Basal Accumulation Research Articles

Molecular mechanisms underlying natural deficient and ultraviolet-induced accumulation of anthocyanin in the peel of 'Jinxiu' peach.

Peach varieties that differ in red coloration due to varied anthocyanin accumulation result from transcriptional regulation by PpMYB10s, a group of specific R2R3 MYBs. Here we investigated the mechanisms driving a lack of anthocyanin in yellow-skinned 'Jinxiu' peach peel, as well as accumulation induced by UV irradiance. It was found that PpMYB10.1, PpMYB10.2 and PpMYB10.3 were positive regulators of anthocyanin accumulation, but the stimulation by PpMYB10.2 was weak. Low expression of PpMYB10.1 causes natural anthocyanin deficiency in 'Jinxiu' peel. However, the promoter sequences of PpMYB10.1 were identical in 'Jinxiu' and a naturally red-coloured peach 'Hujingmilu'. Therefore, potential negative regulator(s) upstream of PpMYB10.1 were explored. A novel R2R3-MYB repressor termed PpMYB80 was identified through comparative transcriptomic analysis and then functionally confirmed via transiently overexpressing and silencing in peach fruit, as well as transformation in tobacco. PpMYB80 directly binds to the promoter of PpMYB10.1 and inhibits its expression, but does not affect PpMYB10.3. In UV-exposed 'Jinxiu' fruit, expression of PpMYB10.3 was upregulated, while PpMYB10.1 remained low and PpMYB80 enhanced, which results in accumulation of anthocyanin in peel. This study revealed a transcriptional cascade involving PpMYB activators and repressors in regulating basal and UV-induced anthocyanin accumulation in peach peel.

D-Mannose reduces cellular senescence and NLRP3/GasderminD/IL-1β-driven pyroptotic uroepithelial cell shedding in the murine bladder

Aging is a risk factor for disease via increased susceptibility to infection, decreased ability to maintain homeostasis, inefficiency in combating stress, and decreased regenerative capacity. Multiple diseases, including urinary tract infection (UTI), are more prevalent with age; however, the mechanisms underlying the impact of aging on the urinary tract mucosa and the correlation between aging and disease remain poorly understood. Here, we show that, relative to young (8-12weeks) mice, the urothelium of aged (18-24months) female mice accumulates large lysosomes with reduced acid phosphatase activity and decreased overall autophagic flux in the aged urothelium, indicative of compromised cellular homeostasis. Aged bladders also exhibit basal accumulation of reactive oxygen species (ROS) and a dampened redox response, implying heightened oxidative stress. Furthermore, we identify a canonical senescence-associated secretory phenotype (SASP) in the aged urothelium, along with continuous NLRP3-inflammasome- and Gasdermin-D-dependent pyroptotic cell death. Consequently, aged mice chronically exfoliate urothelial cells, further exacerbating age-related urothelial dysfunction. Upon infection with uropathogenic E.coli, aged mice harbor increased bacterial reservoirs and are more prone to spontaneous recurrent UTI. Finally, we discover that treatment with D-mannose, a natural bioactive monosaccharide, rescues autophagy flux, reverses the SASP, and mitigates ROS and NLRP3/Gasdermin/interleukin (IL)-1β-driven pyroptotic epithelial cell shedding in aged mice. Collectively, our results demonstrate that normal aging affects bladder physiology, with aging alone increasing baseline cellular stress and susceptibility to infection, and suggest that mannose supplementation could serve as a senotherapeutic to counter age-associated urothelial dysfunction.

The nuclear entry of the aryl hydrocarbon receptor (AHR) relies on the first nuclear localization signal and can be negatively regulated through IMPα/β specific inhibitors

The human aryl hydrocarbon receptor (AHR) undergoes continuous shuttling between nucleus and cytoplasm. Binding to exogenous or endogenous ligands promotes its rapid nuclear import. The proposed mechanism for the ligand-dependent import is based on exposing the bipartite nuclear localisation signal (NLS) to members of the importin (IMP) superfamily. Among this, the molecular interactions involved in the basal import still need to be clarified. Utilizing fluorescently fused AHR variants, we recapitulated and characterized AHR localization and nucleo-cytoplasmic shuttling in living cells. Analysis of AHR variants carrying NLS point mutations demonstrated a mandatory role of first (13RKRRK17) and second (37KR-R40) NLS segments on the basal import of AHR. Further experiments indicated that ligand-induced import is mainly regulated through the first NLS, while the second NLS is supportive but not essential. Additionally, applying IMPα/β specific inhibitors, ivermectin (IVM) and importazole (IPZ), slowed down the ligand-induced import and, correspondingly, decreased the basal nuclear accumulation of the receptor. In conclusion, our data show that ligand-induced and basal nuclear entry of AHR rely on the same mechanism but are controlled uniquely by the two NLS components.

Restoration of low-intensity fire in Quercus-Pinus mixedwoods following a prolonged period of fire exclusion

Low-intensity surface fire is required to restore and maintain Quercus-Pinus mixedwood composition, structure, and function. However, historical fire exclusion has resulted in altered vegetation-fuel-fire feedbacks in long-unburned mixedwoods. Fire is now being reintroduced to reduce fire-intolerant understory and midstory stem density, consume excessive litter accumulation, eradicate the duff layer, and achieve various other goals; however, the consequences of restoring fire are poorly understood. The goal of this study was to quantify the effects of fire reintroduction on intra-stand Pinus echinata neighborhoods in a mixed Quercus-P. echinata stand following an extended period of fire exclusion. We report results from a 3-year sampling of the effects of one dormant season and one early growing season fire on woody plant dynamics, understory light, fuel conditions, and P. echinata basal duff-ring accumulation. The sapling assemblage was unaffected by one fire, but the second fire resulted in shoot mortality across all taxa. Understory light availability was unchanged after two fires, and litter depth was significantly reduced after the first and second fire. We found that fire seasonality was likely more important than fuel conditions to achieve desired fire effects. Our results indicated that continued fire and midstory treatment will be required to regenerate P. echinata.

Nrl:CreERT2 mouse model to induce mosaic gene expression in rod photoreceptors.

Photoreceptors are sensory neurons that capture light within their outer segment, a narrow cylindrical organelle stacked with disc-shaped membranes housing the visual pigment. Photoreceptors are the most abundant neurons in the retina and are tightly packed to maximize the capture of incoming light. As a result, it is challenging to visualize an individual cell within a crowded photoreceptor population. To address this limitation, we developed a rod-specific mouse model that expresses tamoxifen-inducible cre recombinase under the control of the Nrl promoter. We characterized this mouse using a farnyslated GFP (GFPf) reporter mouse and found mosaic rod expression throughout the retina. The number of GFPf-expressing rods stabilized within 3 days post tamoxifen injection. At that time, the GFPf reporter began to accumulate in basal disc membranes. Using this new reporter mouse, we attempted to quantify the time course of photoreceptor disc renewal in WT and Rd9 mice, a model of X-linked retinitis pigmentosa previously proposed to have a reduced disc renewal rate. We measured GFPf accumulation in individual outer segments at 3 and 6 days post-induction and found that basal accumulation of the GFPf reporter was unchanged between WT and Rd9 mice. However, rates of renewal based on the GFPf measurements were inconsistent with historical calculations from radiolabeled pulse-chase experiments. By extending GFPf reporter accumulation to 10 and 13 days we found that this reporter had an unexpected distribution pattern that preferentially labeled the basal region of the outer segment. For these reasons the GFPf reporter cannot be used for measuring rates of disc renewal. Therefore, we used an alternative method that labels newly forming discs with a fluorescent dye to measure disc renewal rates directly in the Rd9 model and found it was not significantly different from WT. Our study finds that the Rd9 mouse has normal rates of disc renewal and introduces a novel Nrl:CreERT2 mouse for gene manipulation of individual rods.

Quantification of basal stem cell elongation and stress fiber accumulation in the pseudostratified airway epithelium during the unjamming transition.

Under homeostatic conditions, epithelial cells remain non-migratory. However, during embryonic development and pathological conditions, they become migratory. The mechanism underlying the transition of the epithelial layer between non-migratory and migratory phases is a fundamental question in biology. Using well-differentiated primary human bronchial epithelial cells that form a pseudostratified epithelium, we have previously identified that a confluent epithelial layer can transition from a non-migratory to migratory phase through an unjamming transition (UJT). We previously defined collective cellular migration and apical cell elongation as hallmarks of UJT. However, other cell-type-specific changes have not been previously studied in the pseudostratified airway epithelium, which consists of multiple cell types. Here, we focused on the quantifying morphological changes in basal stem cells during the UJT. Our data demonstrate that during the UJT, airway basal stem cells elongated and enlarged, and their stress fibers elongated and aligned. These morphological changes observed in basal stem cells correlated to the previously defined hallmarks of the UJT. Moreover, basal cell and stress fiber elongation were observed prior to apical cell elongation. Together, these morphological changes indicate that basal stem cells in pseudostratified airway epithelium are actively remodeling, presumably through accumulation of stress fibers during the UJT.

Optimizing fertilizer schedules for irrigated chickpea (Cicer arietinum L.) under scarce rainfall zone of Andhra Pradesh

Conventionally chickpea is cultivated as rainfed crop but under irrigated conditions the optimum dose of fertilizers was not known and the research was also limited. The purpose of this study was to study the optimum dose of fertilizers for chickpea under irrigated conditions. A field experiment was conducted to study the growth and yield of chickpea under varied levels of fertilizer application on sandy loam soils at Agricultural College, Mahanandi during rabi 2021-22. The experimental field was laid out in a randomized block design with 10 treatments and replicated thrice. Nitrogen and phosphorus were applied through urea and single super phosphate, respectively, to all the plots. The results revealed that significantly higher and comparable values of plant height (44.0 cm), number of branches/plant (28.7), number of pods/plant (63.4), 100-seed weight (32.4 g), seed yield (1346.1 kg/ha), gross returns (71344.7 Rs./ha), net returns (43187.7 Rs./ha) and B : C ratio (2.5) were registered with treatment 20 kg N basal+20 kg N split+60 kg P2O5 basal (T9) and higher dry matter accumulation (7168.5 kg/ha) and haulm yield (1352.0 kg/ha) with 20 kg N basal+20 kg N split+70 kg P2O5 basal (T10). Number of seeds/pod and harvest index were not significantly affected by levels of fertilizer application.

AIM1-dependent high basal salicylic acid accumulation modulates stomatal aperture in rice.

The basal levels of salicylic acid (SA) vary dramatically among plant species. In the shoot, for example, rice contains almost 100 times higher SA levels than Arabidopsis. Despite its high basal levels, neither the biosynthetic pathway nor the biological functions of SA are well understood in rice. Combining with metabolite analysis, physiological, and genetic approaches, we found that the synthesis of basal SA in rice shoot is dependent on OsAIM1, which encodes a beta-oxidation enzyme in the phenylalanine ammonia-lyase (PAL) pathway. Compromised SA accumulation in the Osaim1 mutant led to a lower shoot temperature than wild-type plants. However, this shoot temperature defect resulted from increased transpiration due to elevated steady-state stomatal aperture in the mutant. Furthermore, the high basal SA level is required for sustained expression of OsWRKY45 to modulate the steady-state stomatal aperture and shoot temperature in rice. Taken together, these results provide the direct genetic evidence for the critical role of the PAL pathway in the biosynthesis of high basal level SA in rice, which plays an important role in the regulation of steady-state stomatal aperture to promote fitness under stress conditions.

Estimation of bedload sedimentation rate in a paleo-drowned river-valley

Extensive, high-resolution seismic data were correlated with borehole, land use, and geological data to calculate the mass of genetically different sediment deposits in the Middle Harbour estuary in Sydney, Australia. Middle Harbour is a drowned-river valley located adjacent to the larger Sydney estuary. The estuary follows a well-defined sedimentation model featuring small fluvial bedload delta deposits in the upper reaches of the embayments, a deep, central extensive mud basin overlying transgressive basal accumulations and a large flood-tide delta at the entrance. Deposits of an estimated 5094 t of bedload, 21,143 t of suspended sediment and 5947 t of transgressive basal material located in the estuary provided average sediment accumulation rates of 0.68 t year−1, 1.29 t year−1, and 2.86 t year−1, respectively. These rates, determined from measured accumulations, were surprisingly low and substantially smaller than modelled rates. However, low sediment accumulation rates for suspended material may be due to fine sediment escaping over the top of the marine tidal delta, which effectively traps all bedload material from exiting the Harbour. Results of this study indicate that Holocene bedload sedimentation in Middle Harbour was slow and regular until a rapid increase after urbanisation commenced in the catchment. Most pre-Holocene material was eroded from Middle Harbour during the Last Glacial period with sediment currently present in the estuary having been deposited since sea-level recovery.

Lysosome Inhibition Reduces Basal and Nutrient-Induced Fat Accumulation in Caenorhabditis elegans.

A long-term energy nutritional imbalance fundamentally causes the development of obesity and associated fat accumulation. Lysosomes, as nutrient-sensing and lipophagy centers, critically control cellular lipid catabolism in response to nutrient deprivation. However, whether lysosome activity is directly involved in nutrient-induced fat accumulation remains unclear. In this study, worm fat accumulation was induced by 1 mM glucose or 0.02 mM palmitic acid supplementation. Along with the elevation of fat accumulation, lysosomal number and acidification were also increased, suggesting that lysosome activity might be correlated with nutrient-induced fat deposition in Caenorhabditis elegans. Furthermore, treatments with the lysosomal inhibitors chloroquine and leupeptin significantly reduced basal and nutrient-induced fat accumulation in C. elegans. The knockdown of hlh-30, which is a critical gene in lysosomal biogenesis, also resulted in worm fat loss. Finally, the mutation of aak-2, daf-15, and rsks-1 showed that mTORC1 (mechanistic target of rapamycin complex-1) signaling mediated the effects of lysosomes on basal and nutrient-induced fat accumulation in C. elegans. Overall, this study reveals the previously undescribed role of lysosomes in overnutrition sensing, suggesting a new strategy for controlling body fat accumulation.

A Secretory Vesicle Failure in Parkinson's Disease Occurs in Human Platelets.

ObjectiveThe presence of elevated dopamine (DA) and its major metabolites in the cytosol of neurons has been associated with their vulnerability in Parkinson's disease (PD). Over 99% of the cell's amines are confined to secretory vesicles (SVs), making these structures fundamental in the regulation of cytosolic DA levels. SVs of platelets use similar, if not the same mechanisms to accumulate serotonin in SVs as dopaminergic neurons do to store DA. Hence, any functional defects in platelets probably mirrors events in DA neurons.MethodsWe have isolated fresh platelets from the blood of 75 PD patients, 116 matched controls and 24 patients with Parkinsonism, assaying serotonin handling (basal content, accumulation, secretion and spontaneous leakage).ResultsWe found a dramatic decrease in the serotonin content and uptake by SVs, as well as decreased thrombin‐induced release by platelets from PD patients but not in those from most Parkinsonism cases. Platelets from PD patients also failed to retain serotonin in SVs.InterpretationThese findings indicate a functional impairment in the handling of amines by SVs in PD patients. This defect may serve as a biomarker of PD, and the approach described here may be potentially used for the subclinical detection of PD and to establish a platform to assay disease modifying drugs. ANN NEUROL 2022

Canine osteosarcoma cells exhibit basal accumulation of multiple chaperone proteins and are sensitive to small molecule inhibitors of GRP78 and heat shock protein function.

Osteosarcoma is the most common type of bone cancer in dogs and humans, with significant numbers of patients experiencing treatment failure and disease progression. In our search for new approaches to treat osteosarcoma, we previously detected multiple chaperone proteins in the surface-exposed proteome of canine osteosarcoma cells. In the present study, we characterized expression of representative chaperones and find evidence for stress adaptation in canine osteosarcoma cells relative to osteogenic progenitors from normal bone. We compared the cytotoxic potential of direct (HA15) and putative (OSU-03012) inhibitors of Grp78 function and found canine POS and HMPOS osteosarcoma cells to be more sensitive to both compounds than normal cells. HA15 and OSU-03012 increased the thermal stability of Grp78 in intact POS cells at low micromolar concentrations, but each induced distinct patterns in Grp78 expression without significant change in Grp94. Both inhibitors were as effective alone as carboplatin and showed little evidence of synergy in combination treatment. However, HMPOS cells with acquired resistance to carboplatin were sensitive to inhibition of Grp78 (by HA15; OSU-03012), Hsp70 (by VER-155008), and Hsp90 (by 17-AAG) function. These results suggest that multiple nodes within the osteosarcoma chaperome may be relevant chemotherapeutic targets against platinum resistance.

Not all trees can make a forest: Tree species composition and competition control forest encroachment in a tropical savanna

Abstract Forest encroachment into savannas is a widespread phenomenon, the rate of which may depend on soil conditions, species composition or changes in stand structure. As savanna specialist trees are replaced by generalist species, rates of stand development may increase. Because generalists can persist in forests, they are likely to grow more quickly and survive longer in dense stands, compared to savanna specialists. Furthermore, the faster growth rates of generalists may allow them to overtop and outcompete savanna specialists, causing rapid species turnover. We measured growth and survival of 6,147 individuals of 112 species of savanna and generalist tree species over a period of 10 years in an ecological reserve in Assis, São Paulo State, Brazil. We modelled growth and mortality as a function of soil texture and nutrients, tree size, competitive neighbourhood, and membership in savanna or generalist (species which can persist in forests and savannas) functional groups. Tree growth and survival was strongly influenced by competition, as estimated by the basal area of trees taller than a focal tree. At the stand level, savanna species are unable to contribute basal area growth in closed stands, while generalist species continue to increase in basal area even at high stand basal area. This phenomenon is driven by differences in growth and mortality. Generalists grew faster than savanna species, both in height and diameter. This difference in growth rates led to savanna species becoming suppressed more rapidly than generalists. When suppressed, savanna species were more than twice as likely to die than were generalists. Soils had inconsistent and mostly weak effects which were difficult to separate from gradients of stand structure. Synthesis. We demonstrate that the presence of generalist trees accelerates the rates of basal area accumulation due to their greater growth rates and tolerance of shading. Generalists outcompete savanna trees by growing faster in the open and overtopping savanna specialists. Due to the slow growth and high mortality of savanna species in the shade, they are unable to form closed‐canopy stands. Accounting for differences among functional types and development of vegetation structure is critical for modelling forest encroachment.

Functional characterization of naturally-occurring constitutively activating/inactivating mutations in equine follicle-stimulating hormone receptor.

ObjectiveFollicle-stimulating hormone (FSH) is the central hormone involved in mammalian reproduction, maturation at puberty, and gamete production that mediates its function by control of follicle growth and function. The present study investigated the mutations involved in the regulation of FSH receptor (FSHR) activation.MethodsWe analyzed seven naturally-occurring mutations that were previously reported in human FSHR (hFSHR), in the context of equine FSHR (eFSHR); these include one constitutively activation variant, one allelic variant, and five inactivating variants. These mutations were introduced into wild-type eFSHR (eFSHR-wt) sequence to generate mutants that were designated as eFSHR-D566G, -A306T, -A189V, -N191I, -R572C, -A574V, and -R633H. Mutants were transfected into PathHunter EA-parental CHO-K1 cells expressing β-arrestin. The biological function of mutants was analyzed by quantitating cAMP accumulation in cells incubated with increasing concentrations of FSH.ResultsCells expressing eFSHR-D566G exhibited an 8.6-fold increase in basal cAMP response, as compared to that in eFSHR-wt. The allelic variation mutant eFSHR-A306T was not found to affect the basal cAMP response or half maximal effective concentration (EC50) levels. On the other hand, eFSHR-D566G and eFSHR-A306T displayed a 1.5- and 1.4-fold increase in the maximal response, respectively. Signal transduction was found to be completely impaired in case of the inactivating mutants eFSHR-A189V, -R572C, and -A574V. When compared with eFSHR-wt, eFSHR-N191I displayed a 5.4-fold decrease in the EC50 levels (3,910 ng/mL) and a 2.3-fold decrease in the maximal response. In contrast, cells expressing eFSHR-R633H displayed in a similar manner to that of the cells expressing the eFSHR-wt on signal transduction and maximal response.ConclusionThe activating mutant eFSHR-D566G greatly enhanced the signal transduction in response to FSH, in the absence of agonist treatment. We suggest that the state of activation of the eFSHR can modulate its basal cAMP accumulation.

Bed topography and marine ice-sheet stability

AbstractThis paper examines the effect of basal topography and strength on the grounding-line position, flux and stability of rapidly-sliding ice streams. It does so by supposing that the buoyancy of the ice stream is small, and of the same order as the longitudinal stress gradient. Making this scaling assumption makes the role of the basal gradient and accumulation rate explicit in the lowest order expression for the ice flux at the grounding line and also provides the transcendental equation for the grounding-line position. It also introduces into the stability condition terms in the basal curvature and accumulation-rate gradient. These expressions revert to well-established expressions in circumstances in which the thickness gradient is large at the grounding line, a result which is shown to be the consequence of the non-linearity of the flow. The behaviour of the grounding-line flux is illustrated for a range of bed topographies and strengths. We show that, when bed topography at a horizontal scale of several tens of ice thicknesses is present, the grounding-line flux and stability have more complex dependencies on bed gradient than that associated with the ‘marine ice-sheet instability hypothesis’, and that unstable grounding-line positions can occur on prograde beds as well as stable positions on retrograde beds.

The hydrology of glacier‐bed overdeepenings: Sediment transport mechanics, drainage system morphology, and geomorphological implications

AbstractEvacuation of basal sediment by subglacial drainage is an important mediator of rates of glacial erosion and glacier flow. Glacial erosion patterns can produce closed basins (i.e., overdeepenings) in glacier beds, thereby introducing adverse bed gradients that are hypothesized to reduce drainage system efficiency and thus favour basal sediment accumulation. To establish how the presence of a terminal overdeepening might mediate seasonal drainage system evolution and glacial sediment export, we measured suspended sediment transport from Findelengletscher, Switzerland during late August and early September 2016. Analyses of these data demonstrate poor hydraulic efficiency of drainage pathways in the terminus region but high sediment availability. Specifically, the rate of increase of sediment concentration with discharge was found to be significantly lower than that anticipated if channelized flow paths were present. Sediment availability to these flow paths was also higher than would be anticipated for discrete bedrock‐floored subglacial channels. Our findings indicate that subglacial drainage in the terminal region of Findelengletscher is dominated by distributed flow where entrainment capacity increases only marginally with discharge, but flow has extensive access to an abundant sediment store. This high availability maintains sediment connectivity between the glacial and proglacial realm and means daily sediment yield is unusually high relative to yields exhibited by similar Alpine glaciers. We present a conceptual model illustrating the potential influence of ice‐bed morphology on subglacial drainage evolution and sediment evacuation mechanics, patterns and yields, and recommend that bed morphology should be an explicit consideration when monitoring and evaluating glaciated basin sediment export rates.

CEP164 is essential for efferent duct multiciliogenesis and male fertility.

Cilia are evolutionarily conserved microtubule-based structures that perform diverse biological functions. Cilia are assembled on basal bodies and anchored to the plasma membrane via distal appendages. In the male reproductive tract, multicilia in efferent ducts (EDs) move in a whip-like motion to prevent sperm agglutination. Previously, we demonstrated that the distal appendage protein CEP164 recruits Chibby1 (Cby1) to basal bodies to facilitate basal body docking and ciliogenesis. Mice lacking CEP164 in multiciliated cells (MCCs) (FoxJ1-Cre;CEP164fl/fl) show a significant loss of multicilia in the trachea, oviduct, and ependyma. In addition, we observed male sterility; however, the precise role of CEP164 in male fertility remained unknown. Here, we report that the seminiferous tubules and rete testis of FoxJ1-Cre;CEP164fl/fl mice exhibit substantial dilation, indicative of dysfunctional multicilia in the EDs. We found that multicilia were hardly detectable in the EDs of FoxJ1-Cre;CEP164fl/fl mice although FoxJ1-positive immature cells were present. Sperm aggregation and agglutination were commonly noticeable in the lumen of the seminiferous tubules and EDs of FoxJ1-Cre;CEP164fl/fl mice. In FoxJ1-Cre;CEP164fl/fl mice, the apical localization of Cby1 and the transition zone marker NPHP1 was severely diminished, suggesting basal body docking defects. TEM analysis of EDs further confirmed basal body accumulation in the cytoplasm of MCCs. Collectively, we conclude that male infertility in FoxJ1-Cre;CEP164fl/fl mice is caused by sperm agglutination and obstruction of EDs due to loss of multicilia. Our study, therefore, unravels an essential role of the distal appendage protein CEP164 in male fertility.

HsfA1d promotes hypocotyl elongation under chilling via enhancing expression of ribosomal protein genes in Arabidopsis

How plants maintain growth under non-freezing low temperatures (chilling) is not well understood. Here we use hypocotyl elongation under dark to investigate molecular mechanisms for chilling growth in Arabidopsis thaliana. The function of HsfA1d (Heat shock transcription factor A1d) in chilling growth is investigated by physiological and molecular characterization of its mutants. Subcellular localization of HsfA1d under chilling is analyzed. Potential target genes of HsfA1d were identified by transcriptome analysis, chromatin immunoprecipitation, transcriptional activation assay, and mutant characterization. HsfA1d is a positive regulator of hypocotyl elongation under chilling. It promotes expression of a large number of ribosome biogenesis genes to a moderate but significant extent under chilling. HsfA1d could bind to the promoter regions of two ribosome protein genes tested and promote their expression. The loss of function of one ribosome gene also reduced hypocotyl elongation under chilling. In addition, HsfA1d did not have increased nuclear accumulation under chilling and its basal nuclear accumulation is promoted by a salicylic acid receptor under chilling. This study thus unveils a new HsfA1d-mediated pathway that promotes the expression of ribosomal protein genes which may maintain overall protein translation for plant growth in chilling.

The possible involvement of granulysin mediated cytotoxicity in keratinocytes disruption in lichen planus

Lichen planus is a chronic mucocutanous disorder histopathologically characterized with a keratinocytes apoptosis, subsequent basal cell layer liquefaction and accumulation of the inflammatory infiltrate in papillary dermis. A formation of apoptotic bodies in basal cell layer is due to a cytotoxic lymphocyte attack to the basal keratinocytes. It has been demonstrated that the cytotoxic molecules included in this attack are perforin and granzyme B. Both molecules are found upregulated in CD8+ lymphocytes that are in close contact to keratinocytes. However, their amount is lower in lichen planus than in other skin disease characterized by liquefaction and vacuolar degeneration of the basal epidermal layer. This could speculate about other cytotoxic molecule such as granulysin that could mediate keratinocyte apoptosis. Therefore, in this article we hypothesize about the crucial role of granulysin molecule in keratinocytes killing that could contribute to a lichen planus pathogenesis.

Novel bone-targeted parathyroid hormone-related peptide antagonists inhibit breast cancer bone metastases

Patients with advanced breast cancer often develop bone metastases. Treatment is limited to palliative care. Parathyroid hormone (PTH)/parathyroid hormone-related peptide (PTHrP) antagonists for bone metastases failed clinically due to short half-life and inadequate concentration in bone. We synthesized two novel PTHrP antagonists fused to an inert bacterial collagen binding domain (CBD) that directs drugs to bone. PTH(7-33)-CBD is an N-terminal truncated PTHrP antagonist. [W2]PTH(1-33)-CBD is an PTHrP inverse-agonist. The aim of this study was to assess PTH(7-33)-CBD to reduce breast cancer bone metastases and prevent osteolytic destruction in mice and to assess both drugs for apoptosis of breast cancer cells in vitro and inhibition of PTH receptor (PTHR1). PTH(7-33)-CBD (1000 µg/kg, subcutaneous) or vehicle was administered 24 h prior to MDA-MB-231 breast cancer cell inoculation into the tibia marrow. Weekly tumor burden and bone density were measured. Pharmacokinetic analysis of PTH(7-33)-CBD in rat serum was evaluated. Drug effect on cAMP accumulation in SaOS-2 osteosarcoma cells and apoptosis of MDA-MB-231 cells was assessed. PTH(7-33)-CBD reduced MDA-MB-231 tumor burden and osteolytic destruction in mice 4-5 weeks post-treatment. PTH(7-33)-CBD (1000 μg/kg i.v. and subcutaneous) in rats was rapidly absorbed with peak concentration 5-min and terminal half-life 3-h. Bioavailability by the subcutaneous route was 43% relative to the i.v. route. PTH(7-33)-CBD was detected only on rat periosteal bone surfaces that stained positive for collagen-1. PTH(7-33)-CBD and [W2]PTH(1-33)-CBD (10-8M) blocked basal and PTH agonist-induced cAMP accumulation in SaOS-2 osteosarcoma cells. Both drugs induced PTHR1-dependent apoptosis of MDA-MB-231 cells in vitro. Novel bone-targeted PTHrP antagonists represent a new paradigm for treatment of breast cancer bone metastases.