Pharmacokinetic and pharmacodynamic evaluation of a new sustained-release capsules using starch-sponge matrix (SSM) release system for nifedipine in rats

We conducted a performance assessment study for a new sustained-release capsule including starch-sponge matrix (SSM). The SSM, which is a support medium for drug release, was made from 2.5% cornstarch glue by means of freezing dry method. The SSM capsule was applied for nifedipine (NFP), a calcium channel blocker, and evaluated pharmacokinetic and pharmacodynamic (PK/PD) profiles of NFP after intraduodenal administration of SSM capsules including 2.5 or 5.0 mg of NFP per capsule to rats. Plasma NFP concentrations from the SSM capsules showed dose-dependent increases with a Michaelis-Menten like behavior over 360 minutes after intraduodenal administration. The values of area under the concentration vs. time curve from time zero to 360 min (AUC0-360) of NFP declined in making SSM capsules as compared to control capsules due to a simple physical mixture of NFP and cornstarch, but the values of mean residence time (MRT0-360) extended and abidingness of SSM capsules were admitted with dose-dependent manner. As for a PD parameter, the mean arterial blood pressure (mABP) derived from the SSM capsules showed 15~20% decrease of baseline within 120min after intraduodenal administration, and thereafter the mABP in 2.5 mg SSM capsule was gradually recovered, while a relatively smooth and even change was found in the mABP at 5.0 mg SSM capsule. The relationships between plasma NFP concentration and sampling-time corresponding mABP after intraduodenal administration of SSM capsules showed no rapid change in the mABP, indicating that a sustained-release mechanism due to the SSM functions sufficiently to avoid a fluctuating blood pressure accompanied by going up and down of plasma levels of NFP. The SSM capsules exhibited a sustained-release pharmacokinetics of NFP, and made the fluctuation range with blood pressure small compared to the physical mixture preparations. Thus, it was evidenced that the SSM capsule is useful device to provide a sustained-release systems and optimal therapeutic efficacy of drugs.Keywords: Controlled-release, Cornstarch, Matrix, Nifedipine, Pharmacokinetics, Pharmacodynamics

Enhanced interleukin-10 signaling with 14-member macrolides in lipopolysaccharide-stimulated macrophages

Immunomodulatory effects of 14-member macrolides, namely erythromycin (EM) and clarithromycin (CAM), have been reported in chronic respiratory infectious diseases. It has been suggested that 14-member macrolides have immunomodulatory effects on various lung cells such as alveolar macrophages. Interleukin (IL)-10 is an immunomodulatory cytokine that performs an irreplaceable role in negatively regulating inflammation, primarily via a mechanism that selectively blocks the expression of pro-inflammatory genes. It activates sig-nal transducer and activator of transcription (STAT)-3, and subsequently induces the suppres-sor of cytokine signaling-3 (SOCS-3), resulting in the resolution of inflammatory response in macrophages. However, it has been still unclear whether 14-member macrolides exert immu-nomodulatory effects via IL-10 signaling pathway. We aimed to evaluate whether 14-member macrolides affect the IL-10 signaling pathway. The RAW264.7 macrophage cell line was pre-treated with EM or CAM, and stimulated with lipopolysaccharide (LPS). The levels of IL-10, IL-10 receptor, phosphorylated (p) STAT-3, and SOCS-3 were determined by RT-PCR, ELISA and immunoblotting. We observed increased levels of IL-10, p-STAT-3 and SOCS-3 in the treated cells. In addition, while the levels of tumor necrosis factor-α 6 h after LPS stimulation was equal between vehicle-treated and CAM-treated macrophage cells, those of CAM-treated cells were repressed 36 h following LPS stimulation, compared with those of the control cells. Therefore, the 14-member macrolides may initiate an early resolution of inflammation, in part, via the enhancement of the IL-10/STAT-3/SOCS-3 pathway

Multivesicular Body Formation Requires OSBP–Related Proteins and Cholesterol

In eukaryotes, different subcellular organelles have distinct cholesterol concentrations, which is thought to be critical for biological functions. Oxysterol-binding protein-related proteins (ORPs) have been assumed to mediate nonvesicular cholesterol trafficking in cells; however, their in vivo functions and therefore the biological significance of cholesterol in each organelle are not fully understood. Here, by generating deletion mutants of ORPs in Caenorhabditis elegans, we show that ORPs are required for the formation and function of multivesicular bodies (MVBs). In an RNAi enhancer screen using obr quadruple mutants (obr-1; -2; -3; -4), we found that MVB–related genes show strong genetic interactions with the obr genes. In obr quadruple mutants, late endosomes/lysosomes are enlarged and membrane protein degradation is retarded, although endocytosed soluble proteins are normally delivered to lysosomes and degraded. We also found that the cholesterol content of late endosomes/lysosomes is reduced in the mutants. In wild-type worms, cholesterol restriction induces the formation of enlarged late endosomes/lysosomes, as observed in obr quadruple mutants, and increases embryonic lethality upon knockdown of MVB–related genes. Finally, we show that knockdown of ORP1L, a mammalian ORP family member, induces the formation of enlarged MVBs in HeLa cells. Our in vivo findings suggest that the proper cholesterol level of late endosomes/lysosomes generated by ORPs is required for normal MVB formation and MVB–mediated membrane protein degradation

Targeting of MAPK-associated molecules identifies SON as a prime target to attenuate the proliferation and tumorigenicity of pancreatic cancer cells

Abstract Background Pancreatic cancer is characterized by constitutive activation of mitogen-activated protein kinase (MAPK). Activation of MAPK is associated with the upregulation of genes implicated in the proliferation and survival of pancreatic cancer cells. We hypothesized that knockdown of these MAPK-associated molecules could produce notable anticancer phenotypes. Methods A RNA interference-mediated knockdown screening of 78 MAPK-associated molecules previously identified was performed to find molecules specifically associated with proliferation of pancreatic cancer cells in vitro. Expression of an identified molecule in pancreatic cancer tissues was examined by immunohistochemistry. In vivo tumorigenicity of cancer cells with stable knockdown of the molecule was assayed by using xenograft models. Flow cytometry and live cell imaging were employed to assess an association of the molecule with cell cycle. Results The knockdown screening revealed that knockdown of SON, the gene encoding SON, which is a large serine/arginine-rich protein involved in RNA processing, substantially suppressed pancreatic cancer cell proliferation and survival in vitro and tumorigenicity in vivo. SON expression was higher in ductal adenocarcinomas than in cells of normal ducts and precursor lesions in pancreatic cancer tissues. Knockdown of SON induced G2/M arrest and apoptosis in cultured cancer cells. The suppressive effect of SON knockdown on proliferation was less pronounced in cultured normal duct epithelial cells. SON formed nuclear speckles in the interphase of the cell cycle and dispersed in the cytoplasm during mitosis. Live cell imaging showed that SON diffusely dispersed in the early mitotic phase, accumulated in some foci in the cytoplasm in the late mitotic phase, and gradually reassembled into speckles after mitosis. Conclusion These results indicate that SON plays a critical role in the proliferation, survival, and tumorigenicity of pancreatic cancer cells, suggesting that SON is a novel therapeutic molecular target for pancreatic cancer.</p

Exploring Hidden Atrial Fibrillation in Patients with Type 2 Diabetes Mellitus Admitted to Shinshu University Hospital

Using the event-triggered recorder, SpiderFlash-t AFIB, which allows us to detect asymptomatic or symptomatic arrhythmia, we examined the prevalence of hidden atrial fibrillation (AF) in patients with type 2 diabetes admitted to our hospital. In total, we enrolled 69 patients with type 2 diabetes mellitus admitted to the hospital due to hyperglycemia. Averages of HbA1c, age, duration of the disease, and BMI were 8.9 ％, 64.8 years old, 14.8 years, and 26.0 kg/m2, respectively. Neuropathy, retinopathy, and nephropathy were found in 37 (53.6 ％), 27 (39.1 ％), and 27 (39.1 ％), respectively. Macroangiopathy was found in 13 (18.9 ％). In the first series of surveys where we attached the recorder for 7 days no sustained AF events were found, and only 2 transient events. We attached the recorder for 14 days with 39 subjects in the second series of the survey, and fail to find any AF rhythm. This study is the first attempt to reveal the frequency of hidden AF in diabetes. This finding suggests that screening of atrial fibrillation with SpiderFlash-t AFIB for patients with type 2 diabetic patients hospitalized for glycemic control may not be useful in assessing the prevalence of atrial fibrillation.Article信州医学雑誌 69(2): 75-81(2021)departmental bulletin pape

Tomato root-associated Sphingobium harbors genes for catabolizing toxic steroidal glycoalkaloids

トマト根に定着する細菌からトマトの毒を分解する酵素を発見 --土壌微生物が植物の分泌する有害成分を解毒するメカニズムの理解に貢献--. 京都大学プレスリリース. 2023-10-02.Roots of Bloody Mary. Tomato root-associated Sphingobium harbors genes for neutralizing toxic compound. 京都大学プレスリリース. 2023-10-06.Plant roots exude various organic compounds, including plant specialized metabolites (PSMs), into the rhizosphere. The secreted PSMs enrich specific microbial taxa to shape the rhizosphere microbiome, which is crucial for the healthy growth of the host plants. PSMs often exhibit biological activities; in turn, some microorganisms possess the capability to either resist or detoxify them. Saponins are structurally diverse triterpene-type PSMs that are mainly produced by angiosperms. They are generally considered as plant defense compounds. We have revealed that α-tomatine, a steroid-type saponin secreted from tomato (Solanum lycopersicum) roots, increases the abundance of Sphingobium bacteria. To elucidate the mechanisms underlying the α-tomatine-mediated enrichment of Sphingobium, we isolated Sphingobium spp. from tomato roots and characterized their saponin-catabolizing abilities. We obtained the whole-genome sequence of Sphingobium sp. RC1, which degrades steroid-type saponins but not oleanane-type ones, and performed a gene cluster analysis together with a transcriptome analysis of α-tomatine degradation. The in vitro characterization of candidate genes identified six enzymes that hydrolyzed the different sugar moieties of steroid-type saponins at different positions. In addition, the enzymes involved in the early steps of the degradation of sapogenins (i.e., aglycones of saponins) were identified, suggesting that orthologs of the known bacterial steroid catabolic enzymes can metabolize sapogenins. Furthermore, a comparative genomic analysis revealed that the saponin-degrading enzymes were present exclusively in certain strains of Sphingobium spp., most of which were isolated from tomato roots or α-tomatine-treated soil. Taken together, these results suggest a catabolic pathway for highly bioactive steroid-type saponins in the rhizosphere

Characterization of hemin-binding protein 35 (HBP35) in Porphyromonas gingivalis: its cellular distribution, thioredoxin activity and role in heme utilization

<p>Abstract</p> <p>Background</p> <p>The periodontal pathogen <it>Porphyromonas gingivalis </it>is an obligate anaerobe that requires heme for growth. To understand its heme acquisition mechanism, we focused on a hemin-binding protein (HBP35 protein), possessing one thioredoxin-like motif and a conserved C-terminal domain, which are proposed to be involved in redox regulation and cell surface attachment, respectively.</p> <p>Results</p> <p>We observed that the <it>hbp35 </it>gene was transcribed as a 1.1-kb mRNA with subsequent translation resulting in three proteins with molecular masses of 40, 29 and 27 kDa in the cytoplasm, and one modified form of the 40-kDa protein on the cell surface. A recombinant 40-kDa HBP35 exhibited thioredoxin activity <it>in vitro </it>and mutation of the two putative active site cysteine residues abolished this activity. Both recombinant 40- and 27-kDa proteins had the ability to bind hemin, and growth of an <it>hbp35 </it>deletion mutant was substantially retarded under hemin-depleted conditions compared with growth of the wild type under the same conditions.</p> <p>Conclusion</p> <p><it>P. gingivalis </it>HBP35 exhibits thioredoxin and hemin-binding activities and is essential for growth in hemin-depleted conditions suggesting that the protein plays a significant role in hemin acquisition.</p