The chromatin landscape of healthy and injured cell types in the human kidney.

There is a need to define regions of gene activation or repression that control human kidney cells in states of health, injury, and repair to understand the molecular pathogenesis of kidney disease and design therapeutic strategies. Comprehensive integration of gene expression with epigenetic features that define regulatory elements remains a significant challenge. We measure dual single nucleus RNA expression and chromatin accessibility, DNA methylation, and H3K27ac, H3K4me1, H3K4me3, and H3K27me3 histone modifications to decipher the chromatin landscape and gene regulation of the kidney in reference and adaptive injury states. We establish a spatially-anchored epigenomic atlas to define the kidney's active, silent, and regulatory accessible chromatin regions across the genome. Using this atlas, we note distinct control of adaptive injury in different epithelial cell types. A proximal tubule cell transcription factor network of ELF3, KLF6, and KLF10 regulates the transition between health and injury, while in thick ascending limb cells this transition is regulated by NR2F1. Further, combined perturbation of ELF3, KLF6, and KLF10 distinguishes two adaptive proximal tubular cell subtypes, one of which manifested a repair trajectory after knockout. This atlas will serve as a foundation to facilitate targeted cell-specific therapeutics by reprogramming gene regulatory networks.

Chronic kidney disease increases cost of care and readmission risk after shoulder arthroplasty.

BACKGROUND: Chronic kidney disease (CKD) is associated with adverse outcomes and higher costs after lower extremity arthroplasty from higher rates of infection, aseptic loosening, and transfusion and longer hospital length of stay (LOS). The purpose of this study was to compare health care utilization and 90-day encounter charges after shoulder arthroplasty (SA) in patients with and without renal disease. A secondary aim was to define the characteristics of patients with renal disease. METHODS: We conducted a retrospective cohort study of all patients who underwent primary SA from January 2015 to December 2019 by a single surgeon at a single institution. Patients without a baseline glomerular filtration rate (GFR) were excluded. We evaluated results for patients with CKD (GFR ≤59 mL/min/1.73 m2) and without CKD (GFR ≥60 mL/min/1.73 m2). Univariate regression was performed to assess the influence of CKD on health care utilization, including LOS, transfusion, and risk for emergency department (ED) revisit or readmission during the 90-day postoperative period. In addition, 90-day encounter charges, revisit charges, and ED charges for patients with CKD were compared with those for patients with normal renal function. Last, multivariable linear regression models were used to assess the effect of estimated GFR on total 90-day encounter charges. RESULTS: A total of 514 patients met the study inclusion criteria, with 125 having CKD and 389 having normal GFR. Patients with CKD were more likely to require transfusion (odds ratio: 16.2 [confidence interval: 1.9, 139.7], P = .011) despite similar intraoperative estimated blood loss (156.9 ± 132.5 mL vs. 153.8 ± 89.7 mL; P = .768). In addition, patients with CKD had longer LOS (2.8 ± 1.3 days vs. 2.3 ± 1.0 days; P < .001), had higher 90-day readmission rates (P = .001), were more likely to visit the ED within 90 days after SA (P = .018), and had higher total 90-day encounter charges ($37,769 ± $6901 vs. $35,684 ± $5312; P = .001). Each unit increase in eGFR independently reduced total encounter charges by $67 (-$132, -$2; P = .043); dialysis patients incurred higher total 90-day encounter charges compared with patients with less severe renal disease ($42,733 ± $8985 vs. $37,531 ± $6749; P = .002). Also, patients with CKD were older (73.2 ± 8.9 vs. 68.1 ± 9.4 years; P < .001); had a lower preoperative hemoglobin level (12.4 ± 1.5 g/dL vs. 13.4 ± 1.5 g/dL; P < .001), higher American Society of Anesthesiologists score (P < .001), and more preoperative comorbidities (5.9 ± 2.9 vs. 5.0 ± 3.1; P < .001); and were more likely to use opioids preoperatively (P = .043). CONCLUSION: Patients with CKD have a higher risk for blood transfusion, ED visits, and readmission after SA, with higher total 90-day encounter charges. Identifying and optimizing this patient population before surgery can reduce costs and improve outcomes, which benefits patients, physicians, institutions, and payors.

The chromatin landscape of healthy and injured cell types in the human kidney.

There is a need to define regions of gene activation or repression that control human kidney cells in states of health, injury, and repair to understand the molecular pathogenesis of kidney disease and design therapeutic strategies. However, comprehensive integration of gene expression with epigenetic features that define regulatory elements remains a significant challenge. We measured dual single nucleus RNA expression and chromatin accessibility, DNA methylation, and H3K27ac, H3K4me1, H3K4me3, and H3K27me3 histone modifications to decipher the chromatin landscape and gene regulation of the kidney in reference and adaptive injury states. We established a comprehensive and spatially-anchored epigenomic atlas to define the kidney's active, silent, and regulatory accessible chromatin regions across the genome. Using this atlas, we noted distinct control of adaptive injury in different epithelial cell types. A proximal tubule cell transcription factor network of ELF3 , KLF6 , and KLF10 regulated the transition between health and injury, while in thick ascending limb cells this transition was regulated by NR2F1 . Further, combined perturbation of ELF3 , KLF6 , and KLF10 distinguished two adaptive proximal tubular cell subtypes, one of which manifested a repair trajectory after knockout. This atlas will serve as a foundation to facilitate targeted cell-specific therapeutics by reprogramming gene regulatory networks.

Deletion of NuRD component Mta2 in nephron progenitor cells causes developmentally programmed FSGS.

Low nephron endowment at birth is a risk factor for chronic kidney disease. The prevalence of this condition is increasing due to higher survival rates of preterm infants and children with multi- organ birth defect syndromes that affect the kidney and urinary tract. We created a mouse model of congenital low nephron number due to deletion of Mta2 in nephron progenitor cells. Mta2 is a core component of the Nucleosome Remodeling and Deacetylase (NuRD) chromatin remodeling complex. These mice developed albuminuria at 4 weeks of age followed by focal segmental glomerulosclerosis (FSGS) at 8 weeks, with progressive kidney injury and fibrosis. Our studies reveal that altered mitochondrial metabolism in the post-natal period leads to accumulation of neutral lipids in glomeruli at 4 weeks of age followed by reduced mitochondrial oxygen consumption. We found that NuRD cooperated with Zbtb7a/7b to regulate a large number of metabolic genes required for fatty acid oxidation and oxidative phosphorylation. Analysis of human kidney tissue also supported a role for reduced mitochondrial lipid metabolism and ZBTB7A/7B in FSGS and CKD. We propose that an inability to meet the physiological and metabolic demands of post-natal somatic growth of the kidney promotes the transition to CKD in the setting of glomerular hypertrophy due to low nephron endowment.

Modifiable risk factors increase length of stay and 90-day cost of care after shoulder arthroplasty.

BACKGROUND: Baseline health conditions can negatively impact cost of care and risk of complications after joint replacement, necessitating additional care and incurring higher costs. Bundled payments have been used for hip and knee replacement and the Centers for Medicare & Medicaid Services (CMS) is testing bundled payments for upper extremity arthroplasty. The purpose of this study was to determine the impact of predefined modifiable risk factors (MRFs) on total encounter charges, hospital length of stay (LOS), related emergency department (ED) visits and charges, and related hospital readmissions within 90 days after shoulder arthroplasty. METHODS: We queried the electronic medical record (EPIC) for all shoulder arthroplasty cases under DRG 483 within a regional 7-hospital system between October 2015 and December 2019. Data was used to calculate mean LOS, total 90-day charges, related emergency department (ED) visits and charges, and related hospital readmissions after shoulder arthroplasty. Data for patients who had 1 or more MRFs, defined as anemia (hemoglobin < 10 g/dL), malnutrition (albumin < 3.4 g/dL), obesity (BMI > 40), uncontrolled diabetes (random glucose > 180 mg/dL or glycated hemoglobin > 8.0%), tobacco use (International Classification of Diseases, Tenth Revision, code indicating patient is a smoker), and opioid use (opioid prescription within 90 days of surgery), were evaluated as potential covariates to assess the relationship between MRFs and total encounter charges, LOS, ED visits, ED charges, and hospital readmissions. RESULTS: A total of 1317 shoulder arthroplasty patients were identified. Multivariable analysis demonstrated that anemia (+$19,847, confidence interval [CI] $15,743, $23,951; P < .001), malnutrition (+$5850, CI $3712, $7988; P < .001), and obesity (+$2762, CI $766, $4758, P = .007) independently contributed to higher charges after shoulder arthroplasty. Mean LOS was higher in patients with anemia (5.0 ± 4.0 days vs. 2.2 ± 1.6 days, P < .001), malnutrition (3.7 ± 2.8 days vs. 2.2 ± 1.5 days, P < .001), and uncontrolled diabetes (2.8 ± 2.8 days vs. 2.3 ± 1.7 days, P = .019). Univariate risk factors associated with a significant increase in total 90-day encounter charges included anemia (+$19,345, n = 37, P < .001), malnutrition (+$6971, n = 116, P < .001), obesity (+$2615, n = 184, P = .011), and uncontrolled diabetes (+$4377, n = 66, P = .011). Univariate risk for readmission within 90 days was higher in patients with malnutrition (odds ratio 3.0, CI 1.8, 4.9; P < .001). CONCLUSION: Malnutrition, obesity, and anemia contribute to significantly higher costs after shoulder arthroplasty. Medical strategies to optimize patients before shoulder arthroplasty are warranted to reduce total 90-day encounter charges, length of stay, and risk of readmission within 90 days of surgery. Optimizing patient health before shoulder surgery will positively impact outcomes and cost containment for patients, institutions, and payors after shoulder arthroplasty.

Healing rates after rotator cuff repair for patients taking either celecoxib or placebo: a double-blind randomized controlled trial.

BACKGROUND: Use of anti-inflammatory medications (NSAIDs) is an important component of multimodal pain control after orthopedic procedures to avoid opioid overutilization and abuse. However, the deleterious effects of NSAIDs on tendon healing are of particular concern in rotator cuff repair (RCR). The purpose of this study was to evaluate the effect of celecoxib or placebo on healing rates after RCR when administered in the perioperative and immediate postoperative period using MRI evaluation at one year postoperatively. A secondary aim was to determine whether clinical differences existed between patients with intact or non-intact repairs. METHODS: Patients aged ≤65 years with partial- or full-thickness rotator cuff tear (<25x25 mm) were randomized to receive celecoxib 400 mg or placebo 1 hour before the procedure and 200mg bid for 3 weeks postoperatively. All patients were treated as clinically indicated at the time of surgery and followed standard postoperative protocol. Repair integrity was evaluated with MRI using the Sugaya classification for repair integrity. Data were analyzed using multivariable logistic regression by intent to treat. RESULTS: Seventy-nine patients were enrolled; 21 were lost to follow-up, 6 did not have cuff repair, 5 were revised, and 2 declined follow-up, leaving 45 patients with one-year follow-up. Five of these patients did not complete MRI, leaving 40 patients for review. Eighteen of 20 patients (90%) who received celecoxib completed all doses of study medication as did 15 of 20 patients (75%) who received placebo. The patient groups were similar for demographics, clinical results, and healing rate. After adjusting for tear size, no statistically significant difference in healing rate was found between groups, with 10 of 20 celecoxib patients (50%) having intact repair at 1 year compared with 14 of 20 placebo patients (70%) (OR = 0.53, 95% CI: 0.14, 2.08, P = 0.35). CONCLUSION: Half of the patients who received celecoxib had an intact repair compared with 70% intact repair for patients receiving placebo. Although not statistically significant in this small study, larger studies are needed to clarify this important clinical concern. The authors do not recommend use of celecoxib for postoperative pain control after RCR.

Celecoxib significantly reduces opioid use after shoulder arthroplasty.

BACKGROUND: The opioid crisis has illuminated the risks of opioid use for pain management, with renewed interest in reducing opioid consumption after common orthopedic procedures. Anti-inflammatory medication is an important component of multimodal pain management for patients undergoing orthopedic surgery. The purpose of this study was to evaluate the effect of celecoxib on pain control and opioid use after shoulder surgery. METHODS: Patients scheduled for either total shoulder replacement (group 1) or rotator cuff repair (group 2) were candidates for the study. The exclusion criteria included allergy to celecoxib, coagulopathy, use of anticoagulants, baseline use of long-acting opioids, and a history of medical conditions such as myocardial infarction or stroke. Consenting patients were randomized by type of procedure using block randomization to receive either placebo or celecoxib 1 hour prior to the procedure and for 3 weeks postoperatively. The primary outcome measure assessed was opioid utilization as measured by morphine-equivalent dose (MED). Secondary outcome measures included pain scores at 3 and 6 weeks postoperatively. Data were analyzed using multiple linear regression. RESULTS: Of 1081 patients scheduled for either total shoulder replacement or rotator cuff repair from February 2014 to February 2018, 78 were enrolled for arthroplasty (group 1, with 39 receiving celecoxib and 39 receiving placebo) and 79 were enrolled for rotator cuff repair (group 2, with 40 receiving celecoxib and 39 receiving placebo). Compared with the placebo arm, patients prescribed celecoxib took fewer MEDs by -168 (95% confidence interval [CI], -272 to -64; P < .01) at 3 weeks in the total population and by -197.7 (95% CI, -358 to -38; P = .02) in the arthroplasty group. Similarly, at 6 weeks, total MEDs used was -199 (95% CI, -356 to -42; P < .01) in the total population and -270 (95% CI, -524 to -16; P = .04) in the arthroplasty group. No statistically significant differences in opioid consumption were found between study arms in the cuff repair group, at either 3 or 6 weeks. Of note, preoperative opioid use was statistically associated with higher levels of opioid use in the total population and group 1 at 3 and 6 weeks (P < .01 for all) but not in group 2 (P > .05 for both). CONCLUSIONS: Use of morphine equivalents was statistically significantly less at 3 and 6 weeks in patients who took celecoxib in the total population and in the arthroplasty group. Patients prescribed celecoxib for 3 weeks after shoulder surgery took less opioid medication for pain at 3 and 6 weeks. Multimodal pain control using celecoxib is an effective way to reduce postoperative opioid use in shoulder arthroplasty patients. Preoperative opioid use is associated with higher levels of opioid use after shoulder arthroplasty.

The core SWI/SNF catalytic subunit Brg1 regulates nephron progenitor cell proliferation and differentiation.

Chromatin-remodeling complexes play critical roles in establishing gene expression patterns in response to developmental signals. How these epigenetic regulators determine the fate of progenitor cells during development of specific organs is not well understood. We found that genetic deletion of Brg1 (Smarca4), the core enzymatic protein in SWI/SNF, in nephron progenitor cells leads to severe renal hypoplasia. Nephron progenitor cells were depleted in Six2-Cre, Brg1flx/flx mice due to reduced cell proliferation. This defect in self-renewal, together with impaired differentiation resulted in a profound nephron deficit in Brg1 mutant kidneys. Sall1, a transcription factor that is required for expansion and maintenance of nephron progenitors, associates with SWI/SNF. Brg1 and Sall1 bind promoters of many progenitor cell genes and regulate expression of key targets that promote their proliferation.

Pharmacologic inhibition of RGD-binding integrins ameliorates fibrosis and improves function following kidney injury.

Fibrosis is a final common pathway for many causes of progressive chronic kidney disease (CKD). Arginine-glycine-aspartic acid (RGD)-binding integrins are important mediators of the pro-fibrotic response by activating latent TGF-ß at sites of injury and by providing myofibroblasts information about the composition and stiffness of the extracellular matrix. Therefore, blockade of RGD-binding integrins may have therapeutic potential for CKD. To test this idea, we used small-molecule peptidomimetics that potently inhibit a subset of RGD-binding integrins in a murine model of kidney fibrosis. Acute kidney injury leading to fibrosis was induced by administration of aristolochic acid. Continuous subcutaneous administration of CWHM-12, an RGD integrin antagonist, for 28 days improved kidney function as measured by serum creatinine. CWHM-12 significantly reduced Collagen 1 (Col1a1) mRNA expression and scar collagen deposition in the kidney. Protein and gene expression markers of activated myofibroblasts, a major source of extracellular matrix deposition in kidney fibrosis, were diminished by treatment. RNA sequencing revealed that inhibition of RGD integrins influenced multiple pathways that determine the outcome of the response to injury and of repair processes. A second RGD integrin antagonist, CWHM-680, administered once daily by oral gavage was also effective in ameliorating fibrosis. We conclude that targeting RGD integrins with such small-molecule antagonists is a promising therapeutic approach in fibrotic kidney disease.

Rotator Cuff Repair With Knotless Technique Is Quicker and More Cost-Effective Than Knotted Technique.

PURPOSE: To determine the cost-effectiveness of knotted (KT) versus knotless (KL) methods for rotator cuff surgical repair and to assess differences in patients' outcomes. METHODS: We retrospectively identified all patients who underwent arthroscopic rotator cuff repair at 1 institution by 1 surgeon over 2 6-month periods of time (KT technique from August 1, 2013, through January 31, 2014; and KL technique from December 1, 2014, through May 31, 2015) to calculate the direct and indirect costs associated with arthroscopic KT or KL suture bridge rotator cuff repair. Patient demographics, number of anchors used, tendons repaired, procedure time, operative time, and clinical results were also evaluated. We used univariate generalized linear models with a Gaussian distribution for assessment scores and total and implant cost data. RESULTS: We identified 87 patients for inclusion during the 2 time frames (35 KT, 54 KL). After excluding patients for tear size < 4 cm2 (n = 42), ≤ 3 anchors (n = 5), revision surgery (n = 1), and those in whom additional procedures were performed (n = 2), 37 eligible subjects remained (nKT = 15, nKL = 22). Median implant costs were statistically significantly higher in the KL group than in the KT group (MKL = $2,127, MKT = $1,520, ß = 413.7, 95% CI: 242.8, 584.6, P < .01), and more anchors were used in the KL group, with KT requiring a median of 4 anchors (IQR: 4, 5) and KL requiring a median of 5 anchors (IQR: 5, 5, P = .02). Procedure time was cut in half with KL repair (estimated 43.5 minutes) versus KT repair (80 minutes) (ß = 0.5, 95% CI: 0.4, 0.6, P < .001). Operating room time also was reduced by approximately 40% (79.5 minutes for KL; 121 minutes for KT [ß = 0.6, CI: 0.6, 0.7, P < .001]). Once operating room costs were considered, median costs were found to be significantly lower in the KL group (MKL = $3788.40, MKT = $4262.90, ß = -492.1, 95% CI: -840.0, -144.1, P < .01). No statistically significant differences were found between groups in mean preoperative, postoperative or postpreoperative differences in the visual analog scale, Simple Shoulder Test, American Shoulder and Elbow Surgeons, or University of California at Los Angeles scores (P > 0.05 for all). CONCLUSIONS: Despite using more anchors and incurring higher implant costs, the KL technique for rotator cuff repair required less surgical procedure time and cost less overall than the KT technique and resulted in equivalent clinical results. LEVEL OF EVIDENCE: Level IV Economic and Decision Analyses.

Estimated blood loss and anemia predict transfusion after total shoulder arthroplasty: a retrospective cohort study.

BACKGROUND: Reported blood transfusion rates after total shoulder arthroplasty (TSA) range from 4.5% to 43%, and reported risk factors include race, female sex, prosthesis type (reverse), revision, age, anemia, low preoperative hemoglobin, and number of comorbidities. The purpose of this study was to develop a predictive model for transfusion in anatomic/hemi and reverse shoulder arthroplasty patients and to estimate the transfusion rate in a community hospital setting. METHODS: A retrospective cohort of 265 shoulder arthroplasties (79 anatomic, 182 reverse, and 4 hemiarthroplasties) performed consecutively by 1 surgeon at 1 institution from May 2013 to May 2016 was assembled. Two patients were excluded for insufficient data, leaving 263 patients for analysis. Sensitivity, specificity, area under the curve, and cut points using estimated blood loss (EBL), history of anemia, and preoperative hemoglobin level were calculated, based on a logistic regression model. RESULTS: The overall transfusion rate was 2.3% (6/265). Higher EBL (P = .003), lower preoperative hemoglobin level (P = .030), and history of anemia (P = .088) were predictive of transfusion with a sensitivity of 80.0% and a specificity of 99.6%. In this cohort, patients with a history of anemia had transfusion risk when an EBL of ≥300 mL was combined with a preoperative hemoglobin level <10.9, resulting in a sensitivity of 1.0 and a specificity of 0.96. Factors associated with transfusion in univariate models included arthroplasty for fracture (P < .001), cemented stem (P < .001), length of stay (P < .001), EBL (P < .001), operative time (P < .001), and preoperative hemoglobin (P = .004) and hematocrit levels (P = .004). CONCLUSION: Patients with a history of anemia, a preoperative hemoglobin level <10.9, and an intraoperative EBL ≥300 mL are at high risk for transfusion after TSA.

Building Meaningful Patient Engagement in Research: Case Study From ADVANCE Clinical Data Research Network.

BACKGROUND: Strategies to engage patients to improve and enhance research and clinical care are increasingly being implemented in the United States, yet little is known about best practices for or the impacts of meaningful patient engagement. OBJECTIVE: We describe and reflect on our patient stakeholder groups, engagement framework, experiences, and lessons learned in engaging patients in research, from generating proposal ideas to disseminating findings. SETTING: The ADVANCE (Accelerating Data Value Across a National Community Health Center Network) clinical data research network is the nation's largest clinical dataset on the safety net, with outpatient clinical data from 122 health systems (1109 clinics) in 23 states. RESULTS: Patients stakeholders codeveloped the ADVANCE engagement framework and its implementation in partnership with network leaders. In phase I of ADVANCE, patients were involved with designing studies (input on primary outcome measures and methods) and usability testing (of the patient portal). In phase II, the network is prioritizing research training, dissemination opportunities, an "ambassador" program to pair more experienced patient stakeholders with those less experienced, and evaluation of engagement activities and impacts. DISCUSSION: The ADVANCE framework for patient engagement has successfully involved a diverse group of patients in the design, implementation, and interpretation of comparative effectiveness research. Our experience and framework can be used by other organizations and research networks to support patient engagement activities.

Disparate levels of beta-catenin activity determine nephron progenitor cell fate.

Formation of a functional kidney depends on the balance between renewal and differentiation of nephron progenitors. Failure to sustain this balance can lead to kidney failure or stem cell tumors. For nearly 60 years, we have known that signals from an epithelial structure known as the ureteric bud were essential for maintaining this balance. More recently it was discovered that one molecule, Wnt9b, was necessary for both renewal and differentiation of the nephron progenitor cells. How one ligand signaling through one transcription factor promoted two seemingly contradictory cellular processes was unclear. In this study, we show that Wnt9b/beta-catenin signaling alone is sufficient to promote both renewal and differentiation. Moreover, we show that discrete levels of beta-catenin can promote these two disparate fates, with low levels fostering progenitor renewal and high levels driving differentiation. These results provide insight into how Wnt9b regulates distinct target genes that balance nephron progenitor renewal and differentiation.

SALL1 functions as a tumor suppressor in breast cancer by regulating cancer cell senescence and metastasis through the NuRD complex.

BACKGROUND: SALL1 is a multi-zinc finger transcription factor that regulates organogenesis and stem cell development, but the role of SALL1 in tumor biology and tumorigenesis remains largely unknown. METHODS: We analyzed SALL1 expression levels in human and murine breast cancer cells as well as cancer tissues from different types of breast cancer patients. Using both in vitro co-culture system and in vivo breast tumor models, we investigated how SALL1 expression in breast cancer cells affects tumor cell growth and proliferation, metastasis, and cell fate. Using the gain-of function and loss-of-function strategies, we dissected the molecular mechanism responsible for SALL1 tumor suppressor functions. RESULTS: We demonstrated that SALL1 functions as a tumor suppressor in breast cancer, which is significantly down-regulated in the basal like breast cancer and in estrogen receptor (ER), progesterone receptor (PR) and epidermal growth factor receptor 2 (HER2) triple negative breast cancer patients. SALL1 expression in human and murine breast cancer cells inhibited cancer cell growth and proliferation, metastasis, and promoted cell cycle arrest. Knockdown of SALL1 in breast cancer cells promoted cancer cell growth, proliferation, and colony formation. Our studies revealed that tumor suppression was mediated by recruitment of the Nucleosome Remodeling and Deacetylase (NuRD) complex by SALL1, which promoted cancer cell senescence. We further demonstrated that the mechanism of inhibition of breast cancer cell growth and invasion by SALL1-NuRD depends on the p38 MAPK, ERK1/2, and mTOR signaling pathways. CONCLUSION: Our studies indicate that the developmental control gene SALL1 plays a critical role in tumor suppression by recruiting the NuRD complex and thereby inducing cell senescence in breast cancer cells.

SALL1 expression in acute myeloid leukemia.

Similar signaling pathways could operate in both normal hematopoietic stem and progenitor cells (HSPCs) and leukemia stem cells (LSCs). Thus, targeting LSCs signaling without substantial toxicities to normal HSPCs remains challenging. SALL1, is a member of the transcriptional network that regulates stem cell pluripotency, and lacks significant expression in most adult tissues, including normal bone marrow (NBM). We examined the expression and functional characterization of SALL1 in NBM and in acute myeloid leukemia (AML) using in vitro and in vivo assays. We showed that SALL1 is expressed preferentially in LSCs- enriched CD34+CD38- cell subpopulation but not in NBM. SALL1 inhibition resulted in decreased cellular proliferation and in inferior AML engraftment in NSG mice and it was also associated with upregulation of PTEN and downregulation of m-TOR, ß-catenin, and NF-қB expression. These findings suggest that SALL1 inhibition interrupts leukemogenesis. Further studies to validate SALL1 as a potential biomarker for minimal residual disease (MRD) and to determine SALL1's role in prognostication are ongoing. Additionally, pre-clinical evaluation of SALL1 as a therapeutic target in AML is warranted.

A Sall1-NuRD interaction regulates multipotent nephron progenitors and is required for loop of Henle formation.

The formation of the proper number of nephrons requires a tightly regulated balance between renal progenitor cell self-renewal and differentiation. The molecular pathways that regulate the transition from renal progenitor to renal vesicle are not well understood. Here, we show that Sall1interacts with the nucleosome remodeling and deacetylase complex (NuRD) to inhibit premature differentiation of nephron progenitor cells. Disruption of Sall1-NuRD in vivo in knock-in mice (ΔSRM) resulted in accelerated differentiation of nephron progenitors and bilateral renal hypoplasia. Transcriptional profiling of mutant kidneys revealed a striking pattern in which genes of the glomerular and proximal tubule lineages were either unchanged or upregulated, and those in the loop of Henle and distal tubule lineages were downregulated. These global changes in gene expression were accompanied by a significant decrease in THP-, NKCC2- and AQP1-positive loop of Henle nephron segments in mutant ΔSRM kidneys. These findings highlight an important function of Sall1-NuRD interaction in the regulation of Six2-positive multipotent renal progenitor cells and formation of the loop of Henle.

Lessons Learned from Developing a Patient Engagement Panel: An OCHIN Report.

There is renewed interest in patient engagement in clinical and research settings, creating a need for documenting and publishing lessons learned from efforts to meaningfully engage patients. This article describes early lessons learned from the development of OCHIN's Patient Engagement Panel (PEP). OCHIN supports a national network of more than 300 community health centers (CHCs) and other primary care settings that serve over 1.5 million patients annually across nearly 20 states. The PEP was conceived in 2009 to harness the CHC tradition of patient engagement in this new era of patient-centered outcomes research and to ensure that patients were engaged throughout the life cycle of our research projects, from conception to dissemination. Developed by clinicians and researchers within our practice-based research network, recruitment of patients to serve as PEP members began in early 2012. The PEP currently has a membership of 18 patients from 3 states. Over the past 24 months, the PEP has been involved with 12 projects. We describe developing the PEP and challenges and lessons learned (eg, recruitment, funding model, creating value for patient partners, compensation). These lessons learned are relevant not only for research but also for patient engagement in quality improvement efforts and other clinical initiatives.

A mouse model of Townes-Brocks syndrome expressing a truncated mutant Sall1 protein is protected from acute kidney injury.

It has been postulated that developmental pathways are reutilized during repair and regeneration after injury, but functional analysis of many genes required for kidney formation has not been performed in the adult organ. Mutations in SALL1 cause Townes-Brocks syndrome (TBS) and nonsyndromic congenital anomalies of the kidney and urinary tract, both of which lead to childhood kidney failure. Sall1 is a transcriptional regulator that is expressed in renal progenitor cells and developing nephrons in the embryo. However, its role in the adult kidney has not been investigated. Using a mouse model of TBS (Sall1TBS), we investigated the role of Sall1 in response to acute kidney injury. Our studies revealed that Sall1 is expressed in terminally differentiated renal epithelia, including the S3 segment of the proximal tubule, in the mature kidney. Sall1TBS mice exhibited significant protection from ischemia-reperfusion injury and aristolochic acid-induced nephrotoxicity. This protection from acute injury is seen despite the presence of slowly progressive chronic kidney disease in Sall1TBS mice. Mice containing null alleles of Sall1 are not protected from acute kidney injury, indicating that expression of a truncated mutant protein from the Sall1TBS allele, while causative of congenital anomalies, protects the adult kidney from injury. Our studies further revealed that basal levels of the preconditioning factor heme oxygenase-1 are elevated in Sall1TBS kidneys, suggesting a mechanism for the relative resistance to injury in this model. Together, these studies establish a functional role for Sall1 in the response of the adult kidney to acute injury.

Sall1 balances self-renewal and differentiation of renal progenitor cells.

The formation of the proper number of functional nephrons requires a delicate balance between renal progenitor cell self-renewal and differentiation. The molecular factors that regulate the dramatic expansion of the progenitor cell pool and differentiation of these cells into nephron precursor structures (renal vesicles) are not well understood. Here we show that Sall1, a nuclear transcription factor, is required to maintain the stemness of nephron progenitor cells. Transcriptional profiling of Sall1 mutant cells revealed a striking pattern, marked by the reduction of progenitor genes and amplified expression of renal vesicle differentiation genes. These global changes in gene expression were accompanied by ectopic differentiation at E12.5 and depletion of Six2+Cited1+ cap mesenchyme progenitor cells. These findings highlight a novel role for Sall1 in maintaining the stemness of the progenitor cell pool by restraining their differentiation into renal vesicles.