Cholangiocarcinoma (CCA) is a malignant biliary tract tumor with a high mortality rate and refractoriness to chemotherapy. Gemcitabine is an anti-cancer chemotherapeutic agent used for CCA, but the ...efficacy of gemcitabine in CCA treatment is limited, due to the acquisition of chemoresistance. The present study evaluated the chemosensitizing effects of Amurensin G (AMG), a natural sirtuin-1 inhibitor derived from
, in the SNU-478 CCA cells. Treatment with AMG decreased the SNU-478 cell viability and the colony formation ability. Annexin V/ Propidium iodide staining showed that the AMG increased apoptotic death. In addition, AMG downregulated anti-apoptotic Bcl-2 expression, while upregulating pro-apoptotic cleaved caspase-3 expression. Treatment with AMG decreased the migratory ability of the cells in a wound healing assay and transwell migration assay. It was observed that AMG decreased the gemcitabine-induced increase in CD44
CD24
CD133
cell populations, and the expression of the Sox-2 protein was decreased by AMG treatment. Co-treatment of AMG with gemcitabine significantly enhanced the production of reactive oxygen species, as observed through mitochondrial superoxide staining, which might be associated with the downregulation of the Sirt1/Nrf2 pathway by AMG. These results indicate that AMG enhances the chemotherapeutic ability of gemcitabine by downregulating cancer stem-like properties in CCA cells. Hence, a combination therapy of AMG with gemcitabine may be an attractive therapeutic strategy for cholangiocarcinoma.
Seaweeds have received considerable attention as sources of dietary fiber and biomass for manufacturing valuable products. The major polysaccharides of red seaweeds include agar and porphyran. In a ...marine environment, marine bacteria utilize agar and porphyran through the agarase and porphyranase genes encoded in their genomes. Most of these enzymes identified and characterized so far originate from marine bacteria. Recently,
Bacteroides plebeius
, a human gut bacterium isolated from seaweed-eating Japanese individuals, was revealed to contain a polysaccharide utilization locus (PUL) targeting the porphyran and agarose of red seaweeds. For example,
B. plebeius
contains an endo-type β-agarase,
Bp
GH16A, belonging to glycoside hydrolase family 16.
Bp
GH16A cleaves the β-1,4-glycosidic linkages of agarose and produces neoagarooligosccharides from agarose. Since it is crucial to study the characteristics of
Bp
GH16A to understand the depolymerization pathway of red seaweed polysaccharides by
B. plebeius
in the human gut and to industrially apply the enzyme for the depolymerization of agar, we characterized
Bp
GH16A for the first time. According to our results,
Bp
GH16A is an extracellular endo-type β-agarase with an optimal temperature of 40 °C and an optimal pH of 7.0, which correspond to the temperature and pH of the human colon.
Bp
GH16A depolymerizes agarose into neoagarotetraose (as the main product) and neoagarobiose (as the minor product). Thus,
Bp
GH16A is suggested to be an important enzyme that initiates the depolymerization of red seaweed agarose or agar in the human gut by
B. plebeius
.
Key points
•
Bacteroides plebeius is a human gut bacterium isolated from seaweed-eating humans.
•
BpGH16A is an extracellular endo-type β-agarase with optimal conditions of 40 °C and pH 7.0.
•
BpGH16A depolymerizes agarose into neoagarotetraose and neoagarobiose.
Abstract
Various health beneficial outcomes associated with red seaweeds, especially their polysaccharides, have been claimed, but the molecular pathway of how red seaweed polysaccharides are ...degraded and utilized by cooperative actions of human gut bacteria has not been elucidated. Here, we investigated the enzymatic and metabolic cooperation between two human gut symbionts,
Bacteroides plebeius
and
Bifidobacterium longum
ssp
. infantis
, with regard to the degradation of agarose, the main carbohydrate of red seaweed. More specifically,
B. plebeius
initially decomposed agarose into agarotriose by the actions of the enzymes belonging to glycoside hydrolase (GH) families 16 and 117 (i.e.,
Bp
GH16A and
Bp
GH117) located in the polysaccharide utilization locus, a specific gene cluster for red seaweed carbohydrates. Then,
B. infantis
extracted energy from agarotriose by the actions of two agarolytic β-galactosidases (i.e., Bga42A and Bga2A) and produced neoagarobiose.
B. plebeius
ultimately acted on neoagarobiose by
Bp
GH117, resulting in the production of 3,6-anhydro-
l
-galactose, a monomeric sugar possessing anti-inflammatory activity
.
Our discovery of the cooperative actions of the two human gut symbionts on agarose degradation and the identification of the related enzyme genes and metabolic intermediates generated during the metabolic processes provide a molecular basis for agarose degradation by gut bacteria.
Oxygen-independent, flavin-binding fluorescent proteins (FbFPs) are emerging as alternatives to green fluorescent protein (GFP), which has limited applicability in studying anaerobic microorganisms, ...such as human gastrointestinal bacteria, which grow in oxygen-deficient environments. However, the utility of these FbFPs has been compromised because of their poor fluorescence emission. To overcome this limitation, we have employed a high-throughput library screening strategy and engineered an FbFP derived from
(SB2) for enhanced quantum yield. Of the resulting SB2 variants, KOFP-7 exhibited a significantly improved quantum yield (0.61) compared to other reported engineered FbFPs, which was even higher than that of enhanced GFP (EGFP, 0.60), with significantly enhanced tolerance against a strong reducing agent.
Chromosome 9 open reading frame 72 (
) gene pathogenic variants have been typically associated with frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), but recent studies suggest ...their involvement in other disorders. This report describes a family with an autosomal dominant pattern of inheritance of progressive verbal auditory agnosia due to GGGGCC repeat expansion in C9orf72. A 60-year-old right-handed male truck driver presented with slowly progressive poor speech perception for 8 years, which became most troublesome when receiving verbal orders over the phone. He had difficulty recognizing single-syllable spoken words beyond his hearing loss but had no problem understanding complex written language. He had a heterozygous pathogenic variant carrying 160 hexanucleotide repeats in the C9orf72 gene. His family history included his deceased mother with similar symptoms that had progressed over 30 years, as well as his older brother and youngest sister who experienced speech perception difficulty beginning in their early fifties. His asymptomatic younger brother had a heterozygous 2 repeat in the C9orf72 gene, while his symptomatic youngest sister had a heterozygous 159 repeat. The patient and his sister exhibited more pronounced cortical thinning in the frontotemporoparietal areas. The discrepancy observed between the distribution of atrophy and the presentation of symptoms in patients with C9orf72 pathogenic repeat expansion may be attributable to the slow progression of their clinical course over time. The variable symptom presentation of C9orf72 pathogenic repeat expansion highlights the importance of considering this pathogenic variant as a potential cause of autosomal dominant degenerative brain diseases beyond FTD and ALS.
To investigate the topographic changes of white matter (WM) integrity and cortical thickness related to gait disturbances and determine whether these neural correlates mediate the association between ...cerebral small vessel disease (CSVD) and gait disturbances.
A total of 129 patients with subcortical vascular cognitive impairment were included. CSVD severity was quantified as global and regional WM hyperintensities (WMH) volume and lacune and microbleed numbers. Amyloid burdens were assessed using Pittsburgh compound B (PiB)-PET scanning. Gait score was measured using a standardized scale. WM integrity was assessed by applying tract-based spatial statistics. Cortical thickness was measured using surface-based methods. Path analysis for gait score was performed using regional CSVD markers as predictors and fractional anisotropy (FA) and cortical thickness as mediators.
Periventricular WMH (PWMH) volume was associated with gait score, regardless of other CSVD. PiB retention ratio was not associated with gait score. Gait score was correlated with FA in the frontal and parietal WM and bilateral corpus callosum and with cortical thinning in the bilateral frontal and lateral temporo-parieto-occipital regions. Path analysis for gait score showed that PWMH contributed to gait disturbances with the mediation of mean FA or cortical thickness.
Our findings suggest that WMH-related cortical thinning as well as disrupted integrity of periventricular WM is linked to gait disturbances.
Cordycepin, a valuable bioactive component isolated from
, has been reported to possess anti-cancer potential and the property to enhance the effects of chemotherapeutic agents in various types of ...cancers. However, the ability of cordycepin to chemosensitize cholangiocarcinoma (CCA) cells to gemcitabine has not yet been evaluated. The current study was performed to evaluate the above, and the mechanisms associated with it. The study analyzed the effects of cordycepin in combination with gemcitabine on the cancer stem-like properties of the CCA SNU478 cell line, including its anti-apoptotic, migratory, and antioxidant effects. In addition, the combination of cordycepin and gemcitabine was evaluated in the CCA xenograft model. The cordycepin treatment significantly decreased SNU478 cell viability and, in combination with gemcitabine, additively reduced cell viability. The cordycepin and gemcitabine co-treatment significantly increased the Annexin V+ population and downregulated B-cell lymphoma 2 (Bcl-2) expression, suggesting that the decreased cell viability in the cordycepin+gemcitabine group may result from an increase in apoptotic death. In addition, the cordycepin and gemcitabine co-treatment significantly reduced the migratory ability of SNU478 cells in the wound healing and trans-well migration assays. It was observed that the cordycepin and gemcitabine cotreatment reduced the CD44
CD133
population in SNU478 cells and the expression level of sex determining region Y-box 2 (Sox-2), indicating the downregulation of the cancer stem-like population. Cordycepin also enhanced oxidative damage mediated by gemcitabine in MitoSOX staining associated with the upregulated Kelch like ECH Associated Protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) expression ratio. In the SNU478 xenograft model, co-administration of cordycepin and gemcitabine additively delayed tumor growth. These results indicate that cordycepin potentiates the chemotherapeutic property of gemcitabine against CCA, which results from the downregulation of its cancer-stem-like properties. Hence, the combination therapy of cordycepin and gemcitabine may be a promising therapeutic strategy in the treatment of CCA.
To determine whether amyloid and hypertensive cerebral small vessel disease (hCSVD) changes synergistically affect the progression of lobar microbleeds in patients with subcortical vascular mild ...cognitive impairment (svMCI).
Among 72 patients with svMCI who underwent brain MRI and
C Pittsburgh compound B (PiB)-PET, 52 (72.2%) completed the third year of follow-up. These patients were evaluated by annual neuropsychological testing, brain MRI, and follow-up PiB-PET.
Over 3 years, 31 of 52 patients (59.6%) had incident cerebral microbleeds (CMBs) in the lobar and deep regions. Both baseline and longitudinal changes in lacune numbers were associated with increased numbers of lobar and deep microbleeds, while baseline and longitudinal changes in PiB uptake ratio were associated only with the progression of lobar microbleeds, especially in the temporal, parietal, and occipital areas. Regional white matter hyperintensity severity was also associated with regional lobar CMBs in the parietal and occipital regions. There were interactive effects between baseline and longitudinal lacune number and PiB retention on lobar microbleed progression. Increased lobar, but not deep, CMBs were associated with decreased scores in the digit span backward task and Rey-Osterrieth Complex Figure Test.
Our findings suggest that amyloid-related pathology and hCSVD have synergistic effects on the progression of lobar microbleeds, providing new clinical insight into the interaction between amyloid burden and hCSVD on CMB progression and cognitive decline with implications for developing effective prevention strategies.
To investigate the effect of polygenic load on the progression of striatal dopaminergic dysfunction in patients with Parkinson disease (PD).
Using data from 335 patients with PD in the Parkinson's ...Progression Markers Initiative (PPMI) database, we investigated the longitudinal association of PD-associated polygenic load with changes in striatal dopaminergic activity as measured by
I-N-3-fluoropropyl-2-β-carboxymethoxy-3β-(4-iodophenyl) nortropane (
I-FP-CIT) SPECT over 4 years. PD-associated polygenic load was estimated by calculating weighted genetic risk scores (GRS) using 1) all available 27 PD-risk single nucleotide polymorphisms (SNPs) in the PPMI database (GRS1) and 2) 23 SNPs with minor allele frequency >0.05 (GRS2).
GRS1 and GRS2 were correlated with younger age at onset in patients with PD (GRS1, Spearman ρ = -0.128,
= 0.019; GRS2, Spearman ρ = -0.109,
= 0.047). Although GRS1 did not show an association with changes in striatal
I-FP-CIT availability, GRS2 was associated with a slower decline of striatal dopaminergic activity (interactions with disease duration in linear mixed model; caudate nucleus, estimate = 0.399, SE = 0.165,
= 0.028; putamen, estimate = 0.396, SE = 0.137,
= 0.016).
Our results suggest that genetic factors for PD risk may have heterogeneous effects on striatal dopaminergic degeneration, and some factors may be associated with a slower decline of dopaminergic activity. Composition of PD progression-specific GRS may be useful in predicting disease progression in patients.
Abstract
Context
Ectopic fat deposition in skeletal muscle, termed myosteatosis, is a key factor in developing insulin resistance.
Objective
This work aimed to evaluate the association between ...insulin resistance and myosteatosis in a large Asian population.
Methods
A total of 18 251 participants who had abdominal computed tomography were included in this cross-sectional study. Patients were categorized into 4 groups according to quartiles of Homeostatic Model Assessment for Insulin Resistance (HOMA-IR). The total abdominal muscle area (TAMA) at the L3 vertebral level was segmented into normal-attenuation muscle area (NAMA), low-attenuation muscle area (LAMA), and intermuscular adipose tissue (IMAT). The absolute values of TAMA, NAMA, LAMA, and IMAT and the ratios of NAMA/BMI, LAMA/BMI, and NAMA/TAMA were used as myosteatosis indices.
Results
The absolute values of TAMA, NAMA, LAMA, and IMAT appeared to increase with higher HOMA-IR levels, and LAMA/BMI showed a similar upward trend. Meanwhile, the NAMA/BMI and NAMA/TAMA index showed downward trends. As HOMA-IR levels increased, the odds ratios (ORs) of the highest quartile of NAMA/BMI and NAMA/TAMA index decreased and that of LAMA/BMI increased. Compared with the lowest HOMA-IR group, the adjusted ORs (95% CI) in the highest HOMA-IR group for the lowest NAMA/TAMA quartile were 0.414 (0.364-0.471) in men and 0.464 (0.384-0.562) in women. HOMA-IR showed a negative correlation with NAMA/BMI (r = −0.233 for men and r = −0.265 for women), and NAMA/TAMA index (r = −0.211 for men and r = −0.214 for women), and a positive correlation with LAMA/BMI (r = 0.160 for men and r = 0.119 for women); P was less than .001 for all.
Conclusion
In this study, a higher HOMA-IR level was significantly associated with a high risk of myosteatosis.
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