Publications search

Found 37684 matches. Displaying 5231-5240
Soteriou D, Kostic L, Sedov E, Yosefzon Y, Steller H, Fuchs Y
Show All Authors

Isolating Hair Follicle Stem Cells and Epidermal Keratinocytes from Dorsal Mouse Skin

JOVE-JOURNAL OF VISUALIZED EXPERIMENTS 2016 APR; ?(110):? Article e53931
The hair follicle (HF) is an ideal system for studying the biology and regulation of adult stem cells (SCs). This dynamic mini organ is replenished by distinct pools of SCs, which are located in the permanent portion of the HF, a region known as the bulge. These multipotent bulge SCs were initially identified as slow cycling label retaining cells; however, their isolation has been made feasible after identification of specific cell markers, such as CD34 and keratin 15 (K15). Here, we describe a robust method for isolating bulge SCs and epidermal keratinocytes from mouse HFs utilizing fluorescence activated cell-sorting (FACS) technology. Isolated hair follicle SCs (HFSCs) can be utilized in various in vivo grafting models and are a valuable in vitro model for studying the mechanisms that govern multipotency, quiescence and activation.
Hartnett J, Thom B, Kline N
Show All Authors

Caregiver Burden in End-Stage Ovarian Cancer

CLINICAL JOURNAL OF ONCOLOGY NURSING 2016 APR; 20(2):169-173
Background: Caregiver burden associated with caring for women with ovarian cancer has received limited focus. However, these patients often have complex needs, requiring a high level of care at home and imposing substantial burdens on caregivers. Objectives: This pilot study assessed the level of caregiver burden experienced by the primary caregivers of patients with end-stage ovarian cancer and identified variables associated with caregiver burden. Methods: Caregiver burden was assessed using the Caregiver Reaction Assessment. Fifty caregivers completed an anonymous and voluntary survey. Pearson correlations and independent samples t tests were used to analyze data. Findings: Most participants were Caucasian, married or living with a partner, and college graduates, with an annual household income of less than $90,000. Caregiver ages ranged from 29-81 years. Participants agreed most with the self-esteem scale, indicating they had pride in caring for their loved ones. Disrupted schedules and financial problems were the most burdensome factors in providing care. Because financial issues affected caregiver burden, nurses should facilitate interdisciplinary support. Future research is needed to determine the impact of nurse-led interventions to reduce caregiver burden.
Sarkar S, Bi DP, Zhang J, Ren J, Behringer RP, Chakraborty B
Show All Authors

Shear-induced rigidity of frictional particles: Analysis of emergent order in stress space

PHYSICAL REVIEW E 2016 APR 4; 93(4):? Article 042901
Solids are distinguished from fluids by their ability to resist shear. In equilibrium systems, the resistance to shear is associated with the emergence of broken translational symmetry as exhibited by a nonuniform density pattern that is persistent, which in turn results from minimizing the free energy. In this work, we focus on a class of systems where this paradigm is challenged. We show that shear-driven jamming in dry granular materials is a collective process controlled by the constraints of mechanical equilibrium. We argue that these constraints can lead to a persistent pattern in a dual space that encodes the statistics of contact forces and the topology of the contact network. The shear-jamming transition is marked by the appearance of this persistent pattern. We investigate the structure and behavior of patterns both in real space and the dual space as the system evolves through the rigidity transition for a range of packing fractions and in two different shear protocols. We show that, in the protocol that creates homogeneous jammed states without shear bands, measures of shear jamming do not depend on strain and packing fraction independently but obey a scaling form with a packing-fraction-dependent characteristic strain that goes to zero at the isotropic jamming point phi(J). We demonstrate that it is possible to define a protocol-independent order parameter in this dual space, which provides a quantitative measure of the rigidity of shear-jammed states.
Liu Y, Giannopoulou EG, Wen DC, Falciatori I, Elemento O, Allis CD, Rafii S, Seandel M
Show All Authors

Epigenetic profiles signify cell fate plasticity in unipotent spermatogonial stem and progenitor cells

NATURE COMMUNICATIONS 2016 APR; 7(?):? Article 11275
Spermatogonial stem and progenitor cells (SSCs) generate adult male gametes. During in vitro expansion, these unipotent murine cells spontaneously convert to multipotent adult spermatogonial-derived stem cells (MASCs). Here we investigate this conversion process through integrative transcriptomic and epigenomic analyses. We find in SSCs that promoters essential to maintenance and differentiation of embryonic stem cells (ESCs) are enriched with histone H3-lysine4 and -lysine 27 trimethylations. These bivalent modifications are maintained at most somatic promoters after conversion, bestowing MASCs an ESC-like promoter chromatin. At enhancers, the core pluripotency circuitry is activated partially in SSCs and completely in MASCs, concomitant with loss of germ cell-specific gene expression and initiation of embryonic-like programs. Furthermore, SSCs in vitro maintain the epigenomic characteristics of germ cells in vivo. Our observations suggest that SSCs encode innate plasticity through the epigenome and that both conversion of promoter chromatin states and activation of cell type-specific enhancers are prominent features of reprogramming.
Qin LX, Tuschl T, Singer S
Show All Authors

Empirical insights into the stochasticity of small RNA sequencing

SCIENTIFIC REPORTS 2016 APR 7; 6(?):? Article 24061
The choice of stochasticity distribution for modeling the noise distribution is a fundamental assumption for the analysis of sequencing data and consequently is critical for the accurate assessment of biological heterogeneity and differential expression. The stochasticity of RNA sequencing has been assumed to follow Poisson distributions. We collected microRNA sequencing data and observed that its stochasticity is better approximated by gamma distributions, likely because of the stochastic nature of exponential PCR amplification. We validated our findings with two independent datasets, one for microRNA sequencing and another for RNA sequencing. Motivated by the gamma distributed stochasticity, we provided a simple method for the analysis of RNA sequencing data and showed its superiority to three existing methods for differential expression analysis using three data examples of technical replicate data and biological replicate data.
Yapici N, Cohn R, Schusterreiter C, Ruta V, Vosshall LB
Show All Authors

A Taste Circuit that Regulates Ingestion by Integrating Food and Hunger Signals

CELL 2016 APR 21; 165(3):715-729
Ingestion is a highly regulated behavior that integrates taste and hunger cues to balance food intake with metabolic needs. To study the dynamics of ingestion in the vinegar fly Drosophila melanogaster, we developed Expresso, an automated feeding assay that measures individual meal-bouts with high temporal resolution at nanoliter scale. Flies showed discrete, temporally precise ingestion that was regulated by hunger state and sucrose concentration. We identify 12 cholinergic local interneurons (IN1, for "ingestion neurons'') necessary for this behavior. Sucrose ingestion caused a rapid and persistent increase in IN1 interneuron activity in fasted flies that decreased proportionally in response to subsequent feeding bouts. Sucrose responses of IN1 interneurons in fed flies were significantly smaller and lacked persistent activity. We propose that IN1 neurons monitor ingestion by connecting sugar-sensitive taste neurons in the pharynx to neural circuits that control the drive to ingest. Similar mechanisms for monitoring and regulating ingestion may exist in vertebrates.
To improve our understanding of the similarities and differences between neutralizing antibodies elicited by simian-human immunodeficiency virus (SHIV)-infected rhesus macaques and human immunodeficiency virus type 1 (HIV-1)-infected humans, we examined the plasma of 13 viremic macaques infected with SHIVSF162P3N and 85 HIV-1-infected humans with known times of infection. We identified 5 macaques (38%) from 1 to 2 years postinfection (p.i.) with broadly neutralizing antibodies (bnAbs) against tier 2 HIV-1. In comparison, only 2 out of 42 (5%) human plasma samples collected in a similar time frame of 1 to 3 years p.i. exhibited comparable neutralizing breadths and potencies, with the number increasing to 7 out of 21 (30%) after 3 years p.i. Plasma mapping with monomeric gp120 identified only 2 out of 9 humans and 2 out of 4 macaques that contained gp120-reactive neutralizing antibodies, indicating distinct specificities in these plasma samples, with most of them recognizing the envelope trimer (including gp41) rather than the gp120 monomer. Indeed, a total of 20 gp120-directed monoclonal antibodies (MAbs) isolated from a human subject (AD358) and a Chinese rhesus macaque (GB40) displayed no or limited neutralizing activity against tier 2 strains. These isolated MAbs, mapped to the CD4-binding site, the V3 loop, the inner domain, and the C5 region of gp120, revealed genetic similarity between the human and macaque immunoglobulin genes used to encode some V3-directed MAbs. These results also support the use of envelope trimer probes for efficient isolation of HIV-1 bnAbs. IMPORTANCE HIV-1 vaccine research can benefit from understanding the development of broadly neutralizing antibodies (bnAbs) in rhesus macaques, commonly used to assess vaccine immunogenicity and efficacy. Here, we examined 85 HIV-1-infected humans and 13 SHIVSF162P3N-infected macaques for bnAbs and found that, similar to HIV-1-infected humans, bnAbs in SHIV-infected macaques are also rare, but their development might have been faster in some of the studied macaques. Plasma mapping with monomeric gp120 indicated that most bnAbs bind to the envelope trimer rather than the gp120 monomer. In support of this, none of the isolated gp120-reactive monoclonal antibodies (MAbs) displayed the neutralization breadth observed in the corresponding plasma. However, the MAb sequences revealed similarity between human and macaque genes used to encode some V3-directed MAbs. Our study sheds light on the timing and development of bnAbs in SHIV-infected macaques in comparison to HIV-1-infected humans and highlights the use of envelope trimer probes for efficient recovery of bnAbs.
Lim AI, Menegatti S, Bustamante J, Le Bourhis L, Allez M, Rogge L, Casanova JL, Yssel H, Di Santo JP
Show All Authors

IL-12 drives functional plasticity of human group 2 innate lymphoid cells

JOURNAL OF EXPERIMENTAL MEDICINE 2016 APR 4; 213(4):569-583
Group 2 innate lymphoid cells (ILC2) include IL-5- and IL-13-producing CRTh2(+)CD127(+) cells that are implicated in early protective immunity at mucosal surfaces. Whereas functional plasticity has been demonstrated for both human and mouse ILC3 subsets that can reversibly give rise to IFN-gamma-producing ILC1, plasticity of human or mouse ILC2 has not been shown. Here, we analyze the phenotypic and functional heterogeneity of human peripheral blood ILC2. Although subsets of human CRTh2(+) ILC2 differentially express CD117 (c-kit receptor), some ILC2 surface phenotypes are unstable and can be modulated in vitro. Surprisingly, human IL-13(+) ILC2 can acquire the capacity to produce IFN-gamma, thereby generating plastic ILC2. ILC2 cultures demonstrated that IFN-gamma(+) ILC2 clones could be derived and were stably associated with increased T-BET expression. The inductive mechanism for ILC2 plasticity was mapped to the IL-12-IL-12R signaling pathway and was confirmed through analysis of patients with Mendelian susceptibility to mycobacterial disease due to IL-12R beta 1 deficiencies that failed to generate plastic ILC2. We also detected IL-13(+)IFN-gamma(+) ILC2 ex vivo in intestinal samples from Crohn's disease patients. These results demonstrate cytokine production plasticity for human ILC2 and further suggest that environmental cues can dictate ILC phenotype and function for these tissue-resident innate effector cells.
Gleicher N, Kushnir VA, Weghofer A, Barad DH
Show All Authors

The importance of adrenal hypoandrogenism in infertile women with low functional ovarian reserve: a case study of associated adrenal insufficiency

REPRODUCTIVE BIOLOGY AND ENDOCRINOLOGY 2016 APR 26; 14(?):? Article 23
Background: Low testosterone (T), whether due to ovarian and/or adrenal insufficiency, usually results in poor follicle maturation at small growing follicle stages. The consequence is a phenotype of low functional ovarian reserve (LFOR), characterized by poor granulosa cell mass, low anti-Mullerian hormone and estradiol but rising follicle stimulating hormone. Such hypoandrogenism can be of ovarian and/or adrenal origin. Dehydroepiandrosterone sulfate (DHEAS) is exclusively produced by adrenals and, therefore, reflects adrenal androgen production in the zona reticularis. We here determined in a case study of infertile women with LFOR the presence of adrenal hypoandrogenism, its effects on ovarian function, and the possibility of presence of concomitant adrenal insufficiency (AI), thus reflecting insufficiency of all three adrenal cortical zonae. Methods: We searched our center's anonymized electronic research database for women with LFOR, who were also characterized by peripheral adrenal hypoandrogenemia (total testosterone < 16.9 ng/dL) and low DHEAS (< 76.0 mu g/dL). Among 225 women with LFOR, we identified 29 (12.9 %). The adrenal function of so identified women were further investigated with morning cortisol and ACTH levels and/or standard ACTH stimulation tests. We also determined the prevalence of classical AI (insufficiency glucocorticoid production by zona fasciculata) in hypoandrogenic women with LFOR, and impact of adrenal hypoandrogenism on ovaries. Results: Among 14/28 women with adrenal hypoandrogenism due to insufficiency of the zona reticularis available for follow up, 4 (28.6 %) also demonstrated previously unrecognized classical primary, secondary or tertiary AI due to insufficiency of the zona fasciculata. An additional patient with presenting diagnosis of seemingly primary ovarian insufficiency (POI), demonstrated extremely low T and DHEAS levels, a diagnosis of Addison's disease, and was on glucocorticoid but not androgen supplementation. As her dramatic improvement in ovarian function criteria after androgen supplementation confirmed, her correct diagnosis, therefore, was actually secondary ovarian insufficiency (SOI) due to adrenal hypoandrogenism. Conclusions: Women with LFOR, characterized by low T and DHEAS, are also at risk for AI, while women with AI may be at risk for adrenal induced hypoandrogenism and, therefore, SOI. A currently undetermined percentage of POI patients actually are, likely, affected by SOI, a for prognostic reasons highly significant difference in diagnosis.
Rannversson H, Andersen J, Sorensen L, Bang-Andersen B, Park M, Huber T, Sakmar TP, Stromgaard K
Show All Authors

Genetically encoded photocrosslinkers locate the high-affinity binding site of antidepressant drugs in the human serotonin transporter

NATURE COMMUNICATIONS 2016 APR; 7(?):? Article 11261
Despite the well-established role of the human serotonin transporter (hSERT) in the treatment of depression, the molecular details of antidepressant drug binding are still not fully understood. Here we utilize amber codon suppression in a membrane-bound transporter protein to encode photocrosslinking unnatural amino acids (UAAs) into 75 different positions in hSERT. UAAs are incorporated with high specificity, and functionally active transporters have similar transport properties and pharmacological profiles compared with wild-type transporters. We employ ultraviolet-induced crosslinking with p-azido-L-phenylalanine (azF) at selected positions in hSERT to map the binding site of imipramine, a prototypical tricyclic antidepressant, and vortioxetine, a novel multimodal antidepressant. We find that the two antidepressants crosslink with azF incorporated at different positions within the central substrate-binding site of hSERT, while no crosslinking is observed at the vestibular-binding site. Taken together, our data provide direct evidence for defining the high-affinity antidepressant binding site in hSERT.