Automatic Rejection based on Tissue Signal (ARTS) for motion-corrected quantification of cerebral venous oxygenation in neonates and older adults.

OBJECTIVE: Cerebral venous oxygenation (Yv) is a key parameter for the brain's oxygen utilization and has been suggested to be a valuable biomarker in various brain diseases including hypoxic ischemic encephalopathy in neonates and Alzheimer's disease in older adults. T2-Relaxation-Under-Spin-Tagging (TRUST) MRI is a widely used technique to measure global Yv level and has been validated against gold-standard PET. However, subject motion during TRUST MRI scan can introduce considerable errors in Yv quantification, especially for noncompliant subjects. The aim of this study was to develop an Automatic Rejection based on Tissue Signal (ARTS) algorithm for automatic detection and exclusion of motion-contaminated images to improve the precision of Yv quantification. METHODS: TRUST MRI data were collected from a neonatal cohort (N = 37, 16 females, gestational age = 39.12 ± 1.11 weeks, postnatal age = 1.89 ± 0.74 days) and an older adult cohort (N = 223, 134 females, age = 68.02 ± 9.01 years). Manual identification of motion-corrupted images was conducted for both cohorts to serve as a gold-standard. 9.3% of the images in the neonatal datasets and 0.4% of the images in the older adult datasets were manually identified as motion-contaminated. The ARTS algorithm was trained using the neonatal datasets. TRUST Yv values, as well as the estimation uncertainty (ΔR2) and test-retest coefficient-of-variation (CoV) of Yv, were calculated with and without ARTS motion exclusion. The ARTS algorithm was tested on datasets of older adults: first on the original adult datasets with little motion, and then on simulated adult datasets where the percentage of motion-corrupted images matched that of the neonatal datasets. RESULTS: In the neonatal datasets, the ARTS algorithm exhibited a sensitivity of 0.95 and a specificity of 0.97 in detecting motion-contaminated images. Compared to no motion exclusion, ARTS significantly reduced the ΔR2 (median = 3.68 Hz vs. 4.89 Hz, P = 0.0002) and CoV (median = 2.57% vs. 6.87%, P = 0.0005) of Yv measurements. In the original older adult datasets, the sensitivity and specificity of ARTS were 0.70 and 1.00, respectively. In the simulated adult datasets, ARTS demonstrated a sensitivity of 0.91 and a specificity of 1.00. Additionally, ARTS significantly reduced the ΔR2 compared to no motion exclusion (median = 2.15 Hz vs. 3.54 Hz, P < 0.0001). CONCLUSION: ARTS can improve the reliability of Yv estimation in noncompliant subjects, which may enhance the utility of Yv as a biomarker for brain diseases.

Longitudinal changes in brain oxygen extraction fraction (OEF) in older adults: Relationship to markers of vascular and Alzheimer's pathology.

INTRODUCTION: Oxygen extraction fraction (OEF) reflects the balance between oxygen delivery and consumption. We longitudinally measured OEF in older adults to examine the relationship with markers of Alzheimer's disease (AD) and vascular pathology. METHODS: One hundred thirty-seven participants were studied at two time-points at an interval of 2.16 years. OEF was measured using T2 -relaxation-under-spin-tagging (TRUST) magnetic resonance imaging (MRI). The association between OEF and vascular risks, white matter hyperintensities (WMH), cerebrospinal fluid (CSF) measures of amyloid beta (Aß), total tau (t-tau), and phosphorylated tau 181 (p-tau181) was examined. RESULTS: OEF increased from baseline to follow-up. The increase in OEF was more prominent in individuals with high vascular risks compared to those with low vascular risks, and was associated with progression of vascular risks and the growth in WMH volume. OEF change was not related to CSF markers of AD pathology or their progression. DISCUSSION: Longitudinal OEF change in older adults is primarily related to vascular pathology.

Dataset of relationship between longitudinal change in cognitive performance and functional connectivity in cognitively normal older individuals.

The data show an association between measured and predicted changes in cognitive performance in older adults who are cognitively normal. Changes in cognitive performance over two years were assessed using the Cognitive Composite Score. The prediction of change in cognitive function was based on changes in pairwise functional connectivity between 80 gray matter regions examined by resting-state functional magnetic resonance imaging. A feature extraction process based on the Variable Importance Testing Approach (VITA) identified changes in 11 pairs of functional connections associated with the default mode network as features related to changes in cognitive performance. Linear and elastic net regression models were applied to these 11 features to predict changes in cognitive performance over two years. A relationship between the 11 features and the geriatric depression score was also shown. The dataset supplements the research findings in the "Changes in pairwise functional connectivity associated with changes in cognitive performance in cognitively normal older individuals: a two-year observational study" published in Oishi et al. (2022). The raw rs-fMRI correlation matrix and associated clinical data can be accessed upon request from the BIOCARD website (www.biocard-se.org) and can be reused for predictive model building.

Changes in pairwise functional connectivity associated with changes in cognitive performance in cognitively normal older individuals: A two-year observational study.

Neurobiological substrates of cognitive decline in cognitively normal older individuals have been investigated by resting-state functional magnetic resonance imaging, but little is known about the relationship between longitudinal changes in the whole brain. In this study, we examined two-year changes in functional connectivity among 80 gray matter areas and investigated the relationship to two-year changes in cognitive performance. A cross-validated permutation variable importance measure was applied to select features related to a change in cognitive performance. Age-corrected changes in eleven pairs of functional connections were selected as important features, all related to brain areas that belong to the default mode network. A linear regression model with cross-validation demonstrated a mean correlation coefficient of 0.55 between measured and predicted changes in the cognitive composite score. These results suggest that intra- and inter-network connections in the default mode network are associated with cognitive changes over two years among cognitively normal individuals.

Longitudinal Changes in Global Cerebral Blood Flow in Cognitively Normal Older Adults: A Phase-Contrast MRI Study.

BACKGROUND: Characterization of blood supply changes in older individuals is important in understanding brain aging and diseases. However, prior studies largely focused on cross-sectional design, thus change in cerebral blood flow (CBF) could not be assessed on an individual level. PURPOSE: To evaluate longitudinal short-term changes in global CBF in cognitively normal older adults. STUDY TYPE: Prospective, longitudinal, and cohort. POPULATION: One-hundred twenty-seven cognitive-normal participants (mean age 69 ± 7 years, 47 males) underwent serial MRI with an average follow-up time of 2.1 years. FIELD STRENGTH/SEQUENCE: 3 T phase-contrast (PC), three-dimensional magnetization-prepared-rapid-acquisition-of-gradient-echo (MPRAGE) and fluid-attenuated inversion recovery (FLAIR) MRI. ASSESSMENT: Total CBF was measured with PC MRI allowing assessment of quantitative flow in four major feeding arteries by a trained radiologist with >3 years' experience (O.K.). Brain volume was obtained from MPRAGE MRI and measured by T1-MultiAtlas MRICloud tool. The ratio between total CBF and brain volume yielded global CBF in mL/100 g/min. White matter hyperintensity (WMH) was measured automatically using a Bayesian probability approach on FLAIR. STATISTICAL TESTS: Linear mixed effect model was used to simultaneously assess cross-sectional age-differences and longitudinal age-changes in CBF. Spearman rank correlation was used to evaluate the relationship between CBF change and WMH progression. A P-value of <0.05 (two-tailed) was considered significant. RESULTS: Global CBF decreased with age at a longitudinal rate of -0.56 mL/100 g/min/year (95% confidence interval [CI]: -1.09, -0.03), compared to a cross-sectional rate of -0.26 mL/100 g/min/year (95% CI: -0.41, -0.11). Changes in CBF were significantly associated with progression of WMH (Spearman rank correlation r = -0.25), as those participants who had a more rapid CBF reduction had greater increases in WMH volumes and the relationship remained significant when adjusting for baseline vascular risk scores. Additionally, age-related changes in whole-brain volume were found to be -0.151%/year (95% CI: -0.186, -0.116). DATA CONCLUSION: These findings suggest that brain aging in older adults is accompanied by a rapid longitudinal reduction in CBF, the rate of which is associated with white matter damage. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Influence of age, lesion volume, and damage to dorsal versus ventral streams to viewer- and stimulus-centered hemispatial neglect in acute right hemisphere stroke.

We studied 156 individuals with acute, right hemisphere ischemic stroke on a battery of hemispatial neglect tests to distinguish between viewer-centered and stimulus-centered neglect and MRI diffusion weighted imaging. We identified the relative contributions of age, total lesion volume, and damage to subcortical and cortical grey matter regions as well as white matter tracts to both the severity and presence of significant viewer-centered and stimulus-centered neglect, using multivariable regression tests. We found that age, volume of lesion, and percent damage to the regions of interest were each independently associated with the severity of viewer-centered neglect (r2 = .31; p < .0001). However, only age (t = 3.20; p = .002) and percent damage to the angular gyrus (t = 2.63, p = .010), a dorsal stream area, predicted severity of viewer-centered neglect independently of the other variables. The same variables predicted the presence of significant viewer-centered neglect. In contrast, these variables did not significantly predict the severity of stimulus-centered neglect. However, we found that percent damage to ventral stream regions of interest (middle temporal gyrus, inferior temporal gyrus, fusiform gyrus, inferior frontal occipital gyrus, sagittal stratum, along with total infarct volume were associated with the presence of significant stimulus-centered neglect (pseudo r2 = .70, p < .0004). Only percent damage to right inferior temporal gyrus predicted stimulus-centered neglect independently of the other variables (p = .018).

Developmental trajectories of the human embryologic brain regions.

Vertebrate brains commonly consist of five basic embryologic anatomical regions: telencephalon; diencephalon; mesencephalon; metencephalon; and myelencephalon. The proportions of these regions vary widely across species and developmental stages. Investigation of their growth trajectories, therefore, has the potential to provide an understanding of the substrates of inter-species variation in neuroanatomy and function. To investigate the volumetric growth trajectories, structural magnetic resonance imaging (MRI) scans obtained from 618 healthy children (334 boys, 284 girls; ages 3-17 years old) were parcellated into five regions for the volume quantification. The sex- and region-specific growth trajectories were identified, and the most active growth was seen in the mesencephalon for both boys and girls. Whether similar regional growth patterns are seen in other species, or whether such patterns are related to evolution, are important questions that must be elucidated in the future.

A Multi-Atlas Label Fusion Tool for Neonatal Brain MRI Parcellation and Quantification.

Structure-by-structure analysis, in which the brain magnetic resonance imaging (MRI) is parcellated based on its anatomical units, is widely used to investigate chronological changes in morphology or signal intensity during normal development, as well as to identify the alterations seen in various diseases or conditions. The multi-atlas label fusion (MALF) method is considered a highly accurate parcellation approach, and anticipated for clinical application to quantitatively evaluate early developmental processes. However, the current MALF methods, which are designed for neonatal brain segmentations, are not widely available. In this study, we developed a T1-weighted, neonatal, multi-atlas repository and integrated it into the MALF-based brain segmentation tools in the cloud-based platform, MRICloud. The cloud platform ensures users instant access to the advanced MALF tool for neonatal brains, with no software or installation requirements for the client. The Web platform by braingps.mricloud.org will eliminate the dependence on a particular operating system (eg, Windows, Macintosh, or Linux) and the requirement for high computational performance of the user's computers. The MALF-based, fully automated, image parcellation could achieve excellent agreement with manual parcellation, and the whole and regional brain volumes quantified through this method demonstrated developmental trajectories comparable to those from a previous publication. This solution will make the latest MALF tools readily available to users, with minimum barriers, and will expedite and accelerate advancements in developmental neuroscience research, neonatology, and pediatric neuroradiology.

Ventricular Volume Dynamics During the Development of Adult Chronic Communicating Hydrocephalus in a Rodent Model.

INTRODUCTION: The pathophysiology of normal-pressure hydrocephalus and the correlation with its symptomatology is not well understood. OBJECTIVE: To monitor and evaluate the enlargement patterns of the ventricular system for each ventricle and its correlation with the presenting symptoms. METHODS: Bilateral kaolin injection into the subarachnoid space overlying the cranial convexities was done in 18 adult rats. Magnetic resonance imaging was performed on an 11.7-T scanner 15, 60, 90, and 120 days after injection. Volumes of the ventricular system were measured for each ventricle and correlated with biweekly behavioral findings. RESULTS: There was a progressive increase in the ventricular volume for the lateral ventricles since day 15 in the kaolin-injected animals. There was a nonsignificant trend in volume growth for the third ventricle, but its enlargement was synchronous with the lateral ventricles. No significant change for the fourth ventricle. No symptoms were detected in the first 60 days. Association was found between the ventricular volume and locomotor changes. In addition, the odds of locomotor symptoms increased by 3% for every additional cubic millimeter of volume in the left (P < 0.001) and right (P = 0.023) ventricles, and for the total magnetic resonance imaging volume by 1% (P = 0.013). CONCLUSIONS: Expansion of the lateral ventricles maintained similar proportions over time, accompanied by a synchronous third ventricular expansion with less proportion and a nonsignificant fourth enlargement. Lateral ventricles enlarged most in those animals that were to develop late locomotor deterioration. Further research using this animal model combined with different radiologic imaging techniques, such as diffusion tensor imaging and perfusion studies, is recommended.

Impaired Recognition of Emotional Faces after Stroke Involving Right Amygdala or Insula.

Despite its basic and translational importance, the neural circuitry supporting the perception of emotional faces remains incompletely understood. Functional imaging studies and chronic lesion studies indicate distinct roles of the amygdala and insula in recognition of fear and disgust in facial expressions, whereas intracranial encephalography studies, which are not encumbered by variations in human anatomy, indicate a somewhat different role of these structures. In this article, we leveraged lesion-mapping techniques in individuals with acute right hemisphere stroke to investigate lesions associated with impaired recognition of prototypic emotional faces before significant neural reorganization can occur during recovery from stroke. Right hemisphere stroke patients were significantly less accurate than controls on a test of emotional facial recognition for both positive and negative emotions. Patients with right amygdala or anterior insula lesions had significantly lower scores than other right hemisphere stroke patients on recognition of angry and happy faces. Lesion volume within several regions, including the right amygdala and anterior insula, each independently contributed to the error rate in recognition of individual emotions. Results provide additional support for a necessary role of the right amygdala and anterior insula within a network of regions underlying recognition of facial expressions, particularly those that have biological importance or motivational relevance and have implications for clinical practice.

Change-point analysis data of neonatal diffusion tensor MRI in preterm and term-born infants.

The data presented in this article are related to the research article entitled "Mapping the Critical Gestational Age at Birth that Alters Brain Development in Preterm-born Infants using Multi-Modal MRI" (Wu et al., 2017) [1]. Brain immaturity at birth poses critical neurological risks in the preterm-born infants. We used a novel change-point model to analyze the critical gestational age at birth (GAB) that could affect postnatal development, based on diffusion tensor MRI (DTI) acquired from 43 preterm and 43 term-born infants in 126 brain regions. In the corresponding research article, we presented change-point analysis of fractional anisotropy (FA) and mean diffusivities (MD) measurements in these infants. In this article, we offered the relative changes of axonal and radial diffusivities (AD and RD) in relation to the change of FA and FA-based change-points, and we also provided the AD- and RD-based change-point results.

Stroke of bad luck?

We hypothesized that distinct acute right hemisphere lesions disrupt separate components of valuation and emotional response to winning and losing money and of emotional empathy in observing a partner win or lose money. We measured skin conductance response (SCR) and ratings of emotions when acute right hemisphere stroke patients or healthy controls won or lost money in roulette, or when they watched a partner win or lose. Our results showed that percentage of damage after stroke to right anterior insula and frontal operculum negatively correlated with both SCR to winning and losing and difference between rating wins versus losses.

Mapping the critical gestational age at birth that alters brain development in preterm-born infants using multi-modal MRI.

Preterm birth adversely affects postnatal brain development. In order to investigate the critical gestational age at birth (GAB) that alters the developmental trajectory of gray and white matter structures in the brain, we investigated diffusion tensor and quantitative T2 mapping data in 43 term-born and 43 preterm-born infants. A novel multivariate linear model-the change point model, was applied to detect change points in fractional anisotropy, mean diffusivity, and T2 relaxation time. Change points captured the "critical" GAB value associated with a change in the linear relation between GAB and MRI measures. The analysis was performed in 126 regions across the whole brain using an atlas-based image quantification approach to investigate the spatial pattern of the critical GAB. Our results demonstrate that the critical GABs are region- and modality-specific, generally following a central-to-peripheral and bottom-to-top order of structural development. This study may offer unique insights into the postnatal neurological development associated with differential degrees of preterm birth.

Picturing the Size and Site of Stroke With an Expanded National Institutes of Health Stroke Scale.

BACKGROUND AND PURPOSE: The National Institutes of Health Stroke Scale (NIHSS) includes minimal assessment of cognitive function, particularly in right hemisphere (RH) stroke. Descriptions of the Cookie Theft picture from the NIHSS allow analyses that (1) correlate with aphasia severity and (2) identify communication deficits in RH stroke. We hypothesized that analysis of the picture description contributes valuable information about volume and location of acute stroke. METHODS: We evaluated 67 patients with acute ischemic stroke (34 left hemisphere [LH]; 33 RH) with the NIHSS, analysis of the Cookie Theft picture, and magnetic resonance imaging, compared with 35 sex- and age-matched controls. We evaluated descriptions for total content units (CU), syllables, ratio of left:right CU, CU/minute, and percent interpretive CU, based on previous studies. Lesion volume and percent damage to regions of interest were measured on diffusion-weighted imaging. Multivariable linear regression identified variables associated with infarct volume, independently of NIHSS score, age and sex. RESULTS: Patients with RH and LH stroke differed from controls, but not from each other, on CU, syllables/CU, and CU/minute. Left:right CU was lower in RH compared with LH stroke. CU, syllables/CU, and NIHSS each correlated with lesion volume in LH and RH stroke. Lesion volume was best accounted by a model that included CU, syllables/CU, NIHSS, left:right CU, percent interpretive CU, and age, in LH and RH stroke. Each discourse variable and NIHSS score were associated with percent damage to different regions of interest, independently of lesion volume and age. CONCLUSIONS: Brief picture description analysis complements NIHSS scores in predicting stroke volume and location.

Delayed early developmental trajectories of white matter tracts of functional pathways in preterm-born infants: Longitudinal diffusion tensor imaging data.

Probabilistic maps of white matter pathways related to motor, somatosensory, auditory, visual, and limbic functions, and major white matter tracts (the corpus callosum, the inferior fronto-occipital fasciculus, and the middle cerebellar peduncle) were applied to evaluate the developmental trajectories of these tracts, using longitudinal diffusion tensor imaging (DTI) obtained in term-born and preterm-born healthy infants. Nineteen term-born and 30 preterm-born infants completed MR scans at three time points: Time-point 1, 41.6±2.7 postmenstrual weeks; Time-point 2, 46.0±2.9 postmenstrual weeks; and Time-point 3, 50.8±3.7 postmenstrual weeks. The DTI-derived scalar values (fractional anisotropy, eigenvalues, and radial diffusivity) of the three time points are available in this Data article.

Probabilistic maps of the white matter tracts with known associated functions on the neonatal brain atlas: Application to evaluate longitudinal developmental trajectories in term-born and preterm-born infants.

Diffusion tensor imaging (DTI) has been widely used to investigate the development of the neonatal and infant brain, and deviations related to various diseases or medical conditions like preterm birth. In this study, we created a probabilistic map of fiber pathways with known associated functions, on a published neonatal multimodal atlas. The pathways-of-interest include the superficial white matter (SWM) fibers just beneath the specific cytoarchitectonically defined cortical areas, which were difficult to evaluate with existing DTI analysis methods. The Jülich cytoarchitectonic atlas was applied to define cortical areas related to specific brain functions, and the Dynamic Programming (DP) method was applied to delineate the white matter pathways traversing through the SWM. Probabilistic maps were created for pathways related to motor, somatosensory, auditory, visual, and limbic functions, as well as major white matter tracts, such as the corpus callosum, the inferior fronto-occipital fasciculus, and the middle cerebellar peduncle, by delineating these structures in eleven healthy term-born neonates. In order to characterize maturation-related changes in diffusivity measures of these pathways, the probabilistic maps were then applied to DTIs of 49 healthy infants who were longitudinally scanned at three time-points, approximately five weeks apart. First, we investigated the normal developmental pattern based on 19 term-born infants. Next, we analyzed 30 preterm-born infants to identify developmental patterns related to preterm birth. Last, we investigated the difference in diffusion measures between these groups to evaluate the effects of preterm birth on the development of these functional pathways. Term-born and preterm-born infants both demonstrated a time-dependent decrease in diffusivity, indicating postnatal maturation in these pathways, with laterality seen in the corticospinal tract and the optic radiation. The comparison between term- and preterm-born infants indicated higher diffusivity in the preterm-born infants than in the term-born infants in three of these pathways: the body of the corpus callosum; the left inferior longitudinal fasciculus; and the pathway connecting the left primary/secondary visual cortices and the motion-sensitive area in the occipitotemporal visual cortex (V5/MT+). Probabilistic maps provided an opportunity to investigate developmental changes of each white matter pathway. Whether alterations in white matter pathways can predict functional outcomes will be further investigated in a follow-up study.

Gross feature recognition of Anatomical Images based on Atlas grid (GAIA): Incorporating the local discrepancy between an atlas and a target image to capture the features of anatomic brain MRI.

We aimed to develop a new method to convert T1-weighted brain MRIs to feature vectors, which could be used for content-based image retrieval (CBIR). To overcome the wide range of anatomical variability in clinical cases and the inconsistency of imaging protocols, we introduced the Gross feature recognition of Anatomical Images based on Atlas grid (GAIA), in which the local intensity alteration, caused by pathological (e.g., ischemia) or physiological (development and aging) intensity changes, as well as by atlas-image misregistration, is used to capture the anatomical features of target images. As a proof-of-concept, the GAIA was applied for pattern recognition of the neuroanatomical features of multiple stages of Alzheimer's disease, Huntington's disease, spinocerebellar ataxia type 6, and four subtypes of primary progressive aphasia. For each of these diseases, feature vectors based on a training dataset were applied to a test dataset to evaluate the accuracy of pattern recognition. The feature vectors extracted from the training dataset agreed well with the known pathological hallmarks of the selected neurodegenerative diseases. Overall, discriminant scores of the test images accurately categorized these test images to the correct disease categories. Images without typical disease-related anatomical features were misclassified. The proposed method is a promising method for image feature extraction based on disease-related anatomical features, which should enable users to submit a patient image and search past clinical cases with similar anatomical phenotypes.

RMD-1, a novel microtubule-associated protein, functions in chromosome segregation in Caenorhabditis elegans.

For proper chromosome segregation, the sister kinetochores must attach to microtubules extending from the opposite spindle poles. Any errors in microtubule attachment can induce aneuploidy. In this study, we identify a novel conserved Caenorhabditis elegans microtubule-associated protein, regulator of microtubule dynamics 1 (RMD-1), that localizes to spindle microtubules and spindle poles. Depletion of RMD-1 induces severe defects in chromosome segregation, probably through merotelic attachments between microtubules and chromosomes. Although rmd-1 embryos also have a mild defect in microtubule growth, we find that mutants of the microtubule growth regulator XMAP215/ZYG-9 show much weaker segregation defects. This suggests that the microtubule growth defect in rmd-1 embryos does not cause abnormal chromosome segregation. We also see that RMD-1 interacts with aurora B in vitro. Our results suggest that RMD-1 functions in chromosome segregation in C. elegans embryos, possibly through the aurora B-mediated pathway. Human homologues of RMD-1 could also bind microtubules, which would suggest a function for these proteins in chromosome segregation during mitosis in other organisms as well.

Protein kinase PKN1 associates with TRAF2 and is involved in TRAF2-NF-kappaB signaling pathway.

PKN1 is a fatty acid and Rho-activated serine/threonine protein kinase whose catalytic domain is highly homologous to protein kinase C (PKC) family. In yeast two-hybrid screening for PKN1 binding proteins, we identified tumor necrosis factor alpha (TNFalpha) receptor-associated factor 2 (TRAF2). TRAF2 is one of the major mediators of TNF receptor superfamily transducing TNF signal to various functional targets, including activation of NF-kappaB, JNK, and apoptosis. FLAG-tagged PKN1 was co-immunoprecipitated with endogenous TRAF2 from HEK293 cell lysate, and in vitro binding assay using the deletion mutants of TRAF2 showed that PKN1 directly binds to the TRAF domain of TRAF2. PKN1 has the TRAF2-binding consensus sequences PXQX (S/T) at amino acid residues 580-584 (PIQES), and P580AQ582A mutant was not co-immunoprecipitated with TRAF2. Furthermore, the reduced expression of PKN1 by RNA interference (RNAi) down-regulated TRAF2-induced NF-kappaB activation in HEK293T cells. These results suggest that PKN1 is involved in TRAF2-NF-kappaB signaling pathway.