Stem cell labeling using polyethylenimine conjugated (alpha-NaYbF4:Tm3+)/CaF2 upconversion nanoparticles

We report on a polyethylenimine (PEI) covalently conjugated (alpha-NaYbF4:Tm3+)/CaF2 upconversion nanoparticle (PEI-UCNP) and its use for labeling rat mesenchymal stem cells (rMSCs). The PEI-UCNPs absorb and emit near-infrared light, allowing for improved in vivo imaging depth over conventional probes. We found that such covalent surface conjugation by PEI results in a much more stable PEI-UCNP suspension in PBS compared to conventional electrostatic layer by layer (LbL) self-assembling coating approach. We systematically examined the effects of nanoparticle dose and exposure time on rat mesenchymal stem cell (rMSC) cytotoxicity. The exocytosis of PEI-UCNPs from labeled rMSCs and the impact of PEI-UCNP uptake on rMSC differentiation was also investigated. Our data show that incubation of 100-microg/mL PEI-UCNPs with rMSCs for 4 h led to efficient labeling of the MSCs, and such a level of PEI-UCNP exposure imposed little cytotoxicity to rMSCs (95% viability). However, extended incubation of PEI-UCNPs at the 100 microg/mL dose for 24 hour resulted in some cytotoxicity to rMSCs (60% viability). PEI-UCNP labeled rMSCs also exhibited normal early proliferation, and the internalized PEI-UCNPs did not leak out to cause unintended labeling of adjacent cells during a 14-day transwell culture experiment. Finally, PEI-UCNP labeled rMSCs were able to undergo osteogenic and adipogenic differentiation upon in vitro induction, although the osteogenesis of labeled rMSCs appeared to be less potent than that of the unlabeled rMSCs. Taken together, PEI-UCNPs are promising agents for stem cell labeling and tracking

Photosynthetic and physiological responses of 9 camellia cultivars to high temperature stress and comprehensive evaluation of heat tolerance

Abstract [Objective] The heat tolerance of Camellia attracts more attention due to its rich flower types and colors and long flowering period. Suitable evaluation methods and indexes can provide bases for the heat-tolerance identification, the discovery of heat-tolerance germplasm, and the breeding of new cultivars of Camellia. [Methods] C. uraku and ‘Wirlinga Cascade’ were used as reference materials, and 7 new cultivars of cluster-flowering camellia were selected as test materials. They were cut in vase. After shortterm (5 h) or long-term (7 d) high-temperature (42 ℃/35 ℃) treatment, changes of morphological and photosynthetic indexes were investigated and heat tolerance was evaluated comprehensively. [Results] (1) The contents of chlorophyll, carotenoid, and chlorophyll a/b, net photosynthetic rate (Pn), and stomatal conductance (Gs) of ‘Chuizhi Fenyu’ and ‘Wirlinga Cascade’ were increased. Their maximum photochemical efficiency of PSⅡ (Fv/Fm ), potential activity of PSⅡ (Fv/Fo), and electron transport rate (ETR) were remained at a high level. Additionally, they did not show signs of heat damage after 7 days of high temperatures. Pn and Gs of ‘Jinye Fenyu’, ‘Shangzhi Huazhang’, and ‘Meigui Chun’ were decreased significantly under high temperature stress, while intercellular CO2 concentration (Ci) was increased. Among them, the Fv/Fm, Fv/Fo, and ETR of ‘Jinye Fenyu’ and ‘Shangzhi Huazhang’ were significantly reduced. After 7 days of long-term high temperature stress, these 3 cultivars showed severe heat damage or became dead. (2) 15 individual indicators were converted into 4 independent comprehensive indicators with cumulative contribution rate of 90% through principal component analysis. The comprehensive weight values of chlorophyll content, carotenoid content, and xanthophyll content were higher at 5 h under high temperature stress, and the comprehensive weight values of chlorophyll a/b, Fv/Fm, photochemical quenching coefficient (qP), and non-photochemical quenching coefficient (qN) were higher at 7 d under high temperature stress. [Conclusion] According to the comprehensive evaluation value D , ‘Chuizhi Fenyu’ is a heat-tolerance cultivar, ‘Shangzhi Yueguangqu’, ‘Shangzhi Huanlesong’, and ‘Sweet Gem’ are moderate tolerance, and ‘Meigui Chun’, ‘Shangzhi Huazhang’, and ‘Jinye Fenyu’ are the weakest among the new cultivars of cluster-flowering camellia. Chlorophyll, carotenoid, and xanthophyll contents can be used as the key indicators to analyze the short-term high temperature stress, while chlorophyll a/b, Fv/Fm, qP, and qN can be used as the key indicators to analyze the long-term high temperature stress of Camellia

Therapeutic efficacy of optimal pulse technology in the treatment of chalazions

IntroductionTo evaluate the efficacy of optimized pulse technology in treating chalazia.MethodsProspective before-after study. All patients received two sessions of optimal pulse technology (OPT) with an interval of 1 week. The first visit was before treatment and the patients underwent 2 treatment sessions with a 1-week interval. The non-invasive tear breakup time (NIBUT), corneal fluorescein staining (CFS) score, Schirmer’s test I without anesthesia, conjunctival hyperemia, and meibomian gland area were compared before and after treatment, and the related factors of curative effect were analyzed.Results23 patients (23 eyes) with chalazia were included. All patients received two sessions of OPT treatment at 1-week intervals. Following the first OPT treatment, a reduction in the chalazion size was observed in 17 patients (73.91%). One patient was completely cured, and 1 patient had an increase in the diameter of the chalazion. The meibomian gland area increased significantly compared to before treatment (p = 0.023). Compared with baseline, the conjunctival congestion and ST decreased, NIBUT increased, and there was no statistical difference. After the second treatment, the chalazion size decreased in 21 cases, and 3 patients were cured. A significant increase in the meibomian gland area compared with the baseline area (p < 0.001). Additionally, conjunctival congestion decreased significantly. After two sessions, the Schirmer test exhibited a decrease, and NIBUT increased, although these changes did not reach statistical significance. The curative effect was unrelated to sex, age, first onset, single disease, and other factors.ConclusionAfter treatment, the diameter of chalazions was reduced in 91.3% of the patients, and the area of the meibomian gland was significantly increased compared with that before treatment, which suggested that 2 OPT treatments at an interval of 1 week can improve the signs of adult patients in the non-acute infectious stage with chalazia

JUN dependency in distinct early and late BRAF inhibition adaptation states of melanoma.

A prominent mechanism of acquired resistance to BRAF inhibitors in BRAF (V600) -mutant melanoma is associated with the upregulation of receptor tyrosine kinases. Evidences suggested that this resistance mechanism is part of a more complex cellular adaptation process. Using an integrative strategy, we found this mechanism to invoke extensive transcriptomic, (phospho-) proteomic and phenotypic alterations that accompany a cellular transition to a de-differentiated, mesenchymal and invasive state. Even short-term BRAF-inhibitor exposure leads to an early adaptive, differentiation state change-characterized by a slow-cycling, persistent state. The early persistent state is distinct from the late proliferative, resistant state. However, both differentiation states share common signaling alterations including JUN upregulation. Motivated by the similarities, we found that co-targeting of BRAF and JUN is synergistic in killing fully resistant cells; and when used up-front, co-targeting substantially impairs the formation of the persistent subpopulation. We confirmed that JUN upregulation is a common response to BRAF inhibitor treatment in clinically treated patient tumors. Our findings demonstrate that events shared between early- and late-adaptation states provide candidate up-front co-treatment targets

Advanced Glycation End Products-Induced Activation of Keratinocytes: A Mechanism Underlying Cutaneous Immune Response in Psoriasis

Psoriasis is a common inflammatory skin disease, in which epidermal keratinocytes play a vital role in its pathogenesis by acting both as the responder and as the accelerator to the cutaneous psoriatic immune response. Advanced glycation end products (AGEs) are a class of proinflammatory metabolites that are commonly accumulating in cardiometabolic disorders. Recent studies have also observed the increased level of AGEs in the serum and skin of psoriasis patients, but the role of AGEs in psoriatic inflammation has not been well investigated. In the present study, we initially detected abnormal accumulation of AGEs in epidermal keratinocytes of psoriatic lesions collected from psoriasis patients. Furthermore, AGEs promoted the proliferation of keratinocytes via upregulated Keratin 17 (K17)-mediated p27KIP1 inhibition followed by accelerated cell cycle progression. More importantly, AGEs facilitated the production of interleukin-36 alpha (IL-36α) in keratinocytes, which could enhance T helper 17 (Th17) immune response. In addition, the induction of both K17 and IL-36α by AGEs in keratinocytes was dependent on the activation of signal transducer and activator of transcription 1/3 (STAT1/3) signaling pathways. At last, the effects of AGEs on keratinocytes were mediated by the receptor for AGEs (RAGE). Taken together, these findings support that AGEs potentiate the innate immune function of keratinocytes, which contributes to the formation of psoriatic inflammation. Our study implicates AGEs as a potential pathogenic link between psoriasis and cardiometabolic comorbidities

Association between ABO genotypes and risk of dementia and neuroimaging markers: roles of sex and APOE status

BackgroundWhether the relationships between ABO blood genotypes (AA, AO, BB, BO, AB, and OO) and dementia are modified by gender and APOE status has been unclear.MethodsWe used data from the UK Biobank, a population-based cohort study of 487,425 individuals. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CI) between ABO genotypes and risk of dementia. Multivariable linear regression models were used to estimate the relationship between ABO genotypes and MRI-based brain indices.ResultsOverall, 487,425 participants were included at baseline. After 34 million person-years follow up, 7,548 patients developed all-cause dementia. Before stratifying by sex and APOE status, compared to OO genotype, BB genotype was associated with increased risk of all-cause dementia (1.36, 1.03–1.80) and other types dementia (1.65, 1.20–2.28). After stratifying by sex, only in males, BB genotype was associated with higher risk of all-cause dementia (1.44, 1.02–2.09) and other types of dementia (1.95, 1.30–2.93). AB genotype in males was also associated with increased AD (1.34, 1.04–1.72). After further stratifying by APOE e4 status, BB genotype with two APOE e4 alleles showed even stronger association with all-cause dementia 4.29 (1.57, 11.72) and other types dementia (5.49, 1.70–17.69) in males. Also in males, AA genotype with one APOE e4 was associated with increased risks of all-cause dementia (1.27, 1.04–1.55), AD (1.45, 1.09–1.94) and other types dementia (1.40, 1.08–1.81). Linear regression models showed that in both sexes with APOE e4, AA genotype was associated with reduced total grey matter volume.ConclusionSex and APOE e4 carrier status modified the association between ABO genotypes and risk of dementia. In males, BB genotype was consistently associated with increased risk of dementia, especially in those with two APOE e4 alleles. Also, in males with one APOE e4, AA genotype might be linked to higher risk of dementia

Genetic Ablation of PLA2G6 in Mice Leads to Cerebellar Atrophy Characterized by Purkinje Cell Loss and Glial Cell Activation

Infantile neuroaxonal dystrophy (INAD) is a progressive, autosomal recessive neurodegenerative disease characterized by axonal dystrophy, abnormal iron deposition and cerebellar atrophy. This disease was recently mapped to PLA2G6, which encodes group VI Ca2+-independent phospholipase A2 (iPLA2 or iPLA2β). Here we show that genetic ablation of PLA2G6 in mice (iPLA2β-/-) leads to the development of cerebellar atrophy by the age of 13 months. Atrophied cerebella exhibited significant loss of Purkinje cells, as well as reactive astrogliosis, the activation of microglial cells, and the pronounced up-regulation of the pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). Moreover, glial cell activation and the elevation in TNF-α and IL-1β expression occurred before apparent cerebellar atrophy. Our findings indicate that the absence of PLA2G6 causes neuroinflammation and Purkinje cell loss and ultimately leads to cerebellar atrophy. Our study suggests that iPLA2β-/- mice are a valuable model for cerebellar atrophy in INAD and that early anti-inflammatory therapy may help slow the progression of cerebellar atrophy in this deadly neurodegenerative disease

Regional glutamine deficiency in tumours promotes dedifferentiation through inhibition of histone demethylation

Poorly organized tumour vasculature often results in areas of limited nutrient supply and hypoxia. Despite our understanding of solid tumour responses to hypoxia, how nutrient deprivation regionally affects tumour growth and therapeutic response is poorly understood. Here, we show that the core region of solid tumours displayed glutamine deficiency compared with other amino acids. Low glutamine in tumour core regions led to dramatic histone hypermethylation due to decreased α-ketoglutarate levels, a key cofactor for the Jumonji-domain-containing histone demethylases. Using patient-derived ^(V600E)BRAF melanoma cells, we found that low-glutamine-induced histone hypermethylation resulted in cancer cell dedifferentiation and resistance to BRAF inhibitor treatment, which was largely mediated by methylation on H3K27, as knockdown of the H3K27-specific demethylase KDM6B and the methyltransferase EZH2 respectively reproduced and attenuated the low-glutamine effects in vitro and in vivo. Thus, intratumoral regional variation in the nutritional microenvironment contributes to tumour heterogeneity and therapeutic response

Regional glutamine deficiency in tumours promotes dedifferentiation through inhibition of histone demethylation

Poorly organized tumour vasculature often results in areas of limited nutrient supply and hypoxia. Despite our understanding of solid tumour responses to hypoxia, how nutrient deprivation regionally affects tumour growth and therapeutic response is poorly understood. Here, we show that the core region of solid tumours displayed glutamine deficiency compared with other amino acids. Low glutamine in tumour core regions led to dramatic histone hypermethylation due to decreased α-ketoglutarate levels, a key cofactor for the Jumonji-domain-containing histone demethylases. Using patient-derived ^(V600E)BRAF melanoma cells, we found that low-glutamine-induced histone hypermethylation resulted in cancer cell dedifferentiation and resistance to BRAF inhibitor treatment, which was largely mediated by methylation on H3K27, as knockdown of the H3K27-specific demethylase KDM6B and the methyltransferase EZH2 respectively reproduced and attenuated the low-glutamine effects in vitro and in vivo. Thus, intratumoral regional variation in the nutritional microenvironment contributes to tumour heterogeneity and therapeutic response