Intracellular Factors Research Articles

The role of microRNA in the developmental and functional regulation of NK cells

Natural killer (NK) cells are important innate effector cells serving as the first line of defense against certain infections and tumors. NK cells also play a role in regulating immune responses. NK cells develop from hematopoietic stem cells in the bone marrow. The development, maturation and function of NK cells depend on the regulation of microenvironment, intracellular transcription factors and post-transcriptional regulations. MicroRNA (miRNA) is a group of small non-coding RNAs that regulate the expression of target genes at the post-transcriptional level. It also plays important roles in various life processes of NK cells, including regulating the activation and effector function of NK cells. We showed that the miRNA profiles in NK cells changed with aging, which in turn affected the development and function of NK cells. Based on the regulatory effect of miRNA on the development and function of NK cells, miRNA may serve as a potential target to protect or restore the function of NK cells in patients, thereby treating related diseases. Here, we briefly summarized recent advances on the roles of miRNA in the developmental and functional regulation of NK cells.

PB2160: ASSOCIATION OF BCL-2 EXPRESSING TUMOR CELLS WITH RESPONSE TO FRONTLINE CHEMOTHERAPY IN NODULAR SCLEROSIS HODGKIN LYMPHOMA

Background: The BCL-2 protein belongs to the family of intracellular protein factors that control the processes of apoptosis. The process of regulation of programmed cell death depends on the balance between pro- and anti-apoptotic proteins of this family. In most cases, activation of BCL-2 helps suppress apoptosis and increase the lifespan of tumor cells, as well as increase their resistance to chemotherapy. The ability to block apoptosis is a hallmark of many malignant neoplasms, including hematological ones. Classical Hodgkin lymphoma (cHL) refers to a tumor of the hematopoietic system and has a relatively good response to treatment. However, in 15-20% of cases there is a lack of response to standard first-line chemotherapy. The data available in the relative literature regarding the relationship between BCL-2 expression in tumor cells and the effectiveness of treatment are contradictory. A number of authors confirms that the detection of this protein in Hodgkin and/or Reed-Sternberg cells (HRS) is an independent factor in the adverse outcome of cHL. But the inconsistency of the data indicates the advisability of further study of the association of the expression of the specified protein factor of apoptosis with the response to 1st line therapy. Aims: To study the relationship of BCL-2 expression with the response to frontline therapy in nodular sclerosis classical Hodgkin lymphoma (NSCHL). Methods: We used formalin-fixed paraffin-embedded (FFPE) lymph node samples of 37 patients with newly diagnosed NSCHL who were treated at the clinic of KRIHBT in the period from 2006 to 2018. Depending on the response to the 1st line therapy according to the BEACOPP-14 regimen, the subjects were divided into 2 groups: group 1 (n=17) included patients who achieved complete remission (CR). Group 2 (n=20) included patients with refractoriness to the first and subsequent lines of chemotherapy or minimal response to it, or patients who received autologous or allogeneic hematopoietic stem cell transplantation. To identify BCL-2+ tumor cells an immunohistochemical staining method was used. Pathomorphological analysis and relative number counting of BCL-2+ tumor cells were performed in sequential fields of view in 100 HRS cells for each sample. Results: According to the response to 1st-line chemotherapy, differences in the relative number of BCL-2+ tumor cells were established. In patients with a partial response (PR) to treatment, the number of positive cells was statistically significantly higher than in patients with CR: 80% (58-88) vs. 24% (8-42), respectively, p<0.001. The optimal threshold value for the proportion of BCL-2+ tumor cells was 46%. Based on the established threshold, all subjects were divided into two categories: with high (≥46%) and low (<46%) BCL-2 expression. Patients with a BCL-2+ cell count ≥46% are 18.4 and 59.5 times more likely to develop a PR and an adverse course, respectively, than those with a low threshold (p<0.05). The frequency of occurrence of BCL-2+ cells above the threshold level was detected statistically significantly more often in patients with frontline treatment failures of in relation to patients with CR: 17 (81%) versus 4 (19%) patients (p<0.001). Summary/Conclusion: A high relative content of BCL-2+ tumor cells (≥46%) is associated with treatment failures in patients with NSCHL. Determining the proportion of neoplastic cells marked with this antibody could be used as an additional morphological criterion for predicting the course of the disease already at the stage of diagnosing patients in order to apply a personalized approach to therapy with BCL-2 inhibitors.

The role of IL-33/ST2 signaling in the tumor microenvironment and Treg immunotherapy.

Interleukin (IL)-33 is a tissue-derived nuclear cytokine belonging to the IL-1 family. Stimulation-2 (ST2) is the only known IL-33 receptor. ST2 signals mostly on immune cells found within tissues, such as regulatory T cells (Treg cells), CD8+ T cells, and natural killer (NK) cells. Therefore, the IL-33/ST2 signaling pathway is important in the immune system. IL-33 deficiency impairs Treg cell function. ST2 signaling is also increased in active Treg cells, providing a new approach for Treg-related immunotherapy. The IL-33/ST2 signaling pathway regulates multiple immune-related cells by activating various intracellular kinases and factors in the tumor microenvironment (TME). Here, we review the latest studies on the role of the IL-33/ST2 signaling pathway in TME and Treg immunotherapy.

Recent Advances of Fluorescence Probes for Imaging of Ferroptosis Process

Ferroptosis is an iron−dependent form of regulated cell death. It has attracted more and more research interests since it was found because of its potential physiological and pathological roles. In recent years, many efforts have been made for the developments and applications of selective fluorescence probes for real−time and in situ tracking of bioactive species during ferroptosis process, which is necessary and significant to further study the modulation mechanisms and pathological functions of ferroptosis. In this review, we will focus on summarizing the newly developed fluorescence probes that have been applied for ferroptosis imaging in the recent years, and comprehensively discussing their design strategies, including the probes for iron, reactive oxygen species, biothiols and intracellular microenvironmental factors.

Oxidative Stress and Deregulated DNA Damage Response Network in Lung Cancer Patients.

The deregulated DNA damage response (DDR) network is associated with the onset and progression of cancer. Herein, we searched for DDR defects in peripheral blood mononuclear cells (PBMCs) from lung cancer patients, and we evaluated factors leading to the augmented formation of DNA damage and/or its delayed/decreased removal. In PBMCs from 20 lung cancer patients at diagnosis and 20 healthy controls (HC), we analyzed oxidative stress and DDR-related parameters, including critical DNA repair mechanisms and apoptosis rates. Cancer patients showed higher levels of endogenous DNA damage than HC (p < 0.001), indicating accumulation of DNA damage in the absence of known exogenous genotoxic insults. Higher levels of oxidative stress and apurinic/apyrimidinic sites were observed in patients rather than HC (all p < 0.001), suggesting that increased endogenous DNA damage may emerge, at least in part, from these intracellular factors. Lower nucleotide excision repair and double-strand break repair capacities were found in patients rather than HC (all p < 0.001), suggesting that the accumulation of DNA damage can also be mediated by defective DNA repair mechanisms. Interestingly, reduced apoptosis rates were obtained in cancer patients compared with HC (p < 0.001). Consequently, the expression of critical DDR-associated genes was found deregulated in cancer patients. Together, oxidative stress and DDR-related aberrations contribute to the accumulation of endogenous DNA damage in PBMCs from lung cancer patients and can potentially be exploited as novel therapeutic targets and non-invasive biomarkers.

Enhanced Anti-Cancer Effects of Conditioned Medium from Hypoxic Human Adult Dermal Fibroblasts on Cervical Cancer Cells.

Hypoxia regulates fibroblast function by changing intracellular signaling and secretion factors, that influence the states of nearby cells. In this work, we investigated how medium (CM) from human adult dermal fibroblasts (HDFs) cultured in normoxic and hypoxic conditions affected cervical cancer (HeLa) cells. The HeLa cells showed decreased cell viability, increased apoptosis, and cell cycle arrest in response to CM from hypoxic-cultured HDFs (H-CM) compared with CM from normoxic-cultured HDFs (N-CM). Among the proteins up-regulated (>2-fold) in H-CM compared with N-CM, lymphotoxin-beta receptor (LTBR) decreased the viability of HeLa cells. Among the intracellular proteins down-regulated (>2-fold) in HeLa cells treated with H-CM compared with N-CM, the most enriched biological process GO term and KEGG pathway were protein deubiquitination and hsa05166:HTLV-I infection, respectively. In the protein–protein interaction network of intracellular proteins with altered expression (>2-fold), 1 up-regulated (TNF) and 8 down-regulated (ESR1, MCL1, TBP, CD19, LCK, PCNA, CHEK1, and POLA1) hub proteins were defined. Among the down-regulated hub proteins, the most enriched biological process GO term and KEGG pathway were leading strand elongation and hsa05166:HTLV-I infection, respectively. This study reveals that H-CM had stronger anti-cancer effects on cervical cancer cells than N-CM and induced intracellular signaling patterns related to those enhanced anti-cancer effects.

Defending and integrating an organism by the immune system.

The Integrity model proposes that the adaptive immune response defends, protects and keeps vigilance over the unity of an organism. These functions conceptually rely on three signals that can explain them. All signals have a dual character. The signal‐1 is the recognition of antigen or peptide/MHC ligand. The signal‐2 comprises either help and costimulation or suppression and coinhibition. Lastly, the signal‐3 signals tissues' condition, state or integrity. A part overlaps with the Danger‐associated molecular patterns, and the other part should be detected by putative cell‐surface molecules, intracellular factors or epigenetic events. They are called the Integrity‐associated molecular patterns (IAMPs). The IAMPs originate from damaged (positive signal‐3) or undamaged (negative signal‐3) tissues. The positive signal‐3 would induce costimulatory signal‐2, whereas the negative signal‐3 would induce coinhibitory signal‐2 in APCs. However, in analogue reality, we might more likely encounter a range of signals supposedly sensed by a group of responder cells and integrated overtime (quorum sensing). The predominant option would sway the decision of the immune system to perform either defence or protection (active tolerance). Thus, the quorum sensing supposedly delivers two qualitative thresholds for T (and B) cells' decisions to defend or suppress. If these were not attained, the vigilance (anergy) of adaptive immunocytes for T‐dependent antigens would ensue. These functions provide defence against pathogens and preservation of unity/integrity of an organism, which in turn permits protection of commensals.

Metabolic cross-talk between ovarian cancer and the tumor microenvironment-providing potential targets for cancer therapy.

Conventional treatments for ovarian cancer, including debulking cytoreductive surgery combined with carboplatin/paclitaxel-based chemotherapy, are insufficient, as evidenced by the high mortality rate, which ranks first among gynecological tumors. Therefore, there is an urgent need to develop new and effective treatment strategies. Recent evidence has shown that metabolic processes and cell behaviors in ovarian cancer are regulated by intracellular factors as well as metabolites in the tumor microenvironment (TME), which determine occurrence, proliferation, and metastasis. In this review, we describe the comprehensive landscape of metabolic cross-talk between ovarian cancer and its TME with a focus on the following four aspects: (1) intracellular metabolism based on the Warburg effect, (2) metabolism in non-tumor cells in the ovarian TME, (3) metabolic communication between tumor cells and non-tumor cells in the TME, and (4) metabolism-related therapeutic targets and agents for ovarian cancer. The metabolic cross-talk between ovarian cancer and its microenvironment involves a complex network of interactions, and interrupting these interactions by metabolic interventions is a promising therapeutic strategy.

Orphan Nuclear Receptor NR4A2 Is Constitutively Expressed in Cartilage and Upregulated in Inflamed Synovium From hTNF-Alpha Transgenic Mice.

Orphan nuclear receptor 4A2 (NR4A2/Nurr1) is a constitutively active transcription factor with potential roles in the onset and progression of inflammatory arthropathies. NR4A2 is overexpressed in synovium and cartilage from individuals with rheumatoid arthritis (RA), psoriatic arthritis, and osteoarthritis. This study documents the expression and tissue localization of NR4A2 and upstream regulator nuclear factor kappa B (NF-κB) in the human tumor necrosis factor-alpha (hTNF-α) transgenic mouse model of RA. Since TNF-α is a potent inducer of NR4A2 in vitro, we hypothesized that NR4A2 would also be upregulated and active during disease progression in this model. Expression levels of NR4A2, related receptors NR4A1 (Nur77) and 3 (NOR1), and NF-κB1 transcripts were quantified by RT-qPCR in hTNF-α and wild-type joints at three stages of disease. The protein distribution of NR4A2 and NF-κB subunit RelA (p65) was analyzed by quantitative immunohistochemistry. Global gene expression of 88 RA-related genes was also screened and compared between groups. Consistent with previous reports on the hTNF-α model, transgenic mice exhibited significant weight loss and severely swollen paws by 19 weeks of age compared to age-matched wild-type controls. NR4A1-3 and NF-κB1 were constitutively expressed at disease onset and in healthy joints. NF-κB1 transcript levels increased 2-fold in hTNF-α paws with established disease (12 weeks), followed by a 2-fold increase in NR4A2 at the late disease stage (19 weeks). NR4A2 and RelA proteins were overexpressed in inflamed synovium prior to symptoms of arthritis, suggesting that gene expression changes documented in whole paws were largely driven by elevated expression in diseased synovium. Broader screening of RA-related genes by RT-qPCR identified several differentially expressed genes in hTNF-α joints including those encoding inflammatory cytokines and chemokines, matrix-degrading enzymes and inhibitors, cell surface receptors, intracellular signaling proteins and transcription factors. Consensus binding sites for NR4A receptors and NF-κB1 were enriched in the promoters of differentially expressed genes suggesting central roles for these transcription factors in this model. This study is the first comprehensive analysis of NR4A2 in an animal model of RA and validates the hTNF-α model for testing of small molecules and genetic strategies targeting this transcription factor.

Trimethylamine N-Oxide (TMAO) Impairs Purinergic Induced Intracellular Calcium Increase and Nitric Oxide Release in Endothelial Cells.

Trimethylamine N-oxide (TMAO) is a diet derived compound directly introduced through foodstuff, or endogenously synthesized from its precursors, primarily choline, L-carnitine, and ergothioneine. New evidence outlines high TMAO plasma concentrations in patients with overt cardiovascular disease, but its direct role in pathological development is still controversial. The purpose of the study was to evaluate the role of TMAO in affecting key intracellular factors involved in endothelial dysfunction development, such as reactive oxygen species, mitochondrial health, calcium balance, and nitric oxide release using bovine aortic endothelial cells (BAE-1). Cell viability and oxidative stress indicators were monitored after acute and prolonged TMAO treatment. The role of TMAO in interfering with the physiological purinergic vasodilatory mechanism after ATP stimulation was defined through measurements of the rise of intracellular calcium, nitric oxide release, and eNOS phosphorylation at Ser1179 (eNOSSer1179). TMAO was not cytotoxic for BAE-1 and it did not induce the rise of reactive oxygen species and impairment of mitochondrial membrane potential, either in the basal condition or in the presence of a stressor. In contrast, TMAO modified the purinergic response affecting intracellular ATP-induced calcium increase, nitric oxide release, and eNOSSer1179. Results obtained suggest a possible implication of TMAO in impairing the endothelial-dependent vasodilatory mechanism.

Immunomodulation as a Protective Strategy in Chronic Otitis Media.

IntroductionMajor features of the pathogenesis in otitis media, the most common disease in childhood, include hyperplasia of the middle ear mucosa and infiltration by leukocytes, both of which typically resolve upon bacterial clearance via apoptosis. Activation of innate immune receptors during the inflammatory process leads to the activation of intracellular transcription factors (such as NF-κB, AP-1), which regulate both the inflammatory response and tissue growth. We investigated these leading signaling pathways in otitis media using mouse models, human samples, and human middle ear epithelial cell (HMEEC) lines for therapeutic immunomodulation.MethodsA stable otitis media model in wild-type mice and immunodeficient KO-mice, as well as human tissue samples from chronic otitis media, skin from the external auditory canal and middle ear mucosa removed from patients undergoing ear surgery, were studied. Gene and protein expression of innate immune signaling molecules were evaluated using microarray, qPCR and IHC. In situ apoptosis detection determined the apoptotic rate. The influence of bacterial infection on immunomodulating molecules (TNFα, MDP, Tri-DAP, SB203580, Cycloheximide) in HMEEC was evaluated. HMEEC cells were examined after bacterial stimulation/inhibition for gene expression and cellular growth.ResultsPersistent mucosal hyperplasia of the middle ear mucosa in chronic otitis media resulted from gene and protein expression of inflammatory and apoptotic genes, including NODs, TNFα, Casp3 and cleaved Casp3. In clinical chronic middle ear samples, these molecules were modulated after a specific stimulation. They also induced a hyposensitive response after bacterial/NOD-/TLR-pathway double stimulation of HMEEC cells in vitro. Hence, they might be suitable targets for immunological therapeutic approaches.ConclusionUncontrolled middle ear mucosal hyperplasia is triggered by TLRs/NLRs immunoreceptor activation of downstream inflammatory and apoptotic molecules.

Golgi quality control and autophagy

Organelles can easily be disrupted by intracellular and extracellular factors. Studies on ER and mitochondria indicate that a wide range of responses are elicited upon organelle disruption. One response thought to be of particular importance is autophagy. Cells can target entire organelles into autophagosomes for removal. This wholesale nature makes autophagy a robust means for eliminating compromised organelles. Recently, it was demonstrated that the Golgi apparatus is a substrate of autophagy. On the other hand, various reports have shown that components traffic away from the Golgi for elimination in an autophagosome-independent manner when the Golgi apparatus is stressed. Future studies will reveal how these different pieces of machinery coordinate to drive Golgi degradation. Quantitative measurements will be needed to determine how much autophagy contributes to the maintenance of the Golgi apparatus.

Explorations of tire and road wear microplastics in road dust PM2.5 at eight megacities in China

Tire and road wear microplastics (TRWMPs) in road dust are a key source of atmospheric particulate matter and have an adverse impact on human health and the environment. In this study, samples of particulate matter with a diameter of 2.5 μm or less (PM2.5) in road dust were collected from eight megacities in China to determine the TRWMP content, including that of natural rubber (NR), styrene–butadiene rubber (SBR), and butadiene rubber (BR). The total abundance of TRWMPs was the highest in Lanzhou (174.7 ± 17.0 μg g−1), followed by Xi'an (169.3 ± 23.8 μg g−1), Beijing (107.5 ± 7.5 μg g−1), Changchun (102.2 ± 8.4 μg g−1), Chengdu (101.6 ± 12.9 μg g−1), Guangzhou (98.8 ± 6.5 μg g−1), Wuhan (96.0 ± 5.3 μg g−1), and Shanghai (86.1 ± 30.1 μg g−1). A considerably higher TRWMP fraction in road dust PM2.5 was observed in the northern cities than in the southern cities and is attributable to the higher frictional resistance of roads subjected to less precipitation. The abundance of TRWMPs in the southern cities was dependent on road type, but this dependence was not observed in the northern cities. In the south, road dust PM2.5 on main roads contained more TRWMPs than that on branch roads. Correlation analysis indicated that TRWMPs were associated with tire, road, and break wear. In relation to intracellular oxidative stress factors, higher correlations were observed between TRWMPs and lactate dehydrogenase (r = 0.83) than between TRWMPs and reactive oxygen species (r = 0.59), possibly because TRWMPs destroy the integrity of the cell membrane, with NR exhibiting a higher cytotoxicity than SBR or BR. This study provides evidence that TRWMPs have an adverse impact on human health by inducing cellular oxidative stress. Therefore, further research on TRWMPs in respirable road dust is required.

Th17 CD4+ T-Cell as a Preferential Target for HIV Reservoirs.

Among CD4+ T-cells, T helper 17 (Th17) cells play a sentinel role in the defense against bacterial/fungal pathogens at mucosal barriers. However, Th17 cells are also highly susceptible to HIV-1 infection and are rapidly depleted from gut mucosal sites, causing an imbalance of the Th17/Treg ratio and impairing cytokines production. Consequently, damage to the gut mucosal barrier leads to an enhanced microbial translocation and systemic inflammation, a hallmark of HIV-1 disease progression. Th17 cells’ expression of mucosal homing receptors (CCR6 and α4β7), as well as HIV receptors and co-receptors (CD4, α4β7, CCR5, and CXCR4), contributes to susceptibility to HIV infection. The up-regulation of numerous intracellular factors facilitating HIV production, alongside the downregulation of factors inhibiting HIV, helps to explain the frequency of HIV DNA within Th17 cells. Th17 cells harbor long-lived viral reservoirs in people living with HIV (PLWH) receiving antiretroviral therapy (ART). Moreover, cell longevity and the proliferation of a fraction of Th17 CD4 T cells allow HIV reservoirs to be maintained in ART patients.

Exploring the genetic causes of isolated short stature. What has happened to idiopathic short stature?

Statural growth is underpinned by development of the growth plate during the process of endochondral ossification, which is strongly regulated by numerous local factors (intracellular, paracrine and extracellular matrix factors) and systemic factors (nutrition, hormones, proinflammatory cytokines and extracellular fluids). This explains why growth retardation can be associated with numerous pathologies, particularly genetic syndromes, hormonal or inflammatory conditions, or gastrointestinal disorders having a nutritional impact. However, in most cases (80%), no specific aetiology is found after clinical investigation and conventional additional tests have been carried out. In such cases, "idiopathic" short stature is diagnosed, which includes patients presenting with constitutional delay of growth and development and familial short stature, but also patients with very subtle constitutional skeletal dysplasia which are not easily identifiable. In recent years, new methods of genetic investigation (e.g. gene panels, exome or genome sequencing) have made it possible to identify many genetic variants associated with apparently isolated short stature. Indeed, it is still difficult to estimate the proportion of patients presenting with idiopathic short stature for which a molecular diagnosis of monogenic conditions could be made. This estimate varies hugely depending on the thoroughness of the clinical, laboratory and radiological assessments performed prior to molecular analysis, since retrospective analysis of positive cases usually reveals subtle signs of underlying syndromes or rare skeletal disorders. Molecular diagnosis in children is important to be able to offer genetic counselling and to organise patient management. Moreover, improved understanding of the molecular basis of these cases of short stature opens up numerous possibilities for more specific treatments targeting the growth plate. © 2022 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.

RNA interference-based characterization of Caspar, DREDD and FADD genes in immune signaling pathways of the red flour beetle, Tribolium castaneum (Coleoptera: Tenebrionidae)

We previously demonstrated that two immune signaling pathways, Toll and IMD, were concomitantly activated in the model beetle Tribolium castaneum by challenges to their immune system by several species of microbes, including Gram-positive and -negative bacteria as well as yeast. This contrasts with the Drosophila immune system in which more specific pathway activation depending on the type of microbe is well established. We suggest that the activation of an indiscriminate immune pathway in T. castaneum is due in part to an unselective recognition of pathogen-associated molecular patterns by the extracellular sensing modules of the two pathways. In order to obtain a more detailed understanding of the T. castaneum immune pathway, we investigated whether potential components of the T. castaneum IMD pathway, Caspar, DREDD and FADD, are involved in immune reactions triggered by microbial challenges. A sequence analysis of these three genes with the orthologues of other species, including insects, mouse and human, indicated that T. castaneum Caspar, DREDD and FADD functioned as immune signal transducers, which are usually induced by microbial challenges. However, these genes were not induced by microbial challenges. To establish whether these genes are involved in immune reactions, we used RNA interference-mediated knockdown of these genes to assess the microbial induction levels of the representative read-out antimicrobial peptide genes of the respective classes. The results indicated that these genes encode the canonical constituents of the IMD pathway of this beetle. DREDD and FADD influenced the induction of Toll-dependent antimicrobial peptide genes, providing novel crosstalk points between the two immune pathways, which appears to support indiscriminate pathway activation in T. castaneum. Furthermore, the phenotypes of DREDD or FADD knockdown pupae challenged by the two model bacterial pathogens correlated with AMP gene induction in the respective knockdowns, indicating that these intracellular factors contributed to antibacterial host defenses.

Modeling the effect of rRNA-mRNA interactions and mRNA folding on mRNA translation in chloroplasts

The process of translation initiation in prokaryotes is mediated by the hybridization of the 16S rRNA of the small ribosomal subunit with the mRNA in a short region called the ribosomal binding site. However, translation initiation in chloroplasts, which have evolved from an ancestral bacterium, is not well understood. Some studies suggest that in many cases it differs from translation initiation in bacteria and involves various novel interactions of the mRNA structures with intracellular factors; however currently, there is no generic quantitative model related to these aspects in chloroplasts.We developed a novel computational pipeline and models that can be used for understanding and modeling translation regulation in chloroplasts. We demonstrate that local folding and co-folding energy of the rRNA and the mRNA correlates with codon usage estimators of expression levels (r = −0.63) and infer predictive models that connect these energies and codon usage to protein levels (with correlation up to 0.71). In addition, we demonstrate that the ends of the transcripts in chloroplasts are populated with various structural elements that may be functional. Furthermore, we report a database of 166 novel structures in the chloroplast transcripts that are predicted to be functional.We believe that the models reported here improve existing understandings of genomic evolution and the biophysics of translation in chloroplasts; as such, they can aid gene expression engineering in chloroplasts for various biotechnological objectives.

Characteristics of leukemic stem cells in acute leukemia and potential targeted therapies for their specific eradication.

In acute myeloid leukemia (AML), a small cell population that contains stem cell features such as lack of differentiation, self-renewal potential, and drug resistance, can be identified. These so-called leukemic stem cells (LSCs) are thought to be responsible for relapse initiation after initial treatment leading to successful eradication of the bulk AML cell population. Since many studies have aimed to characterize and eliminate LSCs to prevent relapse and increase survival rates of patients, LSCs are one of the best characterized cancer stem cells. The specific elimination of LSCs, while sparing the healthy normal hematopoietic stem cells (HSCs), is one of the major challenges in the treatment of leukemia. This review focuses on several surface markers and intracellular transcription factors that can distinguish AML LSCs from HSCs and, therefore, specifically eliminate these stem cell-like leukemic cells. Moreover, previous and ongoing clinical trials of acute leukemia patients treated with therapies targeting these markers are discussed. In contrast to knowledge on LSCs in AML, insight into LSCs in acute lymphoid leukemia (ALL) is limited. This review therefore also addresses the latest insight into LSCs in ALL.

Peroxisome Proliferator-activated Receptor-γ As A Novel and Promising Target For Treating Cancer Via Regulation of Inflammation: A Brief Review.

Peroxisome proliferator activated receptors (PPARs) are a group of nuclear receptors and the ligand-activated intracellular transcription factors that are known to play a key role in physiological processes such as cell metabolism, proliferation, differentiation, tissue remodeling, inflammation, and atherosclerosis. However, in the past two decades, many reports claim that PPARs also play an imperious role as a tumor suppressor. PPAR- gamma (PPARγ), one of the best-known from the family of PPARs, is known to express in colon, breast, bladder, lung, and prostate cancer cells. Its function in tumour cells includes the modulation of several pathways involved in multiplication and apoptosis. The ligands of PPARγ act by PPARγ dependent as well as independent pathways and are also found to regulate different inflammatory mediators and transcription factors in systemic inflammation and in tumor microenvironment. Both synthetic and natural ligands that are known to activate PPARγ, suppress the tumor cell growth and multiplication through the regulation of inflammatory pathways, as found out from different functional assays and animal studies. Cancer and inflammation are interconnected processes that are now being targeted to achieve tumor suppression by decreasing the risks and burden posed by cancer cells. Therefore, PPARγ can serve as a promising target for development of clinical drug molecule attenuating the proliferation of cancer cells. In this perspective, this mini review highlights the PPARγ as a potential target for drug development aiming for anti-inflammatory and thereby suppressing tumors.

Availability of Arg, but Not tRNA, Is a Rate-Limiting Factor for Intracellular Arginylation.

Protein arginylation, mediated by arginyltransferase ATE1, is a posttranslational modification of emerging biological importance that consists of transfer of the amino acid Arg from tRNA to protein and peptide targets. ATE1 can bind tRNA and exhibits specificity toward particular tRNA types, but its dependence on the availability of the major components of the arginylation reaction has never been explored. Here we investigated key intracellular factors that can potentially regulate arginylation in vivo, including several tRNA types that show strong binding to ATE1, as well as availability of free Arg, in an attempt to identify intracellular rate limiting steps for this enzyme. Our results demonstrate that, while modulation of tRNA levels in cells does not lead to any changes in intracellular arginylation efficiency, availability of free Arg is a potentially rate-limiting factor that facilitates arginylation if added to the cultured cells. Our results broadly outline global pathways that may be involved in the regulation of arginylation in vivo.