Citations

Abstract Cytotoxic T lymphocytes (CTL) are indispensable in anti-tumor immunity. Although CTLs are prone to exhaustion in patients with advanced cancer, T cell resiliency explains the presence of tumor-reactive CTLs that are less exhausted, capable of cytolytic function, expansion, and rebound in response to immunotherapy to reject metastatic malignancies. However, the features of resilient T cells have not been clearly defined. In this report, we demonstrate that peripheral CX3CR1+ CD8+ T cells with low mitochondrial membrane potential rebounded CTL function quickly after radiation therapy in patients with large tumor burden portraying their functional resiliency. Furthermore, CX3CR1+ CD8+ T cell with low, but not high, mitochondrial membrane potential are highly cytotoxic, accumulate less reactive oxygen species (ROS), and express more Malic enzyme 1 (ME1). ME1 overexpression increases ATP production in a glycolysis-independent manner while concurrently curtailing excessive ROS in activated CD8+ T cells; and expands CX3CR1+NKG7+ effector CD8+ T cells with enhanced cytotoxicity. Importantly, transfection of ME1 mRNA promotes tumoricidal activity in CD8+ T cells from patients with advanced cancers. Our study reveals a mechanism used by CTLs to balance excessive ROS via ME1 to maintain a metabolic and functional resiliency. Modification of ME1 expression in CTLs may be a novel method to improve the efficacy of cancer immunotherapy by preventing T cell exhaustion. Supported by grants from Mayo Clinic Foundation and NIH (R01CA 256927-2)

Abstract Although immune checkpoint blockade that targets the PD-L1 has revolutionized the treatment of human cancers, only a small proportion of patients positively respond to this form of treatment. A limitation of these therapies is that they only target and inhibit PD-L1’s extracellular function, which is to bind its receptor on PD-1 on T cells and inhibit T cell cytotoxicity. Recent discoveries have shown that PD-L1 expressed on tumor cells can signal intrinsically and independently of PD-1 ligation to promote tumor cell survival. Besides tumor cells, host myeloid cells have been shown to have high expression of PD-L1, therefore contributing to the immunosuppressive nature of the tumor. However, PD-L1 intrinsic signaling in human myeloid cells has not been studied. Therefore, the purpose of our work is to determine the intrinsic functions of PD-L1 in myeloid cells and how this impacts anti-tumor immunity. To study this, we used a novel PD-L1 antibody (H1A) that does not block PD-L1’s binding with PD-1, but directs PD-L1 for degradation, thereby decreasing total PD-L1 expression. Additionally, we developed a chimeric mouse model in which the murine PD-1/PD-L1 has been replaced with the human version. This allows us to evaluate PD-L1’s intrinsic function in vivo. In our preliminary studies, the degradation of PD-L1 in human monocytes led to increased chemokine release as well as increased conversion of effector T cells. Additionally, H1A treatment of tumor-bearing mice led to lower tumor burden in a CD8 T cell dependent manner. Based on these results, PD-L1 intrinsic signaling has the potential to regulate the immune-stimulatory response of monocytes, thereby limiting effector T cell responses against cancer. Supported by grants from NIH (R0192389) and Mayo Clinic graduate school of biomedical sciences

Abstract Though anti-PD-1/PD-L1 immune checkpoint blockade therapy has demonstrated robust anti-tumor immunity in human patients with advanced cancers such as melanoma, only a fraction of patients achieved such durable anti-tumor responses. Among all the non-responders, some patients responded initially but developed resistance to the therapy in the later treatments. This reflects an urgent need to understand the role of PD-1 signals in CD8+ T cells at priming and at effector stages during tumor development for the benefit of immunotherapy. The controversy of rapid tumor progression in PD-1 conditional knockout in regulatory T cells and tumor regression in PD-1 targeted deletion in regulatory T cells indicated germline PD-1 knockout mice might not be sophisticated enough to study the role of PD-1 in CD8+ T cells during tumor development. Thus, we produced a CD8 T cell-specific PD-1 knockout mouse model (CD8 E8ICre-PD-1fl/fl, also called CD8-PD-1 cKO mice) in which PD-1 is deleted in CD8+ T cells in the peripheral tissues. When CD8-PD-1 cKO mice were challenged with B16-OVA mouse melanoma cells, we found a delayed tumor growth and prolonged survival of CD8-PD-1 cKO compared to control mice. However, after 20 days of tumor challenge, the delayed tumor growth rebound in CD8-PD-1 cKO mice. In an OVA antigen immunization model, we found increased effector cells and tissue resident cells in the spleen of CD8-PD-1 cKO mice compared with control mice on day 7 after immunization. Taken together, our results suggest that PD-1 may restrain the expansion of effector T cells that contribute to the early phase of tumor control, but the augmented effector T cell response may cause an attrition of memory T cell pool that will be needed for long term protection. R01CA256927

Background: Contrast-induced encephalopathy (CIE) is an infrequent but serious neurological condition that occurs shortly after the administration of contrast during endovascular and angiography procedures. Patients suffering from chronic kidney disease (CKD) or end-stage kidney disease (ESKD) are considered to be at a higher risk of contrast medium neurotoxicity, due to the delayed elimination of the contrast medium. However, the occurrence and characteristics of CIE in CKD/ESKD patients have not been extensively investigated. Methods: We conducted a comprehensive literature search, utilizing databases such as MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and the Cochrane Database of Systematic Reviews, up to September 2022. The purpose was to identify documented cases of CIE among patients with CKD or ESKD. Employing a random-effects model, we calculated the pooled incidence and odds ratio (OR) of CIE in CKD/ESKD patients. Results: Our search yielded a total of eleven articles, comprising nine case reports and two observational studies. Among these studies, 2 CKD patients and 12 ESKD patients with CIE were identified. The majority of the CKD/ESKD patients with CIE (93%) had undergone intra-arterial contrast media and/or endovascular procedures to diagnose acute cerebrovascular disease, coronary artery disease, and peripheral artery disease. The male-to-female ratio was 64%, and the median age was 63 years (with an interquartile range of 55 to 68 years). In the two observational studies, the incidence of CIE was found to be 6.8% in CKD patients and 37.5% in ESKD patients, resulting in a pooled incidence of 16.4% (95% CI, 2.4%–60.7%) among the CKD/ESKD patients. Notably, CKD and ESKD were significantly associated with an increased risk of CIE, with ORs of 5.77 (95% CI, 1.37–24.3) and 223.5 (95% CI, 30.44–1641.01), respectively. The overall pooled OR for CIE in CKD/ESKD patients was 32.9 (95% CI, 0.89–1226.44). Although dialysis prior to contrast exposure did not prevent CIE, approximately 92% of CIE cases experienced recovery after undergoing dialysis following contrast exposure. However, the effectiveness of dialysis on CIE recovery remained uncertain, as there was no control group for comparison. Conclusions: In summary, our study indicates an association between CIE and CKD/ESKD. While patients with CIE showed signs of recovery after dialysis, further investigations are necessary, especially considering the lack of a control group, which made the effects of dialysis on CIE recovery uncertain.

Limited data are available on the utilization of sodium thiosulfate (STS) treatment for calciphylaxis in peritoneal dialysis (PD) patients, while it is well-studied in hemodialysis (HD) patients. A systematic literature search was conducted using Ovid MEDLINE, EBM Reviews—Cochrane Central Register of Controlled Trials, and EBM Reviews—Cochrane Database of Systematic Reviews to identify reported cases of PD patients with calciphylaxis who received STS. The search covered the inception of the databases through August 2022. Across 19 articles, this review identified 30 PD patients with calciphylaxis who received STS. These included 15 case reports, 2 case series, and 2 cohort studies. The administration routes and doses varied depending on the study. For intravenous (IV) administration (n = 18), STS doses ranged from 3.2 g twice daily to 25 g three times weekly for 5 weeks to 8 months. Outcomes included 44% of patients experiencing successful wound healing, 6% discontinuing STS due to adverse effects, 67% transitioning to HD, and 50% dying from calciphylaxis complications. For intraperitoneal (IP) administration (n = 5), STS doses ranged from 12.5 to 25 g three to four times weekly for 12 h to 3 months. Results showed 80% of patients achieving successful wound healing, 80% discontinuing STS due to adverse effects, 40% transitioning to HD, and 20% dying from IP STS-related chemical peritonitis. In cases where patients switched from IV to IP STS (n = 3), doses ranged from 12.5 to 25 g two to three times weekly for 2.5 to 5 months. Among them, 67% experienced successful wound healing, while 33% died from sepsis. Two cases utilized oral STS at a dose of 1500 mg twice daily for 6 and 11 months, resulting in successful wound healing without adverse effects or need for HD. However, one patient (50%) died due to small bowel obstruction. This systematic review provides an overview of STS treatment for PD patients with calciphylaxis. Although successful treatment cases exist, adverse effects were significant. Further research, including larger clinical studies and pharmacokinetic data, is necessary to establish the optimal route, dose, and efficacy of STS in PD patients.

Clinical outcomes of deceased donor kidney transplants coming from diabetic donors currently remain inconsistent, possibly due to high heterogeneities in this population. Our study aimed to cluster recipients of diabetic deceased donor kidney transplants using an unsupervised machine learning approach in order to identify subgroups with high risk of inferior outcomes and potential variables associated with these outcomes. Consensus cluster analysis was performed based on recipient-, donor-, and transplant-related characteristics in 7876 recipients of diabetic deceased donor kidney transplants from 2010 to 2019 in the OPTN/UNOS database. We determined the important characteristics of each assigned cluster and compared the post-transplant outcomes between the clusters. Consensus cluster analysis identified three clinically distinct clusters. Recipients in cluster 1 (n = 2903) were characterized by oldest age (64 ± 8 years), highest rate of comorbid diabetes mellitus (55%). They were more likely to receive kidney allografts from donors that were older (58 ± 6.3 years), had hypertension (89%), met expanded criteria donor (ECD) status (78%), had a high rate of cerebrovascular death (63%), and carried a high kidney donor profile index (KDPI). Recipients in cluster 2 (n = 687) were younger (49 ± 13 years) and all were re-transplant patients with higher panel reactive antibodies (PRA) (88 [IQR 46, 98]) who received kidneys from younger (44 ± 11 years), non-ECD deceased donors (88%) with low numbers of HLA mismatch (4 [IQR 2, 5]). The cluster 3 cohort was characterized by first-time kidney transplant recipients (100%) who received kidney allografts from younger (42 ± 11 years), non-ECD deceased donors (98%). Compared to cluster 3, cluster 1 had higher incidence of primary non-function, delayed graft function, patient death and death-censored graft failure, whereas cluster 2 had higher incidence of delayed graft function and death-censored graft failure but comparable primary non-function and patient death. An unsupervised machine learning approach characterized diabetic donor kidney transplant patients into three clinically distinct clusters with differing outcomes. Our data highlight opportunities to improve utilization of high KDPI kidneys coming from diabetic donors in recipients with survival-limiting comorbidities such as those observed in cluster 1.

The EGFR-RAS-ERK pathway is one of the most important signaling cascades in cell survival, growth, and proliferation. Aberrant activation of this pathway is a common mechanism in various cancers. Here, we report that CDK2 is a novel regulator of the ERK pathway via USP37 deubiquitinase (DUB). Mechanistically, CDK2 phosphorylates USP37, which is required for USP37 DUB activity. Further, USP37 deubiquitinates and stabilizes ERK1/2, thereby enhancing cancer cell proliferation. Thus, CDK2 is able to promote cell proliferation by activating USP37 and, in turn, stabilizing ERK1/2. Importantly, combined CDK1/2 and EGFR inhibitors have a synergetic anticancer effect through the downregulation of ERK1/2 stability and activity. Indeed, our patient-derived xenograft (PDX) results suggest that targeting both ERK1/2 stability and activity kills cancer cells more efficiently even at lower doses of these two inhibitors, which may reduce their associated side effects and indicate a potential new combination strategy for cancer therapy.

Zebrafish is a well-established model organism for cardiovascular disease studies in which one of the most popular tasks is to assess cardiac functions from the heart beating echo-videos. However, current techniques are often time-consuming and error-prone, making them unsuitable for large-scale analysis. To address this problem, we designed a method to automatically evaluate the ejection fraction of zebrafish from heart echo-videos using a deep-learning model architecture. Our model achieved a validation Dice coefficient of 0.967 and an IoU score of 0.937 which attest to its high accuracy. Our test findings revealed an error rate ranging from 0.11% to 37.05%, with an average error rate of 9.83%. This method is widely applicable in any laboratory setting and can be combined with binary recordings to optimize the efficacy and consistency of large-scale video analysis. By facilitating the precise quantification and monitoring of cardiac function in zebrafish, our approach outperforms traditional methods, substantially reducing the time and effort required for data analysis. The advantages of our method make it a promising tool for cardiovascular research using zebrafish.

Abstract Background and Aims Individuals who are most susceptible to developing PTLD are those who are EBV-negative and receive organs from EBV-positive donors (EBV R-/D+). The evidence regarding the connection between ATG induction therapy and PTLD is inconsistent. No studies have specifically examined the relationship between ATG use and PTLD in subgroups of EBV-negative transplant recipients (EBV R-). Using the UNOS database, we studied the association between the use of induction agents and PTLD in EBV R- patients. Method We analyzed data from 2007 to 2022 of EBV R- patients who underwent their first kidney-only transplant and excluded those who received induction agents other than ATG, basiliximab, or alemtuzumab. We used logistic regression to evaluate the association between induction agents and PTLD. Results Of 20,531 recipients, 50.7% received ATG, 19.13% received basiliximab, 13.42% received alemtuzumab, and 16.75% received no induction. The overall PTLD incidence was 2.14%. ATG recipients had higher rates of deceased donor transplants, higher degree of HLA mismatch, longer dialysis vintage, and were less likely to be white, compared to non-ATG recipients. Multivariate analysis showed ATG recipients had a higher risk of PTLD compared to non-ATG (odds ratio = 1.47, p<0.001). After excluding recipients who did not receive induction, ATG remained a significant independent risk factor for PTLD when compared to recipients who received either basiliximab or alemtuzumab (odds ratio = 1.35, p = 0.007). There was no statistically significant difference in PTLD risk among patients treated with basiliximab, alemtuzumab, or no induction (refer to Table 1). Conclusion The use of ATG induction in EBV-negative kidney transplant recipients is associated with a higher risk of PTLD compared to basiliximab, alemtuzumab, and no induction. The risk of PTLD should be considered when choosing induction therapy for this patient population.