Pax4-Ghrelin mediates the conversion of pancreatic ɛ-cells to β-cells after extreme β-cell loss in zebrafish

Pancreatic ɛ-cells producing ghrelin are one type of endocrine cell found in islets, which have been shown to influence other intra-islet cells, especially in regulating the function of β cells. However, the role of such cells during β-cell regeneration is heretofore unknown. Here, using a zebrafish nitroreductase (NTR)-mediated β-cells ablation model, we uncover that ghrelin-positive ɛ-cells in the pancreas act as contributors to neogenic β-cells after extreme β-cell loss. Further studies show the overexpression of ghrelin or the expansion of ɛ-cells potentiates β-cell regeneration. Lineage tracing confirms a proportion of embryonic ɛ-cells can transdifferentiate to β-cells, and the deletion of Pax4 enhances this transdifferentiation of ɛ-cells to β-cells. Mechanistically, Pax4 binds to the ghrelin regulatory region and represses its transcription. Thus deletion of Pax4 derepresses ghrelin expression and causes producing more ghrelin-positive cells, enhancing the transdifferentiation of ɛ-cells to β-cells and consequent potentiating β-cells regeneration. Our findings reveal a novel role of ɛ-cells during zebrafish β-cell regeneration, indicating Pax4 regulates ghrelin transcription and mediates the conversion of embryonic ɛ-cells to β-cells after extreme β-cell loss.

[A family study of the compound heterozygous mutation of the UGT1A1 gene causing Crigler-Najjar syndrome type II]

Objective: To investigate the family gene features in Crigler-Najjar syndrome (CNS) type II. Methods: The UGT1A1 gene and related bilirubin metabolism genes were comprehensively analysed in a CNS-II family (3 CNS-II, 1 Gilbert syndrome, and 8 normal subjects). The genetics basis of CNS-II were investigated from the perspective of family analysis. Results: In three cases, compound heterozygous mutations at three sites of the UGT1A1 gene (c.-3279T > G, c.211G > A and c.1456T > G) caused CNS-II. Gilbert syndrome and CNS-II were not significantly associated with distribution or diversity loci. Conclusion: The compound heterozygous pathogenic mutations (c.-3279T > G, c.211G > A, and c.1456T > G) at three loci of the UGT1A1 gene may be the feature of the newly discovered CNS-II family genes based on the CNS-II family study.

[Observation on the clinical outcomes of continued pregnancy following cesarean scar pregnancy in 55 women]

Objective: To observe the clinical outcomes of continued pregnancy in pregnant women with cesarean scar pregnancy (CSP). Methods: A retrospective analysis was performed on the pregnancy outcomes of 55 pregnant women who were diagnosed with CSP at the Second Affiliated Hospital of Army Medical University during the first trimester of pregnancy from August 1st, 2018 to October 31st, 2021 and strongly requested to continue the pregnancy. Results: Of the 55 pregnant women, 15 terminated the pregnancy in the first trimester, 1 underwent hysterotomy at 23 weeks of gestation due to cervical dilation, and 39 (71%, 39/55) continued pregnancy to the third trimester achieving live births via cesarean section. The gestational age of the 39 pregnant women delivered by cesarean section was 35⁺⁶ weeks (range: 28⁺⁵-39⁺² weeks), of whom 7 cases at 28⁺⁵-33⁺⁶ weeks, 20 cases at 34-36⁺⁶ weeks, and 12 cases at 37-39⁺² weeks. The results of pathological examination were normal placenta in 3 cases (8%, 3/39), placenta creta in 4 cases (10%, 4/39), placenta increta in 9 cases (23%, 9/39) and placenta percreta in 23 cases (59%, 23/39). Among the 36 pregnant women who were pathologically confirmed as placenta accreta spectrum disorders (PAS) after surgery, the last prenatal ultrasonography showed placenta previa in 27 cases (75%, 27/36) and not observed placenta previa in 9 cases. The median intraoperative blood loss, autologous blood transfusion, and allogeneic suspended red blood cell infusion of 39 pregnant women during cesarean section were 1 000 ml (300-3 500 ml), 300 ml (0-2 000 ml) and 400 ml (0-2 400 ml), respectively. The uterine preservation rate was 100% (39/39), and only 1 case received cystostomy due to intracystic hemorrhage. The birth weight of the newborn was 2 580 g (1 350-3 800 g), and 1 case of mild asphyxia. Conclusions: Pregnant women with CSP who continue pregnancy under close monitoring after adequate ultrasound evaluation and doctor-patient communication could achieve better maternal and infant outcomes, but pregnant women with CSP are highly likely to continue pregnancy and develop into PAS. Effective hemostasis means and multidisciplinary team cooperation are needed in perinatal period for ensuring maternal and fetal safety.

Alterations in immune cell heterogeneities in the brain of aged zebrafish using single-cell resolution

Immunocytes, including the microglia, are crucial in the neurodegenerative process in old people. However, the understanding of regarding microglia heterogeneity and other involved immunocytes remains elusive. We analyzed 26,456 immunocytes from 12-and 26-month-old zebrafish brains at single-cell resolution. Microglia and T lymphocytes were detected in the brain at both time points. Two types of microglia were annotated, namely, ac⁺ microglia and xr⁺ microglia, which were clustered into subsets 1, 2, 3, 4, 5, and subsets 6, 7, 8, 9, respectively. Diversified microglia predominated the adult brains and cooperated with T cells to perform the functions of immune response and neuronal nutrition. We validated the specific microglia markers. The novel transgenic lines, Tg(lgals3bpb:eGFP) and Tg(apoc1:eGFP), were created, which faithfully labeled ac⁺ microglia and served as valuable labeling tools. However, the microglia population reduced while T cells of six subtypes intriguingly increased to serve as the primary immune cells in aged brains. Unlike in 12-month-old brains, T cells, together with microglia, exhibited a coordinated signature of inflammation in the 26-month-old brains. Our findings revealed the immunocytes atlas in aged zebrafish brains. It implied the involvement of microglia and T cells in the progression of neurodegeneration in aging.

Functional screening of congenital heart disease risk loci identifies 5 genes essential for heart development in zebrafish

Congenital heart disease (CHD) is the most common birth defect worldwide and a main cause of perinatal and infant mortality. Our previous genome-wide association study identified 53 SNPs that associated with CHD in the Han Chinese population. Here, we performed functional screening of 27 orthologous genes in zebrafish using injection of antisense morpholino oligos. From this screen, 5 genes were identified as essential for heart development, including iqgap2, ptprt, ptpn22, tbck and maml3. Presumptive roles of the novel CHD-related genes include heart chamber formation (iqgap2 and ptprt) and atrioventricular canal formation (ptpn22 and tbck). While deficiency of maml3 led to defective cardiac trabeculation and consequent heart failure in zebrafish embryos. Furthermore, we found that maml3 mutants showed decreased cardiomyocyte proliferation which caused a reduction in cardiac trabeculae due to inhibition of Notch signaling. Together, our study identifies 5 novel CHD-related genes that are essential for heart development in zebrafish and first demonstrates that maml3 is required for Notch signaling in vivo.

[Epidemiological characteristics of two local COVID-19 outbreaks caused by 2019-nCoV Omicron variant in Guangzhou, China]

Objective: To understand the epidemiological characteristics of two local COVID-19 outbreaks caused by 2019-nCoV Omicron variant in Guangzhou, such as incubation period, serial interval, basic reproductive number (R₀) and the influence of gathering places on R₀, and provide evidence for the prevention and control of Omicron variant infection. Methods: The data of daily confirmed cases of Omicron variant infection from April 8 to May 8, 2022 in two COVID-19 outbreaks in Guangzhou were collected for model fitting. Weibull, Gamma and lognormal distribution were used to estimate incubation period and serial interval. Exponential growth method and the maximum likelihood estimation were used to estimate R₀. Results: The median of incubation period was 2.94 (95%CI: 2.52-3.38) days and median of serial interval was 3.32 (95%CI: 2.89-3.81) days. The estimated R₀ in small-size place was 4.40 (95%CI: 3.95-4.85), while the estimated R₀ at airport was 11.35 (95%CI: 11.02-11.67). Conclusion: The incubation period of Omicron variant in two local COVID-19 outbreaks in Guangzhou is significantly shorter than that of delta variant. The higher the gathering degree in a place, the larger the R₀. Due to its rapid transmission, COVID-19 epidemic is prone to occur. Therefore, the COVID-19 prevention and control strategy should be dynamically adjusted in time.

[Discussion on relevant issues of Technical Specifications for Occupational Health Surveillance (GBZ 188-2014)]

Technical Specifications for Occupational Health Surveillance (GBZ 188-2014) is an important basis for judging suspected occupational diseases and occupational contraindications. There are crossing over or overlap between occupational contraindications and diagnostic criteria of poisoning damage. Occupational contraindications have different meanings with the degree and range of common diseases or symptoms and the frequency of physical examination during employment conflicts with the current standard. Based on the practice of occupational health examination in a large population, the present study analyzed relevant articles and put forward some suggestions for revision, in combination with clinical medicine, occupational health standards, and diagnostic standards of occupational diseases. The modification could provide a reference for the revision of Technical Specifications for Occupational Health Surveillance and the practice of occupational health examination.

Nrf2 dictates the neuronal survival and differentiation of embryonic zebrafish harboring compromised alanyl-tRNA synthetase

tRNA synthetase deficiency leads to unfolded protein responses in neuronal disorders; however, its function in embryonic neurogenesis remains unclear. This study identified an aars1cq71/cq71 mutant zebrafish allele that showed increased neuronal apoptosis and compromised neurogenesis. aars1 transcripts were highly expressed in primary neural progenitor cells, and their aberration resulted in protein overloading and activated Perk. nfe2l2b, a paralog of mammalian Nfe2l2, which encodes Nrf2, is a pivotal executor of Perk signaling that regulates neuronal phenotypes in aars1cq71/cq71 mutants. Interference of nfe2l2b in nfe2l2bΔ1/Δ1 mutants did not affect global larval development. However, aars1cq71/cq71;nfe2l2bΔ1/Δ1 mutant embryos exhibited increased neuronal cell survival and neurogenesis compared with their aars1cq71/cq71 siblings. nfe2l2b was harnessed by Perk at two levels. Its transcript was regulated by Chop, an implementer of Perk. It was also phosphorylated by Perk. Both pathways synergistically assured the nuclear functions of nfe2l2b to control cell survival by targeting p53. Our study extends the understanding of tRNA synthetase in neurogenesis and implies that Nrf2 is a cue to mitigate neurodegenerative pathogenesis.

[Xenon post-conditioning protects against spinal cord ischemia-reperfusion injury in rats by downregulating mTOR pathway and inhibiting endoplasmic reticulum stress-induced neuronal apoptosis]

OBJECTIVE

The purpose of this study was to determine whether xenon post-conditioning affects mTOR signaling as well as endoplasmic reticulum stress (ERS)-apoptosis pathway in rats with spinal cord ischemia/reperfusion injury.

METHODS

Fifty male rats were randomized equally into sham-operated group (Sham group), I/R model group (I/R group), I/R model+ xenon post-conditioning group (Xe group), I/R model+rapamycin (a mTOR signaling pathway inhibitor) treatment group (I/R+ Rapa group), and I/R model + xenon post- conditioning with rapamycin treatment group (Xe + Rapa group).. In the latter 4 groups, SCIRI was induced by clamping the abdominal aorta for 85 min followed by reperfusion for 4 h. Rapamycin (or vehicle) was administered by daily intraperitoneal injection (4 mg/kg) for 3 days before SCIRI, and xenon post-conditioning by inhalation of 1∶1 mixture of xenon and oxygen for 1 h at 1 h after initiation of reperfusion; the rats without xenon post-conditioning were given inhalation of nitrogen and oxygen (1∶ 1). After the reperfusion, motor function and histopathologic changes in the rats were examined. Western blotting and real-time PCR were used to detect the protein and mRNA expressions of GRP78, ATF6, IRE1α, PERK, mTOR, p-mTOR, Bax, Bcl-2 and caspase-3 in the spinal cord.

RESULTS

The rats showed significantly lowered hind limb motor function following SCIRI (P < 0.01) with a decreased count of normal neurons, increased mRNA and protein expressions of GRP78, ATF6, IRE1α, PERK, and caspase-3, and elevated p-mTOR/mTOR ratio and Bax/Bcl-2 ratio (P < 0.01). Xenon post-conditioning significantly decreased the mRNA and protein levels of GRP78, ATF6, IRE1α, PERK and caspase-3 (P < 0.05 or 0.01) and reduced p-mTOR/mTOR and Bax/Bcl-2 ratios (P < 0.01) in rats with SCIRI; the mRNA contents and protein levels of GRP78 and ATF6 were significantly decreased in I/R+Rapa group (P < 0.01). Compared with those in Xe group, the rats in I/R+Rapa group and Xe+Rapa had significantly lowered BBB and Tarlov scores of the hind legs (P < 0.01), and caspase-3 protein level and Bax/Bcl-2 ratio were significantly lowered in Xe+Rapa group (P < 0.05 or 0.01).

CONCLUSION

By inhibiting ERS and neuronal apoptosis, xenon post- conditioning may have protective effects against SCIRI in rats. The mTOR signaling pathway is partially involved in this process.

Brain vascular damage-induced lymphatic ingrowth is directed by Cxcl12b/Cxcr4a

After ischemic stroke, promotion of vascular regeneration without causing uncontrolled vessel growth appears to be the major challenge for pro-angiogenic therapies. The molecular mechanisms underlying how nascent blood vessels (BVs) are correctly guided into the post-ischemic infarction area remain unknown. Here, using a zebrafish cerebrovascular injury model, we show that chemokine signaling provides crucial guidance cues to determine the growing direction of ingrown lymphatic vessels (iLVs) and, in turn, that of nascent BVs. The chemokine receptor Cxcr4a is transcriptionally activated in the iLVs after injury, whereas its ligand Cxcl12b is expressed in the residual central BVs, the destinations of iLV ingrowth. Mutant and mosaic studies indicate that Cxcl12b/Cxcr4a-mediated chemotaxis is necessary and sufficient to determine the growing direction of iLVs and nascent BVs. This study provides a molecular basis for how the vessel directionality of cerebrovascular regeneration is properly determined, suggesting potential application of Cxcl12b/Cxcr4a in the development of post-ischemic pro-angiogenic therapies.

Sulfamethoxazole induces brain capillaries toxicity in zebrafish by up-regulation of VEGF and chemokine signalling

Sulfamethoxazole (SMX) is a widespread broad-spectrum bacteriostatic antibiotic. Its residual is frequently detected in the water and may therefore bioaccumulate in the brain of aquatic organisms via blood circulation. Brain capillaries toxicity is very important for brain development. However, little information is available in the literature to show the toxicity of SMX to brain development. To study the SMX's brain toxic effects and the related mechanisms, we exposed zebrafish embryos to SMX at different concentrations (0 ppm, 1 ppm, 25 ppm, 100 ppm and 250 ppm) and found that high concentration (250 ppm) of SMX would not only caused an abnormal in malformation rate, hatching rate, body length and survival rate of zebrafish embryos, but also lead to brain oedema. In addition, SMX also induced cerebral ischaemia, aggravates oxidative stress, and changes genes related to oxidative stress (sod1, cat, gpx4, and nrf2). Furthermore, ischaemia caused by SMX could promote ectopic angiogenesis in brain via activating the angiogenesis-related genes (vegfab, cxcr4a, cxcl12b) from 24 h to 53 h. Inhibition of VEGF signalling by SU5416, or inhibition of chemokine downstream PI3K signalling by LY294002, could rescue the brain capillaries toxicity and brain oedema induced by SMX. Our results provide new evidence for the brain toxicity of SMX and its residual danger in the environment and aquatic organisms.

Altered dynamic functional topology in first-episode untreated patients with schizophrenia can aid in early diagnosis

Introduction

There is a growing consensus on brain networks that it is not immutable but rather a dynamic complex system for adapting environment. The neuroimaging research studying how brain regions work collaboratively with dynamic methods had demonstrated its effectiveness in revealing the neural mechanisms of schizophrenia.

Objectives

To investigate altered dynamic brain functional topology in first-episode untreated schizophrenia patients (SZs) and establish classification models to find objective brain imaging biomarkers.

Methods

Resting-state-functional magnetic resonance data for SZs and matched healthy controls were obtained(Table1).

Power-264-template was used to extract nodes and sliding-window approach was carried out to establish functional connectivity matrices. Functional topology was assessed by eigenvector centrality(EC) and node efficiency and its time-fluctuating was evaluated with coefficient of variation(CV). Group differences of dynamic topology and correlation analysis between Positive and Negative Syndrome Scale(PANSS) scores and topology indices showing group differences, which also were used in establishing classification models, was examed.

Results

The CV of node efficiency in angular and paracingulate gyrus was larger in SZs. There are 13 nodes assigned into several brain networks displaying altered CV of EC between groups(Figure1.A). Fluctuation of EC of the node in DMN, which was lower in SZs, showed negative correlation with PANSS total scores(Figure1.B). Dynamic functional topology of above nodes was used to train classification models and demonstrated 80% and 71% accuracy for support vector classification(SVC) and random forest(RF), respectively(Figure2).

Conclusions

Dynamic functional topology illustrated a capability in identifying SZs. Aberrated dynamics of DMN relevant to severity of patient’s symptoms could reveal the reason why it contributed to classification.

Disclosure

No significant relationships.

Brain controllability and clinical relevance in schizophrenia

Introduction

Apart from the psychiatric symptoms, cognitive deficits are also the core symptoms of schizophrenia. Brain network control theory provided information on the role of a specific brain region in the cognitive control process, helping understand the neural mechanism of cognitive impairment in schizophrenia.

Objectives

To characterize the control properties of functional brain network in first-episode untreated patients with schizophrenia and the relationships between controllability and psychiatric symptoms, as well as exploring the predictive value of controllability in differentiating patients from healthy controls (HCs).

Methods

Average and modal controllability of brain networks were calculated and compared between 133 first-episode untreated patients with schizophrenia and 135 HCs. The associations between controllability and clinical symptoms were evaluated using sparse canonical correlation analysis. Support vector machine (SVM) and SVM-recursive feature elimination combined with the controllability were performed to establish the individual prediction model.

Results

Compared to HCs, the patients with schizophrenia showed increased average controllability and decreased modal controllability in dorsal anterior cingulate cortex (dACC). Brain controllability predominantly in somatomotor, default mode, and visual networks was associated with the positive symptomatology of schizophrenia. The established model could identify patients with an accuracy of 0.68. Furthermore, the most discriminative features were located in dACC, medial prefrontal lobe, precuneus and superior temporal gyrus.

Conclusions

Altered controllability in dACC may play a critical role in the neuropathological mechanisms of cognitive deficit in schizophrenia, which could drive the brain function to different states to cope with varied cognitive tasks. As symptom-related biomarkers, controllability could be also beneficial to individual prediction in schizophrenia.

Disclosure

No significant relationships.

[Comparison of the long-term outcomes of focused ultrasound ablation surgery for uterine fibroids and myomectomy]

Objective: To compare the long-term outcomes after focused ultrasound ablation surgery (FUAS) versus myomectomy for uterine fibroids. Methods: A retrospective study was conducted on women who were treated by FUAS or myomectomy for uterine fibroids at First Medical Center of Chinese PLA General Hospital from January 2007 to January 2015. Regular follow-up was conducted to evaluate the symptoms relief, symptoms recurrence, the need for re-interventions and complications of the two groups. Results: The effective rates were 95.7% (730/763) and 95.5% (1 151/1 205) in women who were treated by FUAS and myomectomy, no statistical difference was seen between the two groups (χ²=0.027, P=0.869). The cumulative rates of symptoms recurrence at 1 year, 3 years, 5 years, 8 years and 10 years of follow-up in FUAS group were 1.8%, 6.8%, 11.9%, 15.2% and 15.9%, respectively; and the cumulative re-intervention rates were 0.7%, 4.1%, 6.8%, 9.9% and 11.0%, respectively. The cumulative rates of symptoms recurrence at 1 year, 3 years, 5 years, 8 years and 10 years of follow-up in myomectomy group were 1.8%, 5.9%, 10.6%, 14.2% and 14.9%, respectively; and the cumulative re-intervention rates were 0.9%, 4.5%, 7.8%, 10.3% and 11.4%, respectively. No statistical differences were seen between the two groups (all P>0.05). There were no significant differences in the effective rate, symptoms recurrence rate and re-intervention rate between the two groups in patients with intermural fibroids; but the effective rate of FUAS (95.9%, 235/245) was higher than that of myomectomy (89.1%, 115/129), the symptoms recurrence rate (11.9%, 28/235) was lower than that of myomectomy (27.8%, 32/115), and the re-intervention rate (7.7%, 18/235) was lower than that of myomectomy (17.4%, 20/115) in patients with submucosal fibroids, there were significant different (all P<0.05). The effective rate of FUAS (91.0%, 132/145) was lower than that of myomectomy (97.0%, 322/332), the symptoms recurrence rate (32.6%, 43/132) was higher than that of myomectomy (9.9%, 32/322), and the re-intervention rate (22.0%, 29/132) was higher than that of myomectomy group (6.2%, 20/132) in patients with subserosal fibroids, there were significant different (all P<0.01). The incidences of total [1.8% (14/763) vs 21.9% (264/1 205)], minor and moderate adverse events were lower in FUAS group than myomectomy group (all P<0.001). Conclusion: Satisfaction with long-term outcomes after FUAS treatment or myomectomy for uterine fibroids is comparable.

SP1-induced lncRNA DUBR promotes stemness and oxaliplatin resistance of hepatocellular carcinoma via E2F1-CIP2A feedback

Oxaliplatin-based chemotherapy is widely used to treat advanced hepatocellular carcinoma (HCC), but many patients develop drug resistance that leads to tumor recurrence. Cancer stem cells (CSCs) are known to contribute to chemoresistance, the underlying mechanism, however, remains largely unknown. In this study, we discovered a specificity protein 1 (SP1)-induced long noncoding RNA--DPPA2 upstream binding RNA (DUBR) and its high expression in HCC tissues and liver CSCs. DUBR was associated with HCC progression and poor chemotherapy response. Moreover, DUBR facilitated the stemness and oxaliplatin resistance of HCC in vitro and in vivo. Mechanistically, DUBR upregulated cancerous inhibitor of protein phosphatase 2A (CIP2A) expression through E2F1-mediated transcription regulation. DUBR also exerted function by binding microRNA (miR)-520d-5p as a competing endogenous RNA to upregulate CIP2A at mRNA level. CIP2A, in turn, stabilized E2F1 protein and activated the Notch1 signaling pathway, thereby increasing the stemness feature of HCC and leading to chemoresistance. In conclusion, we identified SP1/DUBR/E2F1-CIP2A as a critical axis to activate the Notch1 signaling pathway and promote stemness and chemoresistance of HCC. Therefore, DUBR could be a potential target in HCC treatment.

Formimidoyltransferase cyclodeaminase prevents the starvation-induced liver hepatomegaly and dysfunction through downregulating mTORC1

The liver is a crucial center in the regulation of energy homeostasis under starvation. Although downregulation of mammalian target of rapamycin complex 1 (mTORC1) has been reported to play pivotal roles in the starvation responses, the underpinning mechanisms in particular upstream factors that downregulate mTORC1 remain largely unknown. To identify genetic variants that cause liver energy disorders during starvation, we conduct a zebrafish forward genetic screen. We identify a liver hulk (lvh) mutant with normal liver under feeding, but exhibiting liver hypertrophy under fasting. The hepatomegaly in lvh is caused by enlarged hepatocyte size and leads to liver dysfunction as well as limited tolerance to starvation. Positional cloning reveals that lvh phenotypes are caused by mutation in the ftcd gene, which encodes the formimidoyltransferase cyclodeaminase (FTCD). Further studies show that in response to starvation, the phosphorylated ribosomal S6 protein (p-RS6), a downstream effector of mTORC1, becomes downregulated in the wild-type liver, but remains at high level in lvh. Inhibition of mTORC1 by rapamycin rescues the hepatomegaly and liver dysfunction of lvh. Thus, we characterize the roles of FTCD in starvation response, which acts as an important upstream factor to downregulate mTORC1, thus preventing liver hypertrophy and dysfunction.

Under starvation, the liver initiates a series of metabolic adaptations to maintain energy homeostasis that is critical for survival. During this process, mTORC1 pathway is downregulated to reduce anabolism and promote catabolism, ensuring adequate usage of limited resources. However, mechanisms underlying the downregulation of mTORC1 remain incompletely understood. In a zebrafish genetic screen aiming to characterize factors important for starvation response in the liver, we identify an ftcd mutation that causes liver hypertrophy and dysfunction under fasting. FTCD acts upstream to inactivate mTORC1 in response to starvation. Our work reveals previously unappreciated roles of FTCD in the responses to energy stress through modulating mTORC1 activities, moreover implicates a potential liver disorder risk of FTCD deficiency under the circumstances of starvation.

[Clinical and immunological characteristics of 88 cases of overlap myositis]

OBJECTIVE

To investigate the clinical and immunological characteristics of overlap myositis (OM) patients.

METHODS

The data of 368 patients with idiopathic inflammatory myopathies (IIMs) admitted to Peking University People's Hospital from January 2004 to August 2020 were analyzed retrospectively, including demographic characteristics, clinical characteristics (including fever, Gottron' s sign/papules, Heliotrope rash, V-sign, Shawl sign, Mechanic' s hands, skin ulceration, periungual erythema, subcutaneous calcinosis, dysphagia, myalgia, myasthenia, arthritis, Raynaud' s phenomenon, interstitial lung disease, pulmonary hypertension and myocardial involvement), laboratory characteristics, immunological characteristics [including antinuclear antibodies, rheumatoid factors, myositis-associated autoantibodies (MAAs) and myositis-specific autoantibodies (MSAs)] and survival. The clinical and immunological characteristics and prognostic differences of OM and non-OM were compared. The Kaplan-Meier and Log Rank methods were used to analyze the survival.

RESULTS

A total of 368 patients were included. 23.9% (88/368) of IIMs patients were OM patients. Among the 88 OM patients, 85.2% (75/88) of them were female, and the median interval between disease onset and diagnosis was 13.5 months. The incidence of overlapped connective tissue diseases in the OM patients was dermatomyositis (DM) in 60.2%, polymyositis (PM) in 3.4%, immune-mediated necrotizing myopathy (IMNM) in 2.3% and anti-synthetase syndrome (ASS) in 34.1%. Compared with the non-OM patients, the proportion of the females in the OM patients was higher (85.2% vs. 72.1%, P=0.016), the OM patients had longer disease duration [13.5(4.5, 48.0) months vs. 4.0(2.0, 12.0) months, P < 0.001]. As for clinical characteristics, compared with the non-OM patients, the incidence of V-sign (25.0% vs. 44.6%, P=0.001) and periungual erythema (8.0% vs. 19.6%, P=0.013) were lower; the incidence of Raynaud's phenomenon (14.8% vs. 1.8%, P < 0.001), interstitial pneumonia (88.6% vs. 72.1%, P=0.001), pulmonary hypertension (22.7% vs. 7.5%, P < 0.001) and myocardial involvement (18.2% vs. 9.3%, P=0.033) were higher. As for immunological characteristics, compared with the non-OM patients, the incidence of elevated aspartate aminotransferase (AST) (31.8% vs. 45.0%, P=0.035) was lower and elevated C-reactive protein (CRP) (58.0% vs. 44.6%, P=0.037) was higher; the positive rates of antinuclear antibodies (ANA) (85.1% vs. 63.4%, P=0.001) and rheumatoid factors (RF) (40.2% vs. 17.8%, P < 0.001) and anti-Ro-52 (71.6% vs. 56.1%, P=0.038) in serum were higher. There was no significant difference in the survival between the OM patients and non-OM patients.

CONCLUSION

Pulmonary hypertension and myocardial involvement were frequently observed in OM.

A study on the mechanism of PP2A in the recovery of SCI in rats through downregulation of MMP-9 via MAPK signaling pathway

OBJECTIVE

The aim of this study was to investigate the mechanism of action of protein phosphatase 2A (PP2A) in the recovery of spinal cord injury (SCI) in rats by downregulating matrix metalloproteinase 9 (MMP-9) via the mitogen-activated protein kinase (MAPK) signaling pathway.

MATERIALS AND METHODS

A model of SCI was first successfully established in rats. A total of three groups were set, including: sham operation group (A group), SCI group (B group) and PP2A group (C group). The Basso, Beattie and Bresnahan (BBB) motor function score and inclined plane test were adopted to evaluate the motor ability and limb muscle strength of rats in each group. The water content in spinal cord tissues was detected as well. Quantitative Polymerase Chain Reaction (qPCR) assay was performed to analyze the messenger ribonucleic acid (mRNA) expression levels of MAPK, MMP-2, and MMP-9 in spinal cord tissues. The expressions of inflammatory factors tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6 in each group of rats were determined via enzyme-linked immunosorbent assay (ELISA). Western blotting (WB) was employed to measure the protein expression levels of MAPK, MMP-2 and MMP-9 in each group of rats. Additionally, the apoptosis of nerve cells in spinal cord tissues was analyzed through terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.

RESULTS

The BBB score was 8.8 points in C group at 5 d after operation, which was significantly different from that in B group (p<0.05). The slope in B and C groups was clearly lower than that in A group at each time point (p<0.001). Meanwhile, it was significantly higher in C group than that in B group at 5, 7 and 9 d (p<0.05). The edema rate rose notably in B group compared with A group (p<0.001). However, spinal cord edema was remarkably relieved after treatment with FRY720 (p<0.01), suggesting that PP2A agonist could treat SCI in rats. The levels of cytokines TNF-α, IL-1β and IL-6 were markedly higher in B group than those in A group (p<0.01). However, they were significantly reduced after treatment with PP2A agonist (p<0.01). In comparison with A group, B group exhibited remarkably decreased mRNA expression of MAPK and elevated mRNA expressions of MMP-2 and MMP-9 (p<0.01). However, C group exhibited an upregulated mRNA expression of MAPK (p<0.05), a downregulated mRNA expression of MMP-9 (p<0.01), and an undifferentiated mRNA expression of MMP-2 (p>0.05). Compared with B group, the protein expression level of MAPK significantly increased (p<0.05), while that of MMP-9 evidently decreased in C group (p<0.05). Besides, no statistically significant difference was observed in the protein expression level of MMP-2 between C group and B group (p>0.05). Compared with that in A group, the apoptosis rate significantly increased in B group (p<0.001). In addition, the apoptosis rate was significantly lower in C group than that in B group, showing a statistically significant difference (p<0.01).

CONCLUSIONS

PP2A downregulates MMP-9 through the MAPK signaling pathway, thereby conducing to the recovery of SCI in rats.