Piezo2 Channel Upregulation is Involved in Mechanical Allodynia in CYP-Induced Cystitis Rats

Mechanical sensing Piezo2 channel in primary sensory neurons has been shown contribute to mechanical allodynia in somatic chronic pain conditions. Interstitial cystitis (IC)-associated pain is often triggered by bladder filling, a presentation that mimics the mechanical allodynia. In the present study, we aimed to examine the involvement of sensory Piezo2 channel in IC-associated mechanical allodynia using a commonly employed cyclophosphamide (CYP)-induced IC model rat. Piezo2 channels in dorsal root ganglia (DRGs) was knocked down by intrathecal injections of Piezo2 anti-sense oligodeoxynucleotides (ODNs) in CYP-induced cystitis rats, and mechanical stimulation-evoked referred bladder pain was measured in the lower abdomen overlying the bladder using von Frey filaments. Piezo2 expression at the mRNA, protein, and functional levels in DRG neurons innervating the bladder was detected by RNA-fluorescence in situ hybridization, western blotting, immunofluorescence, and Ca2+ imaging, respectively. We found that Piezo2 channels were expressed on most (> 90%) of the bladder primary afferents, including afferents that express CGRP, TRPV1 and stained with isolectin B4. CYP-induced cystitis was associated with Piezo2 upregulation in bladder afferent neurons at the mRNA, protein, and functional levels. Knockdown of Piezo2 expression in DRG neurons significantly suppressed mechanical stimulation-evoked referred bladder pain as well as bladder hyperactivity in CYP rats compared to CYP rats treated with mismatched ODNs. Our results suggest upregulation of Piezo2 channels is involved in the development of bladder mechanical allodynia and bladder hyperactivity in CYP-induced cystitis. Targeting Piezo2 might be an attractive therapeutic approach for IC-related bladder pain.

Activation of TRPA1 in Bladder Suburothelial Myofibroblasts Counteracts TGF-β1-Induced Fibrotic Changes

The activation of the transient receptor potential ankyrin 1 (TRPA1) channel has anti-fibrotic effects in the lung and intestine. Suburothelial myofibroblasts (subu-MyoFBs), a specialized subset of fibroblasts in the bladder, are known to express TRPA1. However, the role of the TRPA1 in the development of bladder fibrosis remains elusive. In this study, we use the transforming growth factor-β1 (TGF-β1) to induce fibrotic changes in subu-MyoFBs and assess the consequences of TRPA1 activation utilizing RT-qPCR, western blotting, and immunocytochemistry. TGF-β1 stimulation increased α-SMA, collagen type I alpha 1 chain(col1A1), collagen type III (col III), and fibronectin expression, while simultaneously suppressing TRPA1 in cultured human subu-MyoFBs. The activation of TRPA1, with its specific agonist allylisothiocyanate (AITC), inhibited TGF-β1-induced fibrotic changes, and part of these inhibition effects could be reversed by the TRPA1 antagonist, HC030031, or by reducing TRPA1 expression via RNA interference. Furthermore, AITC reduced spinal cord injury-induced fibrotic bladder changes in a rat model. The increased expression of TGF-β1, α-SMA, col1A1 and col III, and fibronectin, and the downregulation of TRPA1, were also detected in the mucosa of fibrotic human bladders. These findings suggest that TRPA1 plays a pivotal role in bladder fibrosis, and the negative cross talk between TRPA1 and TGF-β1 signaling may represent one of the mechanisms underlying fibrotic bladder lesions.

The enhancing effect of 5-HT on phasic contractions of human isolated distal ureter and the mechanisms mediating these effects

5-Hydroxytryptamine (5-HT) can enhance human ureteral contractions. However, the mediating receptors have not been clarified. This study sought to further characterize the mediating receptors using several selective antagonists and agonists. Human distal ureters were obtained from 92 patients undergoing cystectomy. The mRNA expression levels of 5-HT receptors were examined using RT-qPCR experiments. The phasic contractions of ureter strips, either spontaneous or evoked with neurokinin, were recorded in an organ bath. Among the 13 5-HT receptors, 5-HT_2A and 5-HT_2C receptors showed the highest mRNA expression levels. 5-HT (10-7-10-4 M) increased the frequency and baseline tension of phasic contractions in a concentration-dependent manner. However, a desensitization effect was observed. The 5-HT_2C receptor selective antagonist, SB242084 (10,30,100nM), shifted the 5-HT concentration-response curves (frequency and baseline tension) rightward with a pA2 value of 8.05 and 7.75, respectively. 5-HT_2C receptor selective agonist, vabicaserin, increased contraction frequency with an Emax of 35% of 5-HT. 5-HT_2A receptor selective antagonist, volinanserin (1,10,100 nM), only reduced baseline tension with a pA2 of 8.18. The selective antagonists of 5-HT_1A,1B, 1D, 2B, 3, 4, 5, 6, and 7 had no antagonism. Blockade of voltage-gated sodium channels, α1-adrenergic receptors, adrenergic neurotransmission, and neurokinin-2 receptors using tetrodotoxin, tamsulosin, guanethidine, and Men10376, respectively, and desensitization of sensory afferents using capsaicin (100 μM), significantly reduced 5-HT effects. We conclude that 5-HT enhanced ureteral phasic contractions mainly by activating 5-HT_2C and 5-HT_2A receptors. Sympathetic nerve and sensory afferents partly contributed to 5-HT effects. 5-HT_2C and 5-HT_2A receptors could be promising targets for ureteral stone expulsion.

Functional Expression of Transient Receptor Potential and Piezo1 Channels in Cultured Interstitial Cells of Human-Bladder Lamina Propria

The interstitial cells in bladder lamina propria (LP-ICs) are believed to be involved in sensing/afferent signaling in bladder mucosa. Transient receptor potential (TRP) cation channels act as mechano- or chemo-sensors and may underlie some of the sensing function of bladder LP-ICs. We aimed to investigate the molecular and functional expression of TRP channels implicated in bladder sensory function and Piezo1/Piezo2 channels in cultured LP-ICs of the human bladder. Bladder tissues were obtained from patients undergoing cystectomy. LP-ICs were isolated and cultured, and used for real-time reverse transcription-quantitative polymerase chain reaction, immunocytochemistry, and calcium-imaging experiments. At the mRNA level, TRPA1, TRPV2, and Piezo1 were expressed most abundantly. Immunocytochemical staining showed protein expression of TRPA1, TRPV1, TRPV2, TRPV4, TRPM8, as well as Piezo1 and Piezo2. Calcium imaging using channel agonists/antagonists provided evidence for functional expression of TRPA1, TRPV2, TRPV4, Piezo1, but not of TRPV1 or TRPM8. Activation of these channels with their agonist resulted in release of adenosine triphosphate (ATP) from LP-ICs. Inhibition of TRPV2, TRPV4 and Piezo1 blocked the stretch induced intracellular Ca²⁺ increase. Whereas inhibition of TRPA1 blocked H₂O₂ evoked response in LP-ICs. Our results suggest LP-ICs of the bladder can perceive stretch or chemical stimuli via activation of TRPV2, TRPV4, Piezo1 and TRPA1 channels. LP-ICs may work together with urothelial cells for perception and transduction of mechanical or chemical signals in human-bladder mucosa.

Transcutaneous electrical nerve stimulation and solifenacin succinate versus solifenacin succinate alone for treatment of overactive bladder syndrome: A double-blind randomized controlled study

OBJECTIVE

We evaluated a combination of transcutaneous electrical nerve stimulation (TENS) and solifenacin succinate versus solifenacin alone in the treatment of overactive bladder (OAB).

METHODS

Ninety-seven female outpatients with OAB were screened for this double-blind randomized controlled study. Eighty-six patients who met our inclusion criteria were divided randomly into two groups. In group A (43 patients), patients received oral solifenacin and "fake" TENS on the foot; in group B (43 patients), patients received oral solifenacin and effective TENS on the foot. Improvements in OAB symptoms were assessed by Overactive Bladder Symptom Score (OABSS), Overactive Bladder Questionnaire (OAB-q), voiding diaries and urodynamic tests. 70 of 86 patients (36 in group A, 34 in group B) completed the 2 months of treatment and 3 months of follow-up.

RESULTS

Statistically, the maximum bladder volume and OAB symptoms of both groups improved significantly after treatment. The improvement in group B was significantly better than that in group A, as indicated by the maximum bladder volume, OAB-q score and voiding diary. Some mild adverse effects were observed, including dry mouth, stomach upset, constipation, muscle pain and local paresthesia.

CONCLUSION

The combination of TENS and solifenacin was more effective in improving OAB symptoms than solifenacin alone.

Long non-coding DANCR targets miR-185-5p to upregulate LIM and SH3 protein 1 promoting prostate cancer via the FAK/PI3K/AKT/GSK3β/snail pathway

BACKGROUND

Long non-coding RNA differentiation antagonizing non-protein coding RNA (DANCR) acts as an oncogene in different cancers, although its roles in prostate cancer are not fully reported. We aimed to explore its mechanism in facilitating the malignancy of prostate cancer.

METHODS

The expression of DANCR, microRNA (miR)-185-5p and LIM and SH3 protein 1 (LASP1) in 40 pairs of prostate cancer tissues and normal tissues, five prostate cancer cell lines and one epithelial cell line was assessed by a quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry, respectively. In transfected PC3 and C4-2 cells, cell proliferation, migration, invasion, cell cycle distribution and epithelial-mesenchymal transition (EMT) protein expression were tested via cell counting kit-8, wound healing, transwell, flow cytometry and western blot assays, respectively. The interactions between DANCR, miR-185-5p and LASP1 were verified by a dual-luciferase reporter assay. Rescue experiments were conducted to determine the roles of DANCR on the malignant properties of PC3 and C4-2 cells. The involvement of the signaling pathway was examined using a p-FAK inhibitor.

RESULTS

DANCR and LASP1 expression was enhanced, whereas miR-185-5p expression was diminished in prostate cancer tissues and cell lines. Knockdown of DANCR suppressed cell proliferation, migration, invasion, G1-S transition and expression of EMT proteins of the transfected PC3 and C4-2 cells. DANCR sponged miR-185-5p to upregulate LASP1 expression. DANCR-miR-185-5p-LASP1 axis activates the FAK/PI3K/AKT/GSK3β/Snail pathway to promote the malignant properties of PC3 and C4-2 cells.

CONCLUSIONS

These findings suggest that DANCR exerts oncogenic roles in prostate cancer via the miR-185-5p/LASP1 axis activating the FAK/PI3K/AKT/GSK3β/Snail pathway. It can be a potential biomarker in the diagnosis and monitoring of prostate cancer.

Cell Deformation at the Air-Liquid Interface Evokes Intracellular Ca2+ Increase and ATP Release in Cultured Rat Urothelial Cells

Urothelial cells have been implicated in bladder mechanosensory transduction, and thus, initiation of the micturition reflex. Cell deformation caused by tension forces at an air-liquid interface (ALI) can induce an increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) and ATP release in some epithelial cells. In this study, we aimed to examine the cellular mechanisms underlying ALI-induced [Ca²⁺]_i increase in cultured urothelial cells. The ALI was created by stopping the influx of the perfusion but maintaining efflux. The [Ca²⁺]_i increase was measured using the Ca²⁺ imaging method. The ALI evoked a reversible [Ca²⁺]_i increase and ATP release in urothelial cells, which was almost abolished by GdCl₃. The specific antagonist of the transient receptor potential vanilloid (TRPV4) channel (HC0674) and the antagonist of the pannexin 1 channel (¹⁰panx) both diminished the [Ca²⁺]_i increase. The blocker of Ca²⁺-ATPase pumps on the endoplasmic reticulum (thapsigargin), the IP3 receptor antagonist (Xest-C), and the ryanodine receptor antagonist (ryanodine) all attenuated the [Ca²⁺]_i increase. Degrading extracellular ATP with apyrase or blocking ATP receptors (P2X or P2Y) with pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) significantly attenuated the [Ca²⁺]_i increase. Our results suggest that both Ca²⁺ influx via TRPV4 or pannexin 1 and Ca²⁺ release from intracellular Ca²⁺ stores via IP3 or ryanodine receptors contribute to the mechanical responses of urothelial cells. The release of ATP further enhances the [Ca²⁺]_i increase by activating P2X and P2Y receptors via autocrine or paracrine mechanisms.

Urinary ATP may be a biomarker for bladder outlet obstruction and its severity in patients with benign prostatic hyperplasia

Background

Urothelial cells release ATP into the urine in response to bladder stretch. Urinary ATP concentration in benign prostatic hyperplasia (BPH) patients was higher compared with asymptomatic controls. In this study, we aimed to explore the possibility that the urinary ATP level could be a non-invasive biomarker for bladder outlet obstruction (BOO) and its severity in BPH patients.

Methods

We included 117 BPH patients who underwent urodynamic studies and 109 asymptomatic controls. Urine samples at normal desire (from patients and controls), instilled fluids at maximum cystometric capacity (capacity fluid), and voided fluids during a pressure-flow study (only from patients) were collected. The ATP concentration in collected samples was measured using a luciferin-luciferase bioluminescence assay and normalized to urine creatinine (ATP/Cr). The degree of BOO was quantified using the BOO index (BOOI). Correlation between urodynamic parameters and urinary ATP concentration was analyzed in BPH patients.

Results

Urinary ATP concentration of BPH patients was significantly higher compared with controls (P<0.001). For BPH patients, a significant positive correlation was found between urinary ATP concentration and BOOI (P<0.0001). Although BPH patients with detrusor overactivity or a history of acute urinary retention had increased urinary ATP, a significant positive correlation between ATP and BOOI was also observed in these patients. When BOOI >40 was set as a cutoff point to differentiate BOO from non-BOO patients, the area under the receiver operating characteristic (ROC) curve was 0.77 (P<0.001).

Conclusions

BPH patients with BOO released higher amounts of ATP into the urine. Urinary ATP can be used as a non-invasive biomarker of BOO, and its level may also have a predictive value for the degree of obstruction.

Reduced bladder responses to capsaicin and GSK-1016790A in retired-breeder female rats with diminished volume sensitivity

Literature documents an age-related reduction of bladder sensory function. Transient receptor potential vanilloid (TRPV)1 or TRPV4 channels have been implicated in bladder mechanotransduction. To investigate contributions of TRPV1 or TRPV4 to the age-related reduction of bladder sensory function, bladder responses to capsaicin (CAP; TRPV1 agonist) and GSK-1016790A (GSK; TRPV4 agonist) in retired breeder (RB; 12-15 mo) and young adult (2-3 mo) female rats were compared using multiple methods. Metabolic cage and continuous infusion cystometry [cystometrogram (CMG)] recordings revealed that RB rats exhibit larger bladder capacity and lower voiding frequency. RB rats also have a greater intravesical pressure threshold for micturition; however, the voiding contraction strength was equivalent to that in young rats. CAP (1 μM) or GSK (20 nM) administered intravesically evoked smaller changes in all CMG parameters in RB rats. In vitro, CAP (1 μM) or GSK (20 nM) evoked smaller enhancement of bladder strip contractions, while the muscarinic receptor agonist carbachol (at 100, 300, and 1,000 nM) elicited greater amplitude contractions in RB rats. Patch-clamp recording revealed smaller CAP (100 nM) induced inward currents in bladder primary sensory neurons, and Ca²⁺ imaging revealed smaller GSK (20 nM) evoked increases in intracellular Ca²⁺ concentration in urothelial cells in RB rats. These results suggest that RB rats have a decreased bladder sensory function commonly observed in elderly women, and could be used as an animal model to study the underling mechanisms. Reduced functional expression of TRPV1 in bladder afferents or reduced functional expression of urothelial TRPV4 may be associated with the diminished sensory function.

Single i.v. ketamine augmentation of newly initiated escitalopram for major depression: results from a randomized, placebo-controlled 4-week study

BACKGROUND

While oral antidepressants reach efficacy after weeks, single-dose intravenous (i.v.) ketamine has rapid, yet time-limited antidepressant effects. We aimed to determine the efficacy and safety of single-dose i.v. ketamine augmentation of escitalopram in major depressive disorder (MDD).

METHOD

Thirty outpatients with severe MDD (17-item Hamilton Rating Scale for Depression total score ⩾ 24) were randomized to 4 weeks double-blind treatment with escitalopram 10 mg/day+single-dose i.v. ketamine (0.5 mg/kg over 40 min) or escitalopram 10 mg/day + placebo (0.9% i.v. saline). Depressive symptoms were measured using the Montgomery-Asberg Depression Rating Scale (MADRS) and the Quick Inventory of Depressive Symptomatology - Self-Report (QIDS-SR). Suicidal ideation was evaluated with the QIDS-SR item 12. Adverse psychopathological effects were measured with the Brief Psychiatric Rating Scale (BPRS)-positive symptoms, Young Mania Rating Scale (YMRS) and Clinician Administered Dissociative States Scale (CADSS). Patients were assessed at baseline, 1, 2, 4, 24 and 72 h and 7, 14, 21 and 28 days. Time to response (⩾ 50% MADRS score reduction) was the primary outcome.

RESULTS

By 4 weeks, more escitalopram + ketamine-treated than escitalopram + placebo-treated patients responded (92.3% v. 57.1%, p = 0.04) and remitted (76.9% v. 14.3%, p = 0.001), with significantly shorter time to response [hazard ratio (HR) 0.04, 95% confidence interval (CI) 0.01-0.22, p < 0.001] and remission (HR 0.11, 95% CI 0.02-0.63, p = 0.01). Compared to escitalopram + placebo, escitalopram + ketamine was associated with significantly lower MADRS scores from 2 h to 2 weeks [(peak = 3 days-2 weeks; effect size (ES) = 1.08-1.18)], QIDS-SR scores from 2 h to 2 weeks (maximum ES = 1.27), and QIDS-SR suicidality from 2 to 72 h (maximum ES = 2.24). Only YMRS scores increased significantly with ketamine augmentation (1 and 2 h), without significant BPRS or CADSS elevation.

CONCLUSIONS

Single-dose i.v. ketamine augmentation of escitalopram was safe and effective in severe MDD, holding promise for speeding up early oral antidepressant efficacy.

Evaluation of Docetaxel-Sensitive and Docetaxel-Resistant Proteomes in PC-3 Cells

OBJECTIVES

Docetaxel was the first drug with proven survival benefit in men with castration-resistant prostate cancer. Acquired resistance to docetaxel precedes fatality in castration-resistant prostate cancer. The aims of this study were to evaluate docetaxel-sensitive and docetaxel-resistant proteomes in PC-3 cells, and to investigate the molecular mechanism of docetaxel-resistant PC-3 cells.

METHODS

Docetaxel-resistant PC-3 cells were developed by docetaxel dose escalation. The global profiling of the protein expression was investigated in docetaxel-sensitive and docetaxel-resistant proteomes in PC-3 cells using 2-dimensional polyacrylamide gel electrophoresis/matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

Forty-nine differential proteins were found in docetaxel-resistant PC-3 cells in comparison with docetaxel-sensitive PC-3 cells. Expression in 29 proteins was upregulated, whereas expression in 20 proteins was downregulated. ATP synthase and galectin-1 were involved in the formation of tumor vessels; calreticulin, cathepsin D, and cofilin were involved in tumor metastasis, and GRP78 (78-kDa glucose-regulated protein) and microtubule-associated protein-6 were involved in drug resistance of tumor.

CONCLUSION

It is suggested that a proteomic expression difference exists between docetaxel-sensitive and docetaxel-resistant PC-3 cells, which would be helpful for further understanding the molecular mechanisms of docetaxel resistance in PC-3 cells.

A novel orthotopic mouse model of head and neck cancer and lymph node metastasis

Prognosis of head and neck squamous cell carcinoma (HNSCC) is largely determined by the extent of lymph node (LN) metastasis at diagnosis, and this appears to be controlled by cancer cell genetics. To examine the role of these genes in LN metastasis, we created a human-in-mouse orthotopic model of HNSCC and performed comparative microarray analysis of gene expression between populations of HNSCC cell lines derived before and after serial transplantation and in vivo metastasis in mice. Microarray analysis comparing the USC-HN3-GFP, USC-HN3-GFP-G1 and USC-HN3-GFP-G2 cell lines identified overexpression of genes implicated in epithelial-to- mesenchymal transition and the formation of cancer stem cells, including CAV-1, TLR-4 (Toll-like receptor 4), MMP-7 (matrix metalloproteinase 7), ALDH1A3, OCT-4 and TRIM-29. Ingenuity Pathway Analysis confirmed upregulation of respective gene signaling pathways in the USC-HN1-GFP-G2 cell line. Patient HNSCC samples from advanced stages overexpressed ALDH1A3, CAV-1 and MMP-7. Our results show that CAV-1, TLR-4, MMP-7, ALDH1A3, OCT-4 and TRIM-29 have increased expression in HNSCC cells selected for an enhanced metastatic phenotype and suggest that these genes may have an important role in the metastatic potential of HNSCC cells. Inhibition of these genes may therefore have prognostic and therapeutic utility in HNSCC.

Improving outcomes of acute kidney injury using mouse renal progenitor cells alone or in combination with erythropoietin or suramin

Introduction

So far, no effective therapy is available for acute kidney injury (AKI), a common and serious complication with high morbidity and mortality. Interest has recently been focused on the potential therapeutic effect of mouse adult renal progenitor cells (MRPC), erythropoietin (EPO) and suramin in the recovery of ischemia-induced AKI. The aim of the present study is to compare MRPC with MRPC/EPO or MRPC/suramin concomitantly in the treatment of a mouse model of ischemia/reperfusion (I/R) AKI.

Methods

MRPC were isolated from adult C57BL/6-gfp mice. Male C57BL/6 mice (eight-weeks old, n = 72) were used for the I/R AKI model. Serum creatinine (Cr), blood urea nitrogen (BUN) and renal histology were detected in MRPC-, MRPC/EPO-, MRPC/suramin- and PBS-treated I/R AKI mice. E-cadherin, CD34 and GFP protein expression was assessed by immunohistochemical assay.

Results

MRPC exhibited characteristics consistent with renal stem cells. The features of MRPC were manifested by Pax-2, Oct-4, vimentin, α-smooth muscle actin positive, and E-cadherin negative, distinguished from mesenchymal stem cells (MSC) by expression of CD34 and Sca-1. The plasticity of MRPC was shown by the ability to differentiate into osteoblasts and lipocytes in vitro. Injection of MRPC, especially MRPC/EPO and MRPC/suramin in I/R AKI mice attenuated renal damage with a decrease of the necrotic injury, peak plasma Cr and BUN. Furthermore, seven days after the injury, MRPC/EPO or MRPC/suramin formed more CD34⁺ and E-cadherin⁺ cells than MRPC alone.

Conclusions

These results suggest that MRPC, in particular MRPC/EPO or MRPC/suramin, promote renal repair after injury and may be a promising therapeutic strategy.

Mutation analysis of the motor neuron and pancreas homeobox 1 (MNX1, former HLXB9) gene in Swedish patients with Currarino syndrome

BACKGROUND

Currarino syndrome (CS) is a triad consisting of partial sacral agenesis, presacral mass, and anorectal malformations, typically anal stenosis but the phenotype varies. The main cause of this monogenic disorder is mutations in the motor neuron and pancreas homeobox 1 gene. We describe the clinical and genetic findings in 4 unrelated Swedish cases with CS and their relatives.

METHODS

We performed mutation analysis of the motor neuron and pancreas homeobox 1 gene in 4 cases with CS by DNA sequence analysis as well as multiplex ligation-dependent probe amplification. In addition, array comparative genome hybridization was performed in 2 cases. Including relatives, totally, 14 individuals were analyzed.

RESULTS

We found 2 previously described mutations, 1 de novo nonsense mutation (p.Gln212X) and 1 maternally inherited frameshift mutation (p.Pro18ProfsX38). In the family with the frameshift mutation, we also detected the same maternally inherited mutation in 3 of the proband's 4 brothers, who displayed varying symptoms. All mutation carriers had presacral tumors, although 2 were asymptomatic.

CONCLUSION

Our findings emphasize the need for genetic counseling and mutation analysis in patients with CS to detect tumors early. It shows the importance of evaluation of the sacrum and the presacral region in patients with anal stenosis with or without funnel anus. Family members of index cases should be considered for evaluation even if they are asymptomatic.

[K562 cells differentiation induced by RNA from rabbit reticulocytes]

OBJECTIVE

To study the effect of RNA from the reticulocytes of rabbit on cell differentiation of human leukemia cell line K562 cells.

METHOD

RNA from rabbit reticulocytes and human leukemia K562 cells were cultured for 4 days to detect cellular changes.

RESULTS

When K562 cells grew in a medium containing 100 micrograms/ml RNA, the cellular growth and division were gradually suppressed and the cells changed toward a differentiated phenotype. Subsequently, K562 cells produced hemoglobins and further differentiated terminally.

CONCLUSION

RNA of mammalian erythrocyte played a role in declining cellular division and growth of K562 cells, reversing malignant phenotype, and promoting differentiation.

Cryptosporidium parvum infection of intestinal epithelium: morphologic and functional studies in an in vitro model

A monolayer of mature polarized colonic epithelial cells (T84) able to generate and maintain a barrier to macromolecular flow was used to study pathophysiologic events that occur on microvillus cell exposure to Cryptosporidium parvum. By 24-48 h, several life cycle forms were seen in parasitophorous vacuoles near the apical cell surface, along with a time- and oocyst dose-dependent reduction in epithelial barrier function. As few as 10(5) organisms constituted a successful infecting dose, and heat inactivation of organisms markedly reduced the monolayer barrier alteration. Horseradish peroxidase flux studies demonstrated a substantial increase in macromolecular permeability of the monolayer, and lactate dehydrogenase determinations indicated modest injury of the T84 epithelial cells on exposure to oocysts. Thus, disruption of the epithelial cell barrier, not just opening of transcellular channels for ion flow as reported previously, is responsible for the effects of C. parvum oocysts on intestinal epithelium.