Prevalence of breast cancer in rural population of Jaipur: a survey-based observational study.

Breast cancer, a global health concern predominantly affecting women, recorded 2.3 million new cases and 685,000 deaths in 2020. Alarmingly, projections suggest that by 2040, there could be over 3 million new cases and 1 million deaths. To assess breast cancer prevalence in 24 rural villages within a 60 km radius of NIMS Hospital, Tala Mod, Jaipur, Rajasthan, North India 303,121. A study involving 2023 participants conducted initial screenings, and positive cases underwent further tests, including ultrasound, mammography, and biopsy. SPSSv28 analysed collected data. Among 2023 subjects, 3 screened positive for breast lumps. Subsequent clinical examination and biopsy identified 1 normal case and 2 with breast cancer, resulting in a prevalence proportion of 0.0009 or 98 per 100,000. This study helps fill gap in breast cancer prevalence data for rural Rajasthan. The results highlight a concerning prevalence of breast cancer in the rural area near NIMS hospital, emphasizing the urgent need for increased awareness, early detection, and better healthcare access. Challenges like limited resources, awareness programs, and delayed diagnosis contribute to this high incidence. To address this, comprehensive approach is necessary, including improved screening programs and healthcare facilities in rural areas. Prioritizing rural healthcare and evidence-based strategies can reduce the burden of breast cancer and improve health outcomes.

Folate-Mediated Targeting and Controlled Release: PLGA-Encapsulated Mesoporous Silica Nanoparticles Delivering Capecitabine to Pancreatic Tumor.

The discovery of specifically tailored therapeutic delivery systems has sparked the interest of pharmaceutical researchers considering improved therapeutic effectiveness and fewer adverse effects. The current study concentrates on the design and characterization of PLGA (polylactic-co-glycolic acid) capped mesoporous silica nanoparticles (MSN)-based systems for drug delivery for pH-sensitive controlled drug release in order to achieve a targeted drug release inside the acidic tumor microenvironment. The physicochemical properties of the nanoformulations were analyzed using TEM, zeta potential, AFM, TGA, FTIR, and BET analyses in addition to DLS size. The final formed PLGA-FoA-MSN-CAP and pure MSN had sizes within the therapeutic ranges of 164.5 ± 1.8 and 110.7 ± 2.2, respectively. Morphological characterization (TEM and AFM) and elemental analysis (FTIR and XPS) confirmed the proper capping and tagging of PLGA and folic acid (FoA). The PLGA-coated FoA-MSN exhibited a pH-dependent controlled release of the CAP (capecitabine) drug, showing efficient release at pH 6.8. Furthermore, the in vitro MTT test on PANC1 and MIAPaCa-2 resulted in an IC50 value of 146.37 µg/ml and 105.90 µg/ml, respectively. Mitochondrial-mediated apoptosis was confirmed from the caspase-3 and annexin V/PI flow cytometry assay, which displayed a cell cycle arrest at the G1 phase. Overall, the results predicted that the designed nanoformulation is a potential therapeutic agent in treating pancreatic cancer.

Cis-regulatory effect of HPV integration is constrained by host chromatin architecture in cervical cancers.

Human papillomavirus (HPV) infections are the primary drivers of cervical cancers, and often HPV DNA gets integrated into the host genome. Although the oncogenic impact of HPV encoded genes is relatively well known, the cis-regulatory effect of integrated HPV DNA on host chromatin structure and gene regulation remains less understood. We investigated genome-wide patterns of HPV integrations and associated host gene expression changes in the context of host chromatin states and topologically associating domains (TADs). HPV integrations were significantly enriched in active chromatin regions and depleted in inactive ones. Interestingly, regardless of chromatin state, genomic regions flanking HPV integrations showed transcriptional upregulation. Nevertheless, upregulation (both local and long-range) was mostly confined to TADs with integration, but not affecting adjacent TADs. Few TADs showed recurrent integrations associated with overexpression of oncogenes within them (e.g. MYC, PVT1, TP63 and ERBB2) regardless of proximity. Hi-C and 4C-seq analyses in cervical cancer cell line (HeLa) demonstrated chromatin looping interactions between integrated HPV and MYC/PVT1 regions (~ 500 kb apart), leading to allele-specific overexpression. Based on these, we propose HPV integrations can trigger multimodal oncogenic activation to promote cancer progression.

Disentangling the enigmatic role of ephrin signaling in chronic pain: Moving towards future anti-pain therapeutics.

Chronic pain is a common and debilitating condition with a huge social and economic burden worldwide. Currently, available drugs in clinics are not adequately effective and possess a variety of severe side effects leading to treatment withdrawal and poor quality of life. The ongoing search for new therapeutics with minimal side effects for chronic pain management remains a high research priority. Erythropoietin-producing human hepatocellular carcinoma cell receptor (Eph) is a tyrosine kinase receptor that is involved in neurodegenerative disorders, including pain. The Eph receptor interacts with several molecular switches, such as N methyl d-aspartate receptor (NMDAR), mitogen-activated protein kinase (MAPK), calpain 1, caspase 3, protein kinase a (PKA), and protein kinase Cy (PKCy), which in turn regulates pathophysiology of chronic pain. Here we highlight the emerging evidence of the Ephs/ephrin system as a possible near-future therapeutic target for the treatment of chronic pain and discuss the various mechanism of its involvement. We critically analyse the present status of Eph receptor system and conclude that extrapolating the pharmacological and genetic approaches using a strong therapeutic development framework could serve as next-generation analgesics for the management of chronic pain.

Nanovaccine: A Hope to Triumph the Battle Against Novel Coronavirus Disease 2019 (COVID-19).

BACKGROUND: The novel coronavirus 2019 (COVID-19) infection has caused the global emergence of coronavirus in humans during the last 12 months. Till May 11, 2021, the confirmed global COVID-19 cases and deaths reached 158551526 and 3296855, respectively. METHODS: Goblet cells and ciliated cells in the nose act as the initial infection site of SARS-CoV-2. Thus, mucus immunity is important to protect from infection. The outburst of SARS-CoV-2 infection can be halted only when an effective vaccine will be developed. RESULTS: Globally, over 100 different vaccines are under investigation, including DNA vaccines, RNA vaccines, inactivated virus vaccines, adenovirus-based vaccines, recombinant/subunit protein vaccines, peptide vaccines, virus-like particles, etc. Inactivated virus vaccines and mRNA, and adenovirus-based vaccines have moved fast into patent clinical trials. CONCLUSION: Vaccines containing spike protein of SARS-CoV as subunit could effectively prevent binding of coronavirus to the host cell and membrane fusion. Thus, spike protein can be used as a major target for subunit vaccine preparation.

Interplay of the transcription factor MRTF-A and matrix stiffness controls mammary acinar structure and protrusion formation.

BACKGROUND: Ongoing differentiation processes characterize the mammary gland during sexual development and reproduction. In contrast, defective remodelling is assumed to be causal for breast tumorigenesis. We have shown recently that the myocardin-related transcription factor A (MRTF-A) is essential for forming regular hollow acinar structures. Moreover, MRTF-A activity is known to depend on the biochemical and physical properties of the surrounding extracellular matrix. In this study we analysed the mutual interaction of different matrix stiffnesses and MRTF-A activities on formation and maintenance of mammary acini. METHODS: Human MCF10A acini and primary mature organoids isolated from murine mammary glands were cultivated in 3D on soft and stiff matrices (200-4000 Pa) in conjunction with the Rho/MRTF/SRF pathway inhibitor CCG-203971 and genetic activation of MRTF-A. RESULTS: Three-dimensional growth on stiff collagen matrices (> 3000 Pa) was accompanied by increased MRTF-A activity and formation of invasive protrusions in acini cultures of human mammary MCF10A cells. Differential coating and synthetic hydrogels indicated that protrusion formation was attributable to stiffness but not the biochemical constitution of the matrix. Stiffness-induced protrusion formation was also observed in preformed acini isolated from murine mammary glands. Acinar outgrowth in both the MCF10A acini and the primary organoids was partially reverted by treatment with the Rho/MRTF/SRF pathway inhibitor CCG-203971. However, genetic activation of MRTF-A in the mature primary acini also reduced protrusion formation on stiff matrices, whilst it strongly promoted luminal filling matrix-independently. CONCLUSION: Our results suggest an intricate crosstalk between matrix stiffness and MRTF-A, whose activity is required for protrusion formation and sufficient for luminal filling of mammary acini. Video Abstract.

Mass Spectrometry-Based Technology and Workflows for Studying the Chemistry of Fungal Endophyte Derived Bioactive Compounds.

Bioactive compounds have gained substantial attention in research and have conferred great advancements in the industrial and pharmacological fields. Highly diverse fungi and their metabolome serve as a big platform to be explored for their diverse bioactive compounds. Omics tools coupled with bioinformatics, statistical, and well-developed algorithm tools have elucidated immense knowledge about fungal endophyte derived bioactive compounds. Further, these compounds are subjected to chromatography-gas chromatography and liquid chromatography (LC), spectroscopy-nuclear magnetic resonance (NMR), and "soft ionization" technique-matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) based analytical techniques for structural characterization. The mass spectrometry (MS)-based approach, being highly sensitive, reproducible, and reliable, produces quick and high-profile identification. Coupling these techniques with MS has resulted in a descriptive account of the identification and quantification of fungal endophyte derived bioactive compounds. This paper emphasizes the workflows of the above-mentioned techniques, their advancement, and future directions to study the unraveled area of chemistry of fungal endophyte-derived bioactive compounds.

An interdependent network of functional enhancers regulates transcription and EZH2 loading at the INK4a/ARF locus.

The INK4a/ARF locus encodes important cell-cycle regulators p14ARF, p15INK4b, and p16INK4a. The neighboring gene desert to this locus is the most reproducible GWAS hotspot that harbors one of the densest enhancer clusters in the genome. However, how multiple enhancers that overlap with GWAS variants regulate the INK4a/ARF locus is unknown, which is an important step in linking genetic variation with associated diseases. Here, we show that INK4a/ARF promoters interact with a subset of enhancers in the cluster, independent of their H3K27ac and eRNA levels. Interacting enhancers transcriptionally control each other and INK4a/ARF promoters over long distances as an interdependent single unit. The deletion of even a single interacting enhancer results in an unexpected collapse of the entire enhancer cluster and leads to EZH2 enrichment on promoters in an ANRIL-independent manner. Dysregulated genes genome-wide mimic 9p21-associated diseases under these scenarios. Our results highlight intricate dependencies of promoter-interacting enhancers on each other.

Exome sequencing identifies ARID2 as a novel tumor suppressor in early-onset sporadic rectal cancer.

Early-onset sporadic rectal cancer (EOSRC) is a unique and predominant colorectal cancer (CRC) subtype in India. In order to understand the tumorigenic process in EOSRC, we performed whole-exome sequencing of 47 microsatellite stable EOSRC samples. Signature 1 was the predominant mutational signature in EOSRC, as previously shown in other CRC exome studies. More importantly, we identified TP53, KRAS, APC, PIK3R1, SMAD4 and ZNF880 as significantly mutated (q < 0.1) and ARID1A and ARID2 as near-significantly mutated (restricted hypothesis testing; q < 0.1) candidate drivers. Unlike the other candidates, the tumorigenic potential of ARID2, encoding a component of the SWI/SNF chromatin remodeling complex, is largely unexplored in CRC. shRNA-mediated ARID2 knockdown performed in different CRC cell lines resulted in significant alterations in transcript levels of cancer-related target genes. More importantly, ARID2 knockdown promoted several tumorigenic features including cell viability, proliferation, ability to override contact inhibition of growth, and migration besides significantly increasing tumor formation ability in nude mice. The observed gain in tumorigenic features was rescued upon ectopic expression of wild type but not mutant ARID2. Analyses of the TCGA pan-cancer dataset revealed several modes of ARID2 inactivation and of the CRC dataset revealed poorer survival in patients with ARID2 alterations. We therefore propose ARID2 as a novel tumor suppressor in CRC.

A rare variant of African ancestry activates 8q24 lncRNA hub by modulating cancer associated enhancer.

Genetic variation at the 8q24 locus is linked with the greater susceptibility to prostate cancer in men of African ancestry. One such African ancestry specific rare variant, rs72725854 (A>G/T) (~6% allele frequency) has been associated with a ~2-fold increase in prostate cancer risk. However, the functional relevance of this variant is unknown. Here we show that the variant rs72725854 is present in a prostate cancer-specific enhancer at 8q24 locus. Chromatin-conformation capture and dCas9 mediated enhancer blocking establish a direct regulatory link between this enhancer and lncRNAs PCAT1, PRNCR1 and PVT1. The risk allele ('T') is associated with higher expression of PCAT1, PVT1 and c-myc in prostate tumors. Further, enhancer with the risk allele gains response to androgen stimulation by recruiting the transcription factor SPDEF whereas, non-risk alleles remain non-responsive. Elevated expression of these lncRNAs and c-myc in risk allele carriers may explain their greater susceptibility to prostate cancer.

Recent technological advancements in stem cell research for targeted therapeutics.

Stem cells have characteristic features of self-renewal, pluripotency and differentiation, which are responsible for replenishment of tissue or organ. Stem cells are potentiated as therapeutic tool in drug targeting and regenerative medicine-from curing various neurological diseases and malignancies to congenital diseases. These technological advancements have established stem cells as future of medicine. However, due to ethico-social limitations, the use of embryonic stem cells (ESCs) has been avoided, while physiological availability of adult stem cells (ASCs) and induced pluripotent stem cells (iPSCs) has gained appropriate preference. These iPSCs are very much similar to ESCs in terms of their self-renewal and pluripotency. Here, we have summarized the technologies that have established stem cells isolation, their molecular marker and factors responsible for their maintenance. Different cellular (transcription factors, regulatory proteins, miRNA like miRNA-296, miRNA-145, etc.) and extracellular components transcend stem cell fate. Their identification and characterization involve development and efficient utilization of tools like magnetic activated cell sorting (MACS) and fluorescence activated cell sorting (FACS). Some of the technologies have been patented and spin-off's based on them have been commercialized. In conclusion, we present the future scope and possibilities that stem cell technologies behold for us. Graphical abstract Pictorial representation of therapeutic approaches for disease treatment using stem cell technology. Disease-specific adult stem cells are isolated along with niche cells by utilizing tools like FACS/MACS/LCM, etc. Thereafter, cells are reprogrammed through introduction of Yamanaka factors (Oct3/4, Sox2, c-myc, Klf4) to make induced pluripotent stem cell (iPSCs). The disease-specific iPSCs undergo genetic modification after delivery of therapeutic gene through retroviral vehicle. The genetically modified cells are introduced back in person with disease for therapeutic effects. FACS, fluorescence activated cell sorting; MACS, magnetic-activated cell sorting; LCM, laser capture microdissection; Oct3/4, octamer-binding transcription factor 3/4; Sox2, sex determining region Y-box 2; Klf4, Kruppel-like factor 4.

Ligand dependent gene regulation by transient ERα clustered enhancers.

Unliganded Estrogen receptor alpha (ERα) has been implicated in ligand-dependent gene regulation. Upon ligand exposure, ERα binds to several EREs relatively proximal to the pre-marked, unliganded ERα-bound sites and affects transient but robust gene expression. However, the underlying mechanisms are not fully understood. Here we demonstrate that upon ligand stimulation, persistent sites interact extensively, via chromatin looping, with the proximal transiently ERα-bound sites, forming Ligand Dependent ERα Enhancer Cluster in 3D (LDEC). The E2-target genes are regulated by these clustered enhancers but not by the H3K27Ac super-enhancers. Further, CRISPR-based deletion of TFF1 persistent site disrupts the formation of its LDEC resulting in the loss of E2-dependent expression of TFF1 and its neighboring genes within the same TAD. The LDEC overlap with nuclear ERα condensates that coalesce in a ligand and persistent site dependent manner. Furthermore, formation of clustered enhancers, as well as condensates, coincide with the active phase of signaling and their later disappearance results in the loss of gene expression even though persistent sites remain bound by ERα. Our results establish, at TFF1 and NRIP1 locus, a direct link between ERα condensates, ERα enhancer clusters, and transient, but robust, gene expression in a ligand-dependent fashion.

In Vivo Toxicity Study of Ethanolic Extracts of Evolvulus alsinoides & Centella asiatica in Swiss Albino Mice.

AIM: We aimed to investigate several parameters after the in vivo acute and sub-acute administration of ethanolic extracts from E. alsinoides & C. asiatica. METHODS: Malignant Ovarian Germ Cell Tumors for in vivo toxicity study guidelines 423 and 407 of Organization for Economic Co-operation and Development (OECD) were followed for acute and sub-acute toxicity assays respectively. For LD50 evaluation, a single dose of ethanolic extracts of Evolvulus alsinoides L. (EEA) and ethanolic extracts of Centella asiatica (ECA) was orally administered to mice at doses of 200, 400, 800, 1600 and 2000 mg/kg. Then the animals were observed for 72 hours. For acute toxicity evaluation, a single dose of both extracts was orally administered to mice at doses of 300, 600, 1200 and 2000 mg/kg and the animals were observed for 14 days. In the sub-acute study, the extracts were orally administered to mice for 28 days at doses of 300, 600, 1200 and 2000 mg/kg. To assess the toxicological effects, animals were closely observed on general behaviour, clinical signs of toxicity, body weight, food and water intake. At the end of the study, it was performed biochemical and hematological evaluations, as well as histopathological analysis from the following organs: brain, heart, liver, and kidney. RESULTS: The oral administration of E. alsinoides and C. asiatica ethanolic extracts, i.e. EEA 300, EEA 600, EEA 1200, EEA 2000, ECA 300, ECA 600, ECA 1200 & ECA 2000 mg/kg doses showed no moral toxicity effect in LD50, acute and sub-acute toxicity parameters. CONCLUSION: In this study, we had found that E. alsinoides & C. asiatica extract at different doses cause no mortality in acute and sub-acute toxicity study. Also, histopathology of kidney, liver, heart, and brain showed no alterations in tissues morphology.

Paradoxical reaction in tuberculous meningitis: presentation, predictors and impact on prognosis.

BACKGROUND: Awareness about paradoxical reactions in tuberculous meningitis is crucial as a paradoxical reaction may lead to certain wrong conclusions (for example, an erroneous diagnosis, and a possibility of treatment failure, mycobacterial drug-resistance, drug toxicity, or presence of a malignancy). The present study was planned to evaluate the incidence and predictive factors of paradoxical reactions in light of clinical, cerebrospinal fluid, and neuroimaging characteristics. METHODS: In this prospective cohort study, consecutive patients fulfilling the International Consensus criteria of tuberculous meningitis were included. Patients were subjected to clinical evaluation, cerebrospinal fluid evaluation, and neuroimaging. Patients were treated with anti-tuberculosis drugs along with corticosteroids. Patients were regularly followed up at 3 monthly intervals. At each follow up patients were evaluated clinically and repeat cerebrospinal fluid analysis was performed along with repeat neuroimaging. Disability assessment was done using Barthel index. RESULTS: We enrolled 141 patients of tuberculous meningitis. Approximately one-third of patients (44/141; 31.2 %) developed a paradoxical reaction. Twenty-seven patients developed hydrocephalus, 26 developed tuberculomas, 12 developed optochiasmatic arachnoiditis and 4 patients had spinal arachnoiditis. In 41 patients (out of 44) cerebrospinal fluid paradoxically worsened (increase in cells and/or protein); 2 demonstrated a decrease in cells with polymorph predominance while in one it was normal. In 3 patients, paradoxical cerebrospinal fluid changes were not associated with neuroimaging changes. On multivariate analysis, predictors of paradoxical reaction were female gender (p = 0.013), HIV positivity (p = 0.01) and a shorter duration of illness (p = 0.049). Development of paradoxical reactions did not predict the disability status of the patients. CONCLUSIONS: Paradoxical reaction occurs in approximately one-third of patients with tuberculous meningitis. Female gender, concomitant HIV infection, and a shorter duration of illness were significant predictors. Paradoxical reactions did not adversely affect the outcome.

Evidence for a causal link between adaptor protein PDZK1 downregulation and Na⁺/H⁺ exchanger NHE3 dysfunction in human and murine colitis.

A dysfunction of the Na(+)/H(+) exchanger isoform 3 (NHE3) significantly contributes to the reduced salt absorptive capacity of the inflamed intestine. We previously reported a strong decrease in the NHERF family member PDZK1 (NHERF3), which binds to NHE3 and regulates its function in a mouse model of colitis. The present study investigates whether a causal relationship exists between the decreased PDZK1 expression and the NHE3 dysfunction in human and murine intestinal inflammation. Biopsies from the colon of patients with ulcerative colitis, murine inflamed ileal and colonic mucosa, NHE3-transfected Caco-2BBe colonic cells with short hairpin RNA (shRNA) knockdown of PDZK1, and Pdzk1-gene-deleted mice were studied. PDZK1 mRNA and protein expression was strongly decreased in inflamed human and murine intestinal tissue as compared to inactive disease or control tissue, whereas that of NHE3 or NHERF1 was not. Inflamed human and murine intestinal tissues displayed correct brush border localization of NHE3 but reduced acid-activated NHE3 transport activity. A similar NHE3 transport defect was observed when PDZK1 protein content was decreased by shRNA knockdown in Caco-2BBe cells or when enterocyte PDZK1 protein content was decreased to similar levels as found in inflamed mucosa by heterozygote breeding of Pdzk1-gene-deleted and WT mice. We conclude that a decrease in PDZK1 expression, whether induced by inflammation, shRNA-mediated knockdown, or heterozygous breeding, is associated with a decreased NHE3 transport rate in human and murine enterocytes. We therefore hypothesize that inflammation-induced loss of PDZK1 expression may contribute to the NHE3 dysfunction observed in the inflamed intestine.

Pseudomonas aeruginosa reduces the expression of CFTR via post-translational modification of NHERF1.

Pseudomonas aeruginosa infections of the airway cells decrease apical expression of both wild-type (wt) and F508del CFTR through the inhibition of apical endocytic recycling. CFTR endocytic recycling is known to be regulated by its interaction with PDZ domain containing proteins. Recent work has shown that the PDZ domain scaffolding protein NHERF1 finely regulates both wt and F508delCFTR membrane recycling. Here, we investigated the effect of P. aeruginosa infection on NHERF1 post-translational modifications and how this affects CFTR expression in bronchial epithelial cells and in murine lung. Both in vitro in bronchial cells, and in vivo in mice, infection reduced CFTR expression and increased NHERF1 molecular weight through its hyper-phosphorylation and ubquitination as a consequence of both bacterial pilin- and flagellin-mediated host-cell interaction. The ability of P. aeruginosa to down-regulate mature CFTR expression was reduced both in vivo in NHERF1 knockout mice and in vitro after silencing NHERF1 expression or mutations blocking its phosphorylation at serines 279 and 301. These studies provide the first evidence that NHERF1 phosphorylation may negatively regulate its action and, therefore, the assembly and function of multiprotein NHERF1 complexes in response to infection. The identification of molecular mechanisms responsible for these effects could identify novel targets to block potential P. aeruginosa interference with the efficacy of potentiator and/or corrector compounds.

Molecular transport machinery involved in orchestrating luminal acid-induced duodenal bicarbonate secretion in vivo.

The duodenal villus brush border membrane expresses several ion transporters and/or channels, including the solute carrier 26 anion transporters Slc26a3 (DRA) and Slc26a6 (PAT-1), the Na(+)/H(+) exchanger isoform 3 (NHE3), as well as the anion channels cystic fibrosis transmembrane conductance regulator (CFTR) and Slc26a9. Using genetically engineered mouse models lacking Scl26a3, Slc26a6, Slc26a9 or Slc9a3 (NHE3), the study was carried out to assess the role of these transporters in mediating the protective duodenal bicarbonate secretory response (DBS-R) to luminal acid; and to compare it to their role in DBS-R elicited by the adenylyl cyclase agonist forskolin. While basal DBS was reduced in the absence of any of the three Slc26 isoforms, the DBS-R to forskolin was not altered. In contrast, the DBS-R to a 5 min exposure to luminal acid (pH 2.5) was strongly reduced in the absence of Slc26a3 or Slc26a9, but not Slc26a6. CFTR inhibitor [CFTR(Inh)-172] reduced the first phase of the acid-induced DBS-R, while NHE3 inhibition (or knockout) abolished the sustained phase of the DBS-R. Luminal acid exposure resulted in the activation of multiple intracellular signalling pathways, including SPAK, AKT and p38 phosphorylation. It induced a biphasic trafficking of NHE3, first rapidly into the brush border membrane, followed by endocytosis in the later stage. We conclude that the long-lasting DBS-R to luminal acid exposure activates multiple duodenocyte signalling pathways and involves changes in trafficking and/or activity of CFTR, Slc26 isoforms Slc26a3 and Slc26a9, and NHE3.

Rescue of epithelial HCO3- secretion in murine intestine by apical membrane expression of the cystic fibrosis transmembrane conductance regulator mutant F508del.

This study investigated whether expression of the common cystic fibrosis transmembrane conductance regulator (CFTR) mutant F508del in the apical membrane of enterocytes confers increased bicarbonate secretory capacity on the intestinal epithelium of F508del mutant mice compared to that of CFTR knockout (KO) mice. CFTR KO mice, F508del mutant mice (F508del) and wild-type (WT) littermates were bred on the FVB/N background. F508del isolated brush border membrane (BBM) contained approximately 5-10% fully glycosylated band C protein compared to WT BBM. Similarly, the forskolin (FSK)-induced, CFTR-dependent short-circuit current (I(sc)) of F508del mucosa was approximately 5-10% of WT, whereas the HCO(3)(-) secretory response ( ) was almost half that of WT in both duodenum and mid-colon studied in vitro and in vivo. While WT intestine retained full FSK-induced in the absence of luminal Cl(-), the markedly higher than I(sc) in F508del intestine was dependent on the presence of luminal Cl(-), and was blocked by CFTR inhibitors. The Ste20-related proline-alanine-rich kinases (SPAK/OSR1), which are downstream of the with-no-lysine (K) protein kinases (WNK), were rapidly phosphorylated by FSK in WT and F508del, but significantly more slowly in CFTR KO intestine. In conclusion, the data demonstrate that low levels of F508del membrane expression in the intestine of F508del mice significantly increased FSK-induced HCO(3)(-) secretion mediated by Cl(-)/HCO(3)(-) exchange. However, in WT mucosa FSK elicited strong SPAK/OSR1 phosphorylation and Cl(-)-independent HCO(3)(-) efflux. This suggests that therapeutic strategies which deliver F508del to the apical membrane have the potential to significantly enhance epithelial HCO(3)(-) secretion.

Loss of downregulated in adenoma (DRA) impairs mucosal HCO3(-) secretion in murine ileocolonic inflammation.

BACKGROUND: Ileocolonic luminal pH has been reported to be abnormally low in inflammatory bowel disease (IBD) patients, and one of the causative factors may be reduced epithelial HCO(3)(-) secretory rate (J(HCO3)(-)). Disturbances in J(HCO3)(-) may occur due to inflammation-induced changes in the crypt and villous architecture, or due to the effect of proinflammatory cytokines on epithelial ion transporters. METHODS: To discriminate between these possibilities, the tumor necrosis factor alpha (TNF-α) overexpressing (TNF(+/ΔARE)) mouse model was chosen, which displays high proinflammatory cytokine levels in both ileum and colon, but develops only mild colonic histopathology and diarrhea. HCO(3)(-) secretion, mRNA expression, immunohistochemistry, and fluid absorptive capacity were measured in ileal and mid-colonic mucosa of TNF(+/ΔARE) and wildtype (WT) (TNF(+/+)) mice in Ussing chambers, and in anesthetized mice in vivo. RESULTS: The high basal J(HCO3)(-) observed in WT ileal and mid-colonic mucosa were luminal Cl(-) -dependent and strongly decreased in TNF(+/ΔARE) mice. Downregulated in adenoma (DRA) mRNA and protein expression was strongly decreased in TNF(+/ΔARE) ileocolon, whereas cystic fibrosis transmembrane conductance regulator (CFTR), Na(+) /H(+) exchanger 3 (NHE3), Na(+) /HCO(3)(-) cotransporter (NBC), and epithelial sodium channel (ENaC) expression was not significantly altered. This indicates that the severe defect in ileocolonic J(HCO3)(-) was due to DRA downregulation. Fluid absorption was severely depressed in the ileum but only mildly affected in the mid-distal colon, preventing the development of overt diarrhea. CONCLUSIONS: Even mild ileocolonic inflammation may result in a decrease of epithelial HCO(3)(-) secretion, which may contribute to alterations in surface pH, intestinal flora, and mucus barrier properties.

Cytoprotective effects of acidosis via heat shock protein HSP27 against the anticancer drug doxorubicin.

Drug resistance continues to be a stumbling block in achieving better cure rates in several cancers. Doxorubicin is commonly used in treatment of a wide range of cancers. The aim of this study was to look into the mechanisms of how low ambient pH may contribute to down-regulation of apoptotic pathways in a gastric tumour cell line. Low pH culture conditions were found to dramatically prolong cell survival after doxorubicin treatment, an effect that was in part reversed by co-incubation with the specific p38 mitoge-activated protein kinase (MAP kinase) inhibitor SB203580, only mildly inhibited by blockade of the multi-drug resistance 1 (MDR1) transporter, but completely abolished by siRNA-mediated knockdown of the heat shock protein 27 (HSP27). In conclusion, acidic pH causes less accumulation of cytotoxic drug in the nucleus of adeno gastric carcinoma (AGS) cells and HSP27-dependent decrease in FasR-mediated gastric epithelial tumour cell apoptosis.