Reduced Prefrontal-Thalamic Theta Flow During Working Memory Retrieval in APP/PS1 Mice.

Background: Working memory deficits in Alzheimer's disease (AD) are linked to impairments in the retrieval of stored memory information. However, research on the mechanism of impaired working memory retrieval in Alzheimer's disease is still lacking. Objective: The medial prefrontal cortex (mPFC) and mediodorsal thalamus (MD) are involved in memory retrieval. The purpose of this study is to investigate the functional interactions and information transmission between mPFC and MD in the AD model. Methods: We recorded local field potentials from mPFC and MD while the mice (APP/PS1 transgenic model and control) performed a T-maze spatial working memory task. The temporal dynamics of oscillatory activity and bidirectional information flow between mPFC and MD were assessed during the task phases. Results: We mainly found a significant decrease in theta flow from mPFC to MD in APP/PS1 mice during retrieval. Conclusions: Our results indicate an important role of the mPFC-MD input for retrieval and the disrupted information transfer from mPFC to MD may be the underlying mechanism of working memory deficits in APP/PS1 mice.

Hippocampal-prefrontal high-gamma flow during performance of a spatial working memory.

Working memory refers to a system that provides temporary storage and manipulation of the information necessary for complex cognitive tasks. The prefrontal cortex (PFC) and hippocampus (HPC) are major structures contributing to working memory. Accumulating evidence suggests that the HPC-PFC interactions are critical for the successful execution of working memory tasks. Nevertheless, the directional information transmission within the HPC-PFC pathway remains unclear. Using simultaneous multi-electrode recordings, we recorded local field potentials (LFPs) from the medial prefrontal cortex (mPFC) and ventral hippocampus (vHPC) while the rats performed a spatial working memory task in a Y-maze. The directionality of functional interactions between mPFC and vHPC was assessed using the phase-slope index (PSI). Our findings revealed a frequency-specific oscillatory synchrony in the two regions during the spatial working memory task. Furthermore, an increased high-gamma flow from vHPC to mPFC manifested exclusively during correctly performed trials, not observed during incorrect ones. This suggests that the enhanced high-gamma flow reflects behavioral performance in working memory. Consequently, our results indicate an major role of directional frequency-specific communication in the hippocampal-frontal circuit during spatial working memory, providing a potential mechanism for working memory.

The flower of Abelmoschus manihot (L.) medik exerts antioxidant effects by regulating the Nrf2 signalling pathway in scald injury.

Scald is a common skin injury in daily life. It is well known that skin burns are associated with inflammation and oxidative stress. In our previous study, we found that Abelmoschus manihot (L.) medik had excellent therapeutic effects on scald-induced inflammation, but its effect on scald-induced oxidative stress was not reported. In this study, a deep second-degree scald model in mice was established, and the wound healing rate, healing time, malondialdehyde (MDA) and total superoxide dismutase (T-SOD) levels, and nuclear factor erythroid 2-related Factor 2 (Nrf2) expression in wound tissue were measured to evaluate the scald wound healing performance of extraction from A. manihot (L.) medik (EAM). Scalding activity in mice was examined in vivo by hot water-induced finger swelling. The treatment scald activities were also examined in vivo by subjecting mice to thermal water-induced digit swelling. Additionally, the antioxidant effect of EAM on fibroblasts was also used to determine the mechanism in vitro. The results showed that EAM not only decreased the wound healing time but also effectively regulated the levels of oxidising, MDA and T-SOD in wound tissue. Concurrently, EAM suppressed digit swelling and hyperalgesia. Furthermore, EAM had a significant protective effect on NIH-3T3 cells after H2 O2 injury by regulating the Nrf2 signalling pathway against oxidative injury. Therefore, EAM is a promising drug for the treatment of scald-induced inflammation.

Tracheoesophageal fistula closure after staged dose-escalated radiotherapy for esophageal squamous cell carcinoma: a case report.

An esophageal fistula can be caused by an esophageal tumor as well as the surgery, radiotherapy (RT), or chemoradiotherapy used to treat the tumor. The most dangerous complications are massive hemoptysis and asphyxia. This report describes a 58-year-old man with a >1-month history of dysphagia and hemoptysis. Contrast-enhanced computed tomography revealed a tumor in the upper esophagus and a tracheoesophageal fistula. Esophagography revealed a large lesion measuring approximately 8 cm in length. Esophagogastroduodenoscopy showed an ulcerated tumor with raised margins originating 22 cm from the incisors, and histologic examination of a biopsy specimen indicated squamous cell carcinoma. The tumor was finally classified as stage IVA (T4bN0M0) esophageal squamous cell carcinoma. Massive hemoptysis occurred after the patient was admitted to the hospital. Therefore, we applied staged dose-escalated RT in three stages (6.0 Gy in 5 fractions, 7.5 Gy in 5 fractions, and 46.8 Gy in 26 fractions) to decrease the rate of tumor shrinkage brought on by RT and give the normal tissue enough time to close the fistula. Finally, the hemoptysis resolved and the patient's symptoms were significantly improved. Contrast-enhanced chest computed tomography revealed shrinkage of the tumor. In conclusion, staged dose-escalated RT can be applied for esophageal fistula closure.

Decreased phase information transfer from the mPFC to the BLA: During exploratory behavior in CUMS rats.

Introduction: Depression is a mental disorder characterized by aberrant exploratory behavior. Environmental factors, such as chronic stress, are commonly used to induce depression-like behavior in rodent models. The medial prefrontal cortex (mPFC) and the basolateral amygdala (BLA) are crucial sites in subjects with chronic stress-induced depression. The transmission of amplitude information from the mPFC to the BLA was abated during exploratory behavior in depressive rats; however, the nature of the phase interaction between these two sites remains unknown. Methods: We used chronic unpredictable mild stress (CUMS) to model depression in rats and acquired local field potentials (LFPs) via multiple electrodes implanted in the mPFC and the BLA while rats (both the control and CUMS groups, respectively) were allowed to explore freely in an open field. The weighted phase lag index (WPLI) within the mPFC and the BLA and phase transfer entropy (PTE) from the mPFC to BLA were computed for two groups of rats (control and CUMS rats) to quantify the phase information transmission. Results: Rats subjected to CUMS showed a decrease in exploratory behavior. The WPLI within the mPFC and the BLA showed strikingly higher phase synchrony at theta frequencies (4-12 Hz) than other frequency bands during exploratory behavior in both the control and CUMS groups. The results of theta PTE from the mPFC to BLA showed that PTE was significantly decreased in the CUMS group compared with the control group. Discussions: These findings demonstrated that attenuated phase information transfer might restrain exploratory behavior in CUMS rats.

Mucosa-associated lymphoid tissue lymphoma of the trachea treated with radiotherapy: A case report.

BACKGROUND: Mucosa-associated lymphoid tissue (MALT) lymphoma originates in the marginal zone of lymphoid tissue. lung is one of the most frequent non-gastrointestinal organs involved, here known as bronchus-associated lymphoid tissue (BALT) lymphoma. BALT lymphoma of unknown etiology, and most patients are asymptomatic. The treatment of BALT lymphoma is controversial. CASE SUMMARY: A 55-year-old man admitted to hospital had a three-month history of progressively coughing up yellow sputum, chest stuffiness, and shortness of breath. Fiberoptic bronchoscopy revealed mucosal visible beaded bumps 4 cm from the tracheal carina at 9 o 'clock and 3 o 'clock, the right main bronchus, and the right upper lobe bronchus. Biopsy specimens showed MALT lymphoma. Computed tomography virtual bronchoscopy (CTVB) showed uneven main bronchial wall thickening and multiple nodular protrusion. BALT lymphoma stage IE was diagnosed after a staging examination. We treated the patient with radiotherapy (RT) alone. A total dose of 30.6 Gy/17 f/25 d was given. The patient had no obvious adverse reactions during RT. The CTVB was repeated after RT and showed that the right side of the trachea was slightly thickened. CTVB was repeated 1.5 mo after RT and again showed that the right side of the trachea was slightly thickened. Annual CTVB showed no signs of recurrence. The patient now has no symptoms. CONCLUSION: BALT lymphoma is an uncommon disease and shows good prognosis. The treatment of BALT lymphoma is controversial. In recent years, less invasive diagnostic and therapeutic approaches have been emerging. RT was effective and safe in our case. The use of CTVB could provide a noninvasive, repeatable, and accurate method in diagnosis and follow-up.

Directional prefrontal-thalamic information flow is selectively required during spatial working memory retrieval.

Introduction: Spatial working memory is a kind of short-term memory that allows temporarily storing and manipulating spatial information. Evidence suggests that spatial working memory is processed through three distinctive phases: Encoding, maintenance, and retrieval. Though the medial prefrontal cortex (mPFC) and mediodorsal thalamus (MD) are involved in memory retrieval, how the functional interactions and information transfer between mPFC and MD remains largely unclear. Methods: We recorded local field potentials (LFPs) from mPFC and MD while mice performed a spatial working memory task in T-maze. The temporal dynamics of functional interactions and bidirectional information flow between mPFC and MD was quantitatively assessed by using directed transfer function. Results: Our results showed a significantly elevated information flow from mPFC to MD, varied in time and frequency (theta in particular), accompanying successful memory retrieval. Discussion: Elevated theta information flow, a feature that was absent on error trials, indicates an important role of the directional information transfer from mPFC to MD for memory retrieval.

Behavioral state-dependent oscillatory activity in prefrontal cortex induced by chronic social defeat stress.

Chronic stress contributes to the onset and exacerbation of major depressive disorder (MDD) through the oscillatory activity in the prefrontal cortex (PFC). However, the oscillations on which chronic social stress converges to yield the behavioral state of social avoidance are largely unknown. Here, we use a chronic social defeat stress model and in vivo electrophysiological recordings to uncover a novel neurophysiological measure that predicts the social behavioral state in stressed animals. First, in this study, we find that chronic social defeat stress model induces depression-like behaviors (anhedonia and social avoidance). Second, we find statistically significant differences in PFC oscillatory activity across different frequency ranges in social behavioral state, and the oscillatory activity correlates with stress-induced behavioral state. Finally, we show that the social behavioral states are accurately decoded from the oscillatory activity based on machine learning. Together, these results demonstrate that naturally occurring differences in PFC oscillation underlie the social behavioral state that accompanies the emergence of stress-induced behavioral dysfunction.

Decreased Phase-Amplitude Coupling Between the mPFC and BLA During Exploratory Behaviour in Chronic Unpredictable Mild Stress-Induced Depression Model of Rats.

Depression is a common neuropsychiatric illness observed worldwide, and reduced interest in exploration is one of its symptoms. The control of dysregulated medial prefrontal cortex (mPFC) over the basolateral amygdala (BLA) is related to depression. However, the oscillation interaction in the mPFC-BLA circuit has remained elusive. Therefore, this study used phase-amplitude coupling (PAC), which provides complicated forms of information transmission by the phase of low-frequency rhythm, modulating the amplitude of high-frequency rhythm, and has a potential application for the treatment of neurological disease. The chronic unpredictable mild stress (CUMS) was used to prepare the rat models of depression. Moreover, multichannel in vivo recording was applied to obtain the local field potentials (LFPs) of the mPFC, the BLA in rats in control, and CUMS groups, while they explored the open field. The results showed prominent coupling between the phase of theta oscillation (4-12 Hz) in the mPFC and the amplitude of high-gamma oscillation (70-120 Hz) in the BLA. Compared to the control group, this theta-gamma PAC was significantly decreased in the CUMS group, which was accompanied by the diminished exploratory behaviour. The results indicate that the coupling between the phase of theta in the mPFC and the amplitude of gamma in the BLA is involved in exploratory behaviour, and this decreased coupling may inhibit exploratory behaviour of rats exposed to CUMS.

Clinicopathological features of patients with transformation from EGFR mutant lung adenocarcinoma to small cell lung cancer.

BACKGROUND: Recently, an increasing number of cases with transformation from lung adenocarcinoma to small cell lung cancer (SCLC) have been identified, but few studies have investigated the clinical, pathological as well as molecular characteristics of these cases. This study aimed to summarize and analyze these features. METHODS: We retrospectively collected data including clinical information, laboratory examination results, radiological and pathological findings of ten patients, who were confirmed to undergo SCLC transformation following treatment from January 2014 to January 2020. RESULTS: The median time of treatment (targeted agents) was 14 months, and the median time interval of SCLC transformation following treatment was 24 months. Immunohistochemical indicators after transformation showed positive thyroid transcription factor 1 (TTF1), synaptophysin (Syn), CD56, and AE1/AE3, highly expressed Ki67, as well as negative programmed cell death-ligand 1 (PD-L1). Compared with the patients who received targeted therapy first, those patients who received chemotherapy followed by targeted therapy presented longer time intervals to transformation (36 vs. 22 months). Genetic testing after transformation showed that eight patients still maintained the original epidermal growth factor receptor (EGFR) mutation types. The median progression-free survival (PFS) after transformation was 5 months, and the median survival time after transformation was 10 months in seven patients who died. CONCLUSIONS: Lung adenocarcinomas, once transformed to SCLC, progress rapidly and lead to poorer prognosis. After transformation, most of the patients maintain the original EGFR mutation types.

Reduced Information Transmission of Medial Prefrontal Cortex to Basolateral Amygdala Inhibits Exploratory Behavior in Depressed Rats.

Depression is a mental and neurological disease that reduces the desire for exploration. Dysregulation of the information transmission between medial prefrontal cortex (mPFC) and basolateral amygdala (BLA) is associated with depression. However, which direction of information transmission (mPFC-BLA or BLA-mPFC) related to the decline of exploratory interests in depression is unclear. Therefore, it is important to determine what specific changes occur in mPFC and BLA information transmission in depressed rats during exploratory behavior. In the present study, local field potentials (LFPs) were recorded via multi-electrodes implanted in the mPFC and BLA for the control and depression groups of rats when they were exploring in an open field. The theta band was determined to be the characteristic band of exploratory behavior. The direct transfer function (DTF) was used to calculate the mPFC and BLA bidirectional information flow (IF) to measure information transmission. Compared with the control group, the theta IF of mPFC-BLA in the depression group was significantly reduced, and there was no significant difference in theta IF of BLA-mPFC between the two groups. Our results indicated that the reduction of mPFC-BLA information transmission can inhibit the exploratory behavior of depressed rats.

Characterization of the endothiapepsin-like protein in the entomopathogenic fungus Beauveria bassiana and its virulence effect on the silkworm, Bombyx mori.

Endothiapepsin is an aspartic proteinase that was first isolated from the plant pathogenic fungus Endothia parasitica. In previous studies, we reported on three endothiapepsin-like proteins in the entomopathogenic fungus Beauveria bassiana; the genes were up-regulated in B. bassiana hyper-virulent strain GXsk1011 at early stage infection in the silkworm. However, whether these proteins play a role in pathogenicity or not remains unknown. In this study, we cloned one protein, BbepnL-1 gene (BBA-07766), that has 98% homology with B. bassiana strain Bb2860, and expressed it in the yeast Pichia pastoris to investigate its function. The endothiapepsin-like protein is a secreted proteinase of molecular weight approximately 40 kDa. It has an N-glycosylation site and a mutation in the C-terminal conserved domain- a Thr was mutated to Gly in B. bassiana GXsk1011 and is different than the endothiapepsin of Endothia parasitica. The recombinant endothiapepsin-like protein showed enzyme activity and degraded the protein components of the silkworm cuticle. To further investigate the activity of the endothiapepsin-like protein, we knocked out the gene BbepnL-1 and showed that the loss of BbepnL-1 reduced the virulence in the silkworm. These results demonstrated that the endothiapepsin-like protein of B. bassiana is a virulence factor.

Kinetics study on non-thermal plasma mineralization of adsorbed toluene over γ-Al2O3 hybrid with zeolite.

Non-thermal plasma mineralization of the adsorbed toluene over γ-Al2O3 hybrid with 13X, ZSM-5, and HY was investigated in a sequential adsorption and plasma oxidation system. The γ-Al2O3-13X was shown to have a better plasma oxidation performance with fewer by-products as compared to γ-Al2O3-ZSM-5 and γ-Al2O3-HY, which was due to its better discharge performance and O3 decomposition ability. For all of the tested materials, the plasma mineralization of the adsorbed toluene process had a good match with the pseudo-second-order kinetic model: kt = 1/n - 1/no, where n0 and n are the amount of adsorbed toluene (mmol) at discharge time = 0 and t, respectively. The overall reaction constant (k) was shown to be affected by the packing materials. The reason for the kinetic model following the pseudo-second-order in the sequential process was analyzed based on the chemical reaction and mineralization mechanism.

Information transmission in HPC-PFC network for spatial working memory in rat.

Spatial working memory is a short-term system for the temporary holding and manipulation of spatial information. Evidence shows that the hippocampus (HPC) and prefrontal cortex (PFC) play important roles in spatial working memory. Though the communication between HPC and PFC is recognized as essential for successful execution of spatial working memory tasks, the directional information transmission in the HPC-PFC network is largely unclear. Therefore, in the present study, neuronal activity was recorded from rat ventral hippocampus (vHPC) and medial prefrontal cortex (mPFC) while the rats performed a spatial working memory task in Y-maze. Then the causality connectivity among the spikes from recorded neurons was estimated using the maximum likelihood estimation and the information flow in the vHPC-mPFC network was calculated to investigate the functional dynamics of the vHPC-mPFC information transmission. Our results showed the increased bidirectional information flow in the vHPC-mPFC network during the spatial working memory task. Both directions of information flow were observed only on trials in which the animal subsequently made the correct response, indicating that the increase in information flow predicted memory accuracy. Furthermore, the information flow from vHPC to mPFC was remarkably higher and preceded that from mPFC to vHPC. These findings suggest that the direct vHPC-mPFC information transmission may be predominant for spatial working memory in rat.

High-throughput identification of G protein-coupled receptor modulators through affinity mass spectrometry screening.

G protein-coupled receptors (GPCRs) represent the largest class of cell surface proteins and thus constitute an important family of therapeutic targets. Therefore, significant effort has been put towards the identification of novel ligands that can modulate the activity of a GPCR target with high efficacy and selectivity. However, due to limitations inherent to the most common techniques for GPCR ligand discovery, there is a pressing need for more efficient and effective ligand screening methods especially for the identification of potential allosteric modulators. Here we present a high-throughput, label-free and unbiased screening approach for the identification of small molecule ligands towards GPCR targets based on affinity mass spectrometry. This new approach features the usage of target-expressing cell membranes rather than purified proteins for ligand screening and allows the detection of both orthosteric and allosteric ligands targeting specific GPCRs. Screening a small compound library with this approach led to the rapid discovery of an antagonist for the 5-HT receptor and four positive allosteric modulators for GLP-1 receptor that were not previously reported.

Comparison of preoperative concurrent chemoradiotherapy with chemotherapy alone in patients with locally advanced siewert II and III adenocarcinoma of the esophagogastric junction.

PURPOSE: Preoperative therapy improves overall survival (OS) after surgery in patients with adenocarcinoma of the esophagogastric junction (AEG). We aimed to retrospectively analyze whether preoperative chemoradiotherapy (CRT) could improve the prognosis of patients with locally advanced Siewert II and III AEG comparing with preoperative chemotherapy alone (CT). PATIENTS AND METHODS: From March 2012 to December 2015, 170 patients with locally advanced (cT3-4NxM0) Siewert II and III AEG were treated with preoperative CRT or CT in Hebei Medical University Fourth Hospital, and 123 patients were included in this study to compare the effects of preoperative CRT with CT. RESULTS: R0 resection rate was 96.7% in CRT group and 82.5% in CT group (P = .016). The pathological complete response was 16.7% after CRT group and 3.2% after CT (P = .015). The median follow-up time was 20 months. The 1- and 3-year OS were 89.4%, 79.2% in CRT group and 88.2%, 58.0% in CT group (P = .016; HR = 0.40, 95% confidence interval 0.21-0.76). The 1- and 3-year PFS were 87.3%, 73.5% in CRT group and 72.8%, 42.8% in CT group (P = .014; HR = 0.46, 95% confidence interval 0.24-0.86). Multivariate analysis showed that clinical T stage, adjuvant chemotherapy cycles and histologic differentiation were shown to be the independent prognostic factors for OS, and postoperative pathologic N stage was shown to be the independent prognostic factor for PFS. CONCLUSION: For the patients with locally advanced AEG, the addition of radiotherapy to preoperative chemotherapy can improve survival with safety, but is not an independent prognostic factor for OS and PFS.

Repetitive Transcranial Magnetic Stimulation Reverses Aß1-42-induced Dysfunction in Gamma Oscillation during Working Memory.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disease that gradually induces cognitive deficits in the elderly and working memory impairment is typically observed in AD. Amyloid-ß peptide (Aß) is a causative factor for the cognitive impairments in AD. Gamma oscillations have been recognized to play important roles in various cognitive functions including working memory. Previous study reported that Aß induces gamma oscillation dysfunction in working memory. OBJECTIVE: Although repetitive transcranial magnetic stimulation (rTMS) represents a technique for noninvasive stimulation to induce cortical activity and excitability changes and has been accepted for increasing brain excitability and regulating cognitive behavior, the question whether rTMS can reserve the Aß-induced gamma oscillation dysfunction during working memory remains unclear. The present study aims to investigate the effect of rTMS to the Aß-induced gamma oscillation dysfunction during working memory. METHOD: The present study investigates the rTMS-modulated gamma oscillation in Aß1-42-induced memory deficit. Adult SD rats were divided into four groups: Aß, Con, Aß+rTMS and Con+rTMS. 16-channel local field potentials (LFPs) were recorded from rat medial prefrontal cortex while the rats performed a Y-maze working memory task. Gamma oscillation among LFPs was measured by coherence. RESULTS: The results show that rTMS improved the behavior performance and enhanced gamma oscillation for the Aß-injected subjects. CONCLUSION: These results indicate that rTMS may reserve the Aß-induced dysfunction in gamma oscillation during working memory and thus result in potential benefits for working memory.

Directional hippocampal-prefrontal interactions during working memory.

Working memory refers to a system that is essential for performing complex cognitive tasks such as reasoning, comprehension and learning. Evidence shows that hippocampus (HPC) and prefrontal cortex (PFC) play important roles in working memory. The HPC-PFC interaction via theta-band oscillatory synchronization is critical for successful execution of working memory. However, whether one brain region is leading or lagging relative to another is still unclear. Therefore, in the present study, we simultaneously recorded local field potentials (LFPs) from rat ventral hippocampus (vHPC) and medial prefrontal cortex (mPFC) and while the rats performed a Y-maze working memory task. We then applied instantaneous amplitudes cross-correlation method to calculate the time lag between PFC and vHPC to explore the functional dynamics of the HPC-PFC interaction. Our results showed a strong lead from vHPC to mPFC preceded an animal's correct choice during the working memory task. These findings suggest the vHPC-leading interaction contributes to the successful execution of working memory.

Quantification and comparison the dosimetric impact of two treatment couch model in VMAT.

The use of Monte Carlo treatment planning systems (TPS) in radiation therapy has increased the dosimetric accuracy of VMAT treatment sequences. However, this accuracy is compromised by not including the treatment couch into the treatment planning process. Therefore, the impact of the treatment couch on radiation delivery output was determined, and two different couch models (uniform couch model A vs two components model B) were included and tested in the Monaco TPS to investigate which model can better quantify the couch influence on radiation dose. Relative attenuation measurements were performed following procedures outlined by TG-176 with three phantom positions for A-B direction: on the left half (L), in the center (C) and on the right half (R) of the couch. As well as absolute dose comparison of static fields of 10 × 10 cm2 that were delivered through the couch tops with that calculated in the TPS with the couch model at 2 mm and 5 mm computing grid size respectively. The most severe percentage deviation was 4.60% for the phantom positioned at the left half of the couch with 5 mm grid size at gantry angle 120°. The couch model was included in the TPS with a uniform ED of 0.26 g/cm3 or a two component model with a fiber 0.52 g/cm3 and foam core 0.1 g/cm3 . After including the treatment couch, the maximum mean dose attenuation was reduced from 3.68% without couch included to (0.60, 0.83, 0.72, and 1.02) % for model A and model B at 2 and 5 mm voxel grid size. The results obtained showed that Model A performed better than the model B, demonstrating lower deviations from measurements and better robustness against dose grid resolution changes. Considering the results of this study, we propose the systematic introduction of the couch Model A in clinical routine. All the reported findings are valid for the Elekta iBEAM® evo Extension 415 couch and these methods can also be used for other couch model.

Transcriptomic analysis of two Beauveria bassiana strains grown on cuticle extracts of the silkworm uncovers their different metabolic response at early infection stage.

Beauveria bassiana is an important entomopathogenic fungus which not only widely distributes in the environment but also shows phenotypic diversity. However, the mechanism of pathogenic differences among natural B. bassiana strains has not been revealed at transcriptome-wide level. In the present study, in order to explore the mechanism, two B. bassiana strains with different pathogenicity were isolated from silkworms (Bombyx mori L.) and selected to analyze the gene expression of early stage by culturing on cuticle extracts of the silkworm and using RNA-sequencing technique. A total of 2108 up-regulated and 1115 down-regulated genes were identified in B. bassiana strain GXsk1011 (hyper-virulent strain) compared with B. bassiana strain GXtr1009 (hypo-virulent strain), respectively. The function categorization of differential expressed genes (DEGs) showed that most of them involved in metabolic process, biosynthesis of secondary metabolites, catalytic activity, and some involved in nutrition uptake, adhesion and host defense were also noted. Based on our data, distinct pathogenicity among different strains of B. bassiana may largely attribute to unique gene expression pattern which differed at very early infection process. Most of the genes involved in conidia adhesion, cuticle degradation and fungal growth were up-regulated in hyper-virulent B. bassiana strain GXsk1011. Furthermore, in combination with fungal growth analysis, our research provided a clue that fungal growth may also play an important role during early infection process. The results will help to explain why different B. bassiana strains show distinct pathogenicity on the same host even under same condition. Moreover, the transcriptome data were also useful for screening potential virulence factors.