiotics and acetazolamide. She underwent lumbar drain placement while awaiting definitive surgical management, which was delayed due to the COVID-19 pandemic. While off cabergoline, the sellar mass increased in size and her prolactin rose to 1,449 ng/ml, with no effect on the optic chiasm and visual fields. Three months later, she underwent transsphenoidal debulking of the pituitary mass with repair of the sellar floor and removal of lumbar drain. Her postoperative course was uncomplicated and she resumed cabergoline 0.25 mg twice weekly. A prolactin measured two weeks postoperatively was 337 ng/ml. Tumor histopathology revealed a 1.3 x 0.4 x 0.3 cm pituitary adenoma. Immunohistochemistry stained positive for chromogranin A, synaptophysin, and prolactin only. An MRI of the sella and prolactin level will be repeated at her next endocrinology visit.
Conclusions: CSF leak is a rare but serious complication from tumor shrinkage after medical management of large invasive prolactinomas, and patients with such tumors should be monitored closely for its development. CSF leaks can increase a patient’s risk for meningitis and subsequent morbidity and mortality. The management of patients with large prolactinomas with local invasion should involve a multidisciplinary approach for decision making, extensive patient education, and close follow up in order to identify and treat a CSF leak should it develop.