TRMT10A dysfunction perturbs codon translation of initiator methionine and glutamine and impairs brain functions in mice.

In higher eukaryotes, tRNA methyltransferase 10A (TRMT10A) is responsible for N1-methylguanosine modification at position nine of various cytoplasmic tRNAs. Pathogenic mutations in TRMT10A cause intellectual disability, microcephaly, diabetes, and short stature in humans, and generate cytotoxic tRNA fragments in cultured cells; however, it is not clear how TRMT10A supports codon translation or brain functions. Here, we generated Trmt10a null mice and showed that tRNAGln(CUG) and initiator methionine tRNA levels were universally decreased in various tissues; the same was true in a human cell line lacking TRMT10A. Ribosome profiling of mouse brain revealed that dysfunction of TRMT10A causes ribosome slowdown at the Gln(CAG) codon and increases translation of Atf4 due to higher frequency of leaky scanning of its upstream open reading frames. Broadly speaking, translation of a subset of mRNAs, especially those for neuronal structures, is perturbed in the mutant brain. Despite not showing discernable defects in the pancreas, liver, or kidney, Trmt10a null mice showed lower body weight and smaller hippocampal postsynaptic densities, which is associated with defective synaptic plasticity and memory. Taken together, our study provides mechanistic insight into the roles of TRMT10A in the brain, and exemplifies the importance of universal tRNA modification during translation of specific codons.

Real-world data on induction therapy in patients with transplant-ineligible newly diagnosed multiple myeloma: retrospective analysis of 598 cases from Kansai Myeloma Forum.

To investigate the real-world clinical outcomes and management of novel drug-containing therapies for newly diagnosed multiple myeloma (MM) patients, we retrospectively analyzed data on the first-line treatment for newly diagnosed transplant-ineligible MM patients from Kansai Myeloma Forum, a registry network in Japan. A total of 598 patients treated with novel drugs between March 2007 and February 2018 were analyzed. Regimens used were VD (n = 305), Rd (n = 103), VMP (n = 97), VCD (n = 71), and VRd (n = 22). Younger patients tended to receive VRd or VCD, whereas the regimen with the highest median patient age was Rd. More than three-quarters of patients in the Rd group received a reduced dose of lenalidomide. The Rd and VRd groups had a relatively high incidence of infection and skin complications, and the VMP group had the highest incidence of peripheral neuropathy. Overall response rate did not differ significantly between regimens. Multivariate analysis in all patients revealed several poor prognostic factors, such as poor performance status. Novel drug-containing regimens for newly diagnosed MM showed a durable response with manageable AEs in the real-world setting.

Artificial induction of circadian rhythm by combining exogenous BMAL1 expression and polycomb repressive complex 2 inhibition in human induced pluripotent stem cells.

Understanding the physiology of human-induced pluripotent stem cells (iPSCs) is necessary for directed differentiation, mimicking embryonic development, and regenerative medicine applications. Pluripotent stem cells (PSCs) exhibit unique abilities such as self-renewal and pluripotency, but they lack some functions that are associated with normal somatic cells. One such function is the circadian oscillation of clock genes; however, whether or not PSCs demonstrate this capability remains unclear. In this study, the reason why circadian rhythm does not oscillate in human iPSCs was examined. This phenomenon may be due to the transcriptional repression of clock genes resulting from the hypermethylation of histone H3 at lysine 27 (H3K27), or it may be due to the low levels of brain and muscle ARNT-like 1 (BMAL1) protein. Therefore, BMAL1-overexpressing cells were generated and pre-treated with GSK126, an inhibitor of enhancer of zest homologue 2 (EZH2), which is a methyltransferase of H3K27 and a component of polycomb repressive complex 2. Consequently, a significant circadian rhythm following endogenous BMAL1, period 2 (PER2), and other clock gene expression was induced by these two factors, suggesting a candidate mechanism for the lack of rhythmicity of clock gene expression in iPSCs.

Efficacy of elotuzumab for multiple myeloma in reference to lymphocyte counts and kappa/lambda ratio or B2 microglobulin.

Novel therapeutic drugs have dramatically improved the overall survival of patients with multiple myeloma. We sought to identify the characteristics of patients likely to exhibit a durable response to one such drug, elotuzumab, by analyzing a real-world database in Japan. We analyzed 179 patients who underwent 201 elotuzumab treatments. The median time to next treatment (TTNT) with the 95% confidence interval was 6.29 months (5.18-9.20) in this cohort. Univariate analysis showed that patients with any of the following had longer TTNT: no high risk cytogenic abnormalities, more white blood cells, more lymphocytes, non-deviated κ/λ ratio, lower ß2 microglobulin levels (B2MG), fewer prior drug regimens, no prior daratumumab use and better response after elotuzumab treatment. A multivariate analysis showed that TTNT was longer in patients with more lymphocytes (≥ 1400/µL), non-deviated κ/λ ratio (0.1-10), lower B2MG (< 5.5 mg/L) and no prior daratumumab use. We proposed a simple scoring system to predict the durability of the elotuzumab treatment effect by classifying the patients into three categories based on their lymphocyte counts (0 points for ≥ 1400/µL and 1 point for < 1400/µL) and κ/λ ratio (0 points for 0.1-10 and 1 point for < 0.1 or ≥ 10) or B2MG (0 points for < 5.5 mg/L and 1 point for ≥ 5.5 mg/L). The patients with a score of 0 showed significantly longer TTNT (p < 0.001) and better survival (p < 0.001) compared to those with a score of 1 or 2. Prospective cohort studies of elotuzumab treatment may be needed to validate the usefulness of our new scoring system.

Monocyte or white blood cell counts and ß2 microglobulin predict the durable efficacy of daratumumab with lenalidomide.

Background: Daratumumab is one of the most widely used treatments for relapsed/refractory multiple myeloma (MM) patients. However, not all patients achieve a lasting therapeutic response with daratumumab. Objectives: We hypothesized that a durable response to daratumumab could be predicted by the balance between the MM tumor burden and host immune status. Design: We conducted a retrospective study using the real-world data in the Kansai Myeloma Forum (KMF) database. Methods: We retrospectively analyzed 324 relapsed/refractory MM patients who were treated with daratumumab in the KMF database. Results: In this study, 196 patients were treated with daratumumab, lenalidomide, and dexamethasone (DLd) regimen and 128 patients were treated with daratumumab, bortezomib, and dexamethasone (DBd) regimen. The median age at treatment, number of prior treatment regimens and time-to-next-treatment (TTNT) were 68, 4 and 8.02 months, respectively. A multivariate analysis showed that the TTNT under the DLd regimen was longer with either higher monocyte counts (analysis 1), higher white blood cell (WBC) counts (analysis 2), lower ß2 microglobulin (B2MG < 5.5 mg/L) or fewer prior regimens (<4). No parameters were correlated with TTNT under the DBd regimen. Conclusion: We propose a simple scoring model to predict a durable effect of the DLd regimen by classifying patients into three categories based on either monocyte counts (0 points for ⩾200/µl; 1 point for <200/µl) or WBC counts (0 points for ⩾3500/µl; 1 point for <3500/µl) plus B2MG (0 points for <5.5 mg/L; 1 point for ⩾5.5 mg/L). Patients with a score of 0 showed significantly longer TTNT and significantly better survival compared to those with a score of 1 or 2 (both p < 0.001). To confirm this concept, our results will need to be validated in other cohorts.

t6A and ms2t6A Modified Nucleosides in Serum and Urine as Strong Candidate Biomarkers of COVID-19 Infection and Severity.

SARS-CoV-2 infection alters cellular RNA content. Cellular RNAs are chemically modified and eventually degraded, depositing modified nucleosides into extracellular fluids such as serum and urine. Here we searched for COVID-19-specific changes in modified nucleoside levels contained in serum and urine of 308 COVID-19 patients using liquid chromatography-mass spectrometry (LC-MS). We found that two modified nucleosides, N6-threonylcarbamoyladenosine (t6A) and 2-methylthio-N6-threonylcarbamoyladenosine (ms2t6A), were elevated in serum and urine of COVID-19 patients. Moreover, these levels were associated with symptom severity and decreased upon recovery from COVID-19. In addition, the elevation of similarly modified nucleosides was observed regardless of COVID-19 variants. These findings illuminate specific modified RNA nucleosides in the extracellular fluids as biomarkers for COVID-19 infection and severity.

Real-world effectiveness and safety analysis of carfilzomib-lenalidomide-dexamethasone and carfilzomib-dexamethasone in relapsed/refractory multiple myeloma: a multicenter retrospective analysis.

Background: Little is known about the real-world survival benefits and safety profiles of carfilzomib-lenalidomide-dexamethasone (KRd) and carfilzomib-dexamethasone (Kd). Methods: We performed a retrospective analysis to evaluate their efficacy and safety in 157 patients registered in the Kansai Myeloma Forum database. Results: A total of 107 patients received KRd. Before KRd, 99% of patients had received bortezomib (54% were refractory disease), and 82% had received lenalidomide (57% were refractory disease). The overall response rate (ORR) was 68.2%. The median progression-free survival (PFS) and overall survival (OS) were 8.8 and 29.3 months, respectively. Multivariate analysis showed that reduction of the carfilzomib dose and non-IgG M protein were significantly associated with lower PFS and reduction of the carfilzomib dose and refractoriness to prior bortezomib-based regimens were significantly associated with lower OS. A total of 50 patients received Kd. Before Kd, 96% of patients had received bortezomib (54% were refractory disease). The ORR was 62.0%. The median PFS and OS were 7.1 and 20.9 months, respectively. Based on the multivariate analysis, reduction of the carfilzomib dose and International Staging System Stage III (ISS III) were significantly associated with lower PFS. Grade III or higher adverse events were observed in 48% of KRd cases and 54% of Kd cases. Cardiovascular events, cytopenia, and infections were frequent, and 4 KRd patients died due to heart failure, arrhythmia, cerebral hemorrhage, and pneumonia. Conclusion: Our analysis showed that an adequate dose of carfilzomib is important for achieving the best survival benefits in a real-world setting. Adverse effects after KRd and Kd therapy should also be considered.

Refractory immune thrombocytopenic purpura associated with IgM monoclonal gammopathy of undetermined significance: Successful treatment with tirabrutinib plus conventional therapies.

When immune thrombocytopenia (ITP) is secondary to malignant diseases, chemotherapy is expected to improve the platelet count (PC) as well. Herein, we report a case of a 72-year-old man with ITP refractory to standard therapies. IgM monoclonal gammopathy of undetermined significance (MGUS) was determined as an underlying disease. After bendamustine and rituximab (BR) therapy was found inadequately effective, tirabrutinib, a novel Bruton's tyrosine kinase inhibitor, was initiated, and the PC normalised subsequently. Surveillance of underlying diseases with which effective therapies are available may help manage refractory ITP, and IgM-MGUS is potentially a targetable underlying disease with this newly available drug.

Isatuximab-Pomalidomide-Dexamethasone Versus Pomalidomide-Dexamethasone in East Asian Patients With Relapsed/Refractory Multiple Myeloma: ICARIA-MM Subgroup Analysis.

BACKGROUND: In the pivotal phase III, randomized, multicenter ICARIA-MM study (NCT02990338), isatuximab plus pomalidomide and dexamethasone (Isa-Pd) improved progression-free survival and overall response rate versus pomalidomide and dexamethasone (Pd) in the overall population of patients with relapsed/refractory multiple myeloma. PATIENTS AND METHODS: In this predefined subgroup analysis, efficacy, and safety between East Asian patients and the overall population were assessed. RESULTS: In total, 36 East Asian patients were included (Japanese, n = 13; Korean, n = 9; Taiwanese, n = 14). At a median follow-up of 11.6 months, median progression-free survival was not reached (95% confidence interval [CI] 5.80-not calculable) in the Isa-Pd arm and was 7.9 months (95% CI 2.90-not calculable) in the Pd arm. The hazard ratio for the between-group difference was 0.52 (95% CI 0.19-1.39), which was similar to the overall population (hazard ratio, 0.60; 95% CI 0.44-0.82). No new safety signals were observed, except that a higher proportion of patients in the East Asian population experienced Grade ≥ 3 neutropenia compared with the overall population. CONCLUSION: These results confirm the efficacy of Isa-Pd in East Asian patients with relapsed/refractory multiple myeloma, and the related safety data are consistent with those observed in the overall population and are manageable.

Sp7 Transgenic Mice with a Markedly Impaired Lacunocanalicular Network Induced Sost and Reduced Bone Mass by Unloading.

The relationship of lacunocanalicular network structure and mechanoresponse has not been well studied. The lacunocanalicular structures differed in the compression and tension sides, in the regions, and in genders in wild-type femoral cortical bone. The overexpression of Sp7 in osteoblasts resulted in thin and porous cortical bone with increased osteoclasts and apoptotic osteocytes, and the number of canaliculi was half of that in the wild-type mice, leading to a markedly impaired lacunocanalicular network. To investigate the response to unloading, we performed tail suspension. Unloading reduced trabecular and cortical bone in the Sp7 transgenic mice due to reduced bone formation. Sost-positive osteocytes increased by unloading on the compression side, but not on the tension side of cortical bone in the wild-type femurs. However, these differential responses were lost in the Sp7 transgenic femurs. Serum Sost increased in the Sp7 transgenic mice, but not in the wild-type mice. Unloading reduced the Col1a1 and Bglap/Bglap2 expression in the Sp7 transgenic mice but not the wild-type mice. Thus, Sp7 transgenic mice with the impaired lacunocanalicular network induced Sost expression by unloading but lost the differential regulation in the compression and tension sides, and the mice failed to restore bone formation during unloading, implicating the relationship of lacunocanalicular network structure and the regulation of bone formation in mechanoresponse.

Plateau is a prognostic factor of lenalidomide therapy for previously treated multiple myeloma.

The plateau phase emerging during the treatment of multiple myeloma (MM) is known to last steadily for a certain period, even without treatment. Therefore, the treatment started at plateau phase is expected to be associated with a better outcome. In this study, this hypothesis was evaluated retrospectively for previously treated MM patients in Kansai Myeloma Forum database who received lenalidomide (LEN) with or without dexamethasone for the first time. Disease stability index (DSI) was defined as (maximum - minimum values of M protein during the 90 days before the start of LEN) divided by M-protein values at the start of LEN. The patients were classified into three groups: stable (S), DSI ≤ 0.25; increasing (I), DSI > 0.25 with increasing M protein; decreasing (D), DSI > 0.25 with decreasing M protein. In univariate analysis of 352 patients, DSI group "I", non-IgG type, serum albumin<3.5 g/dL, and age≥70 were statistically significant prognostic factors for both progression-free survival and overall survival. In multivariate analysis, the former 3 risk factors were statistically significant for poor overall survival. Thus, DSI is an independent prognostic factor for the treatment with LEN for previously treated MM.

Outcomes of ixazomib/lenalidomide/dexamethasone for multiple myeloma: A multicenter retrospective analysis.

OBJECTIVES: This study aimed to investigate real-world data of ixazomib plus lenalidomide and dexamethasone (IRd) therapy for patients with relapsed and refractory multiple myeloma (RRMM). METHODS: We retrospectively analyzed 122 patients treated with IRd at 16 centers from May 2017 to January 2019 by using the Kansai Myeloma Forum database. RESULT: At the start of IRd, the median age was 72 years, 66.7% of patients had IgG type, and the median number of prior therapies was 4, comprising bortezomib (85.4%) and lenalidomide (89.3%)-based regimens. Disease progression and adverse events accounted for treatment discontinuation in 46 and 32 patients, respectively. The median overall survival (OS) was not reached, and the median progression-free survival (PFS) was 11.9 months. Sensitivity to bortezomib did not affect the PFS, whereas lenalidomide-refractory patients had significantly lower PFS than lenalidomide-sensitive patients, who were comparable to TOURMALINE-MM1 study. The patients with IgG type had significantly better PFS and OS than those with non-IgG type. CONCLUSION: This study presents the largest real-world data of patients treated with IRd in Asia. However, in real clinical practice, the patient background is different from the TOURMALINE-MM1 study, and IRd showed poor efficacy, especially in the non-IgG type and lenalidomide-refractory patients with RRMM.

Significance of maintenance therapy after HDT/ASCT in symptomatic multiple myeloma: A multicenter retrospective analysis in Kansai Myeloma Forum.

A total of 129 symptomatic patients with multiple myeloma (MM) who underwent high-dose chemotherapy with autologous stem cell transplantation (HDT/ASCT) were analyzed. The 4-year overall survival (OS) of patients with maintenance (n = 82) was 80%, whereas that of patients without maintenance (n = 47) was 72% (p = 0.426). The 4-year progression-free survival (PFS) of patients with maintenance was 38%, whereas that of patients without maintenance was 27% (p = 0.088). Multivariate analysis revealed that an International Staging System score ≥2 was associated with worse PFS (hazard ratio 1.62, p = 0.043). Among the 129 patients, two were excluded owing to early relapse, 50 patients achieved complete response (CR), and 77 patients failed to achieve CR. Patients who achieved CR showed better 4-year PFS than those who failed to achieve CR (41% vs. 30%, p = 0.027); however, 4-year OS was not different (76% vs. 82%, p = 0.971). In patients who achieved CR, 4-year OS with/without maintenance was 74%/81% (p = 0.357), 4-year PFS with/without maintenance was 42%/40% (p = 0.954). In patients who failed to achieve CR, the 4-year OS with/without maintenance was 97%/91% (p = 0.107), and 4-year PFS with/without maintenance was 36%/16% (p < 0.001). In patients who failed to achieve CR, maintenance significantly improved the PFS. Maintenance after HDT/ASCT can prolong PFS in patients who fail to achieve CR in real-world settings.

Runx2 is essential for the transdifferentiation of chondrocytes into osteoblasts.

Chondrocytes proliferate and mature into hypertrophic chondrocytes. Vascular invasion into the cartilage occurs in the terminal hypertrophic chondrocyte layer, and terminal hypertrophic chondrocytes die by apoptosis or transdifferentiate into osteoblasts. Runx2 is essential for osteoblast differentiation and chondrocyte maturation. Runx2-deficient mice are composed of cartilaginous skeletons and lack the vascular invasion into the cartilage. However, the requirement of Runx2 in the vascular invasion into the cartilage, mechanism of chondrocyte transdifferentiation to osteoblasts, and its significance in bone development remain to be elucidated. To investigate these points, we generated Runx2fl/flCre mice, in which Runx2 was deleted in hypertrophic chondrocytes using Col10a1 Cre. Vascular invasion into the cartilage was similarly observed in Runx2fl/fl and Runx2fl/flCre mice. Vegfa expression was reduced in the terminal hypertrophic chondrocytes in Runx2fl/flCre mice, but Vegfa was strongly expressed in osteoblasts in the bone collar, suggesting that Vegfa expression in bone collar osteoblasts is sufficient for vascular invasion into the cartilage. The apoptosis of terminal hypertrophic chondrocytes was increased and their transdifferentiation was interrupted in Runx2fl/flCre mice, leading to lack of primary spongiosa and osteoblasts in the region at E16.5. The osteoblasts appeared in this region at E17.5 in the absence of transdifferentiation, and the number of osteoblasts and the formation of primary spongiosa, but not secondary spongiosa, reached to levels similar those in Runx2fl/fl mice at birth. The bone structure and volume and all bone histomophometric parameters were similar between Runx2fl/fl and Runx2fl/flCre mice after 6 weeks of age. These findings indicate that Runx2 expression in terminal hypertrophic chondrocytes is not required for vascular invasion into the cartilage, but is for their survival and transdifferentiation into osteoblasts, and that the transdifferentiation is necessary for trabecular bone formation in embryonic and neonatal stages, but not for acquiring normal bone structure and volume in young and adult mice.

Isatuximab monotherapy in relapsed/refractory multiple myeloma: A Japanese, multicenter, phase 1/2, safety and efficacy study.

Isatuximab, an anti-CD38 monoclonal antibody, targets cells that strongly express CD38 including malignant plasma cells. This open-label, single-arm, multicenter, phase 1/2 trial investigated the tolerability/safety and efficacy of isatuximab monotherapy in Japanese patients with heavily pretreated, relapsed/refractory multiple myeloma (RRMM). In Phase 1, patients were sequentially assigned to receive isatuximab once weekly (QW) in cycle 1 (4 weeks) and every 2 weeks (Q2W) in subsequent cycles. Cohort 1 (n = 3) received 10 mg/kg QW/Q2W; cohort 2 (n = 5) received 20 mg/kg QW/Q2W. No dose-limiting toxicities occurred; the recommended dose for the single-arm phase 2 study (n = 28) was 20 mg/kg QW/Q2W. The overall safety profile was consistent with the current knowledge of isatuximab. The most common adverse events were infusion reactions (42.9%; 12/28); all were grade 1/2 and generally occurred during the first infusion. The overall response rate with 20 mg/kg QW/Q2W isatuximab was 36.4% (12/33); patients with high-risk cytogenetic abnormalities had comparable results. In phase 2, the median progression-free survival was 4.7 (95% confidence interval, 3.75 to not reached) months. Median overall survival was not reached. Isatuximab monotherapy was well tolerated and effective in patients with heavily pretreated RRMM including high-risk cytogenetic patients. This trial is registered at ClinicalTrials.gov as NCT02812706.

Retrospective multi-center study of Adolescent and Young Adult (AYA) Multiple Myeloma in Kansai Myeloma Forum registry.

We retrospectively analyzed the clinical features and outcomes in a real-world cohort of adolescents and the young adult (AYA) patients (age between 16 and 39 years) with symptomatic multiple myeloma (MM) registered with the Kansai Myeloma Forum. 26 patients had been diagnosed as symptomatic MM out of 3284 patients. The prevalence of AYA-MM was 0.8% in this cohort. 81% of the patients was received stem cell transplantation, which may improve outcome. Anemia and hypercalcemia might be prognostic factors, however International Staging System failed to predict overall survival. Five patients developed late-onset adverse events which were serious and life-threatening. The 5-year overall survival was 71.0%. We need to develop the new strategy to overcome AYA-MM.

Retrospective analysis of plasmacytoma in Kansai Myeloma Forum Registry.

We retrospectively analyzed 51 patients with solitary plasmacytoma diagnosed from October 2002 to September 2018 from a cohort of 3575 patients with plasma cell dyscrasias registered in the Kansai Myeloma Forum. Twenty-seven patients had solitary bone plasmacytoma (SBP) and 24 had extramedullary plasmacytoma (EMP), with prevalence of 0.8% and 0.7%, respectively. The most frequent M protein was IgG (40%) in SBP, whereas non-secretory proteins were most frequent (50%) in EMP. Five-year overall survival was 78.2% in SBP and 80.8% in EMP (P = 0.894). Among patients with SBP, 44% progressed to MM with a median time of 10.5 months (2.4-93.3 months), whereas 8% of EMP patients progressed to MM with a median time of 18.6 months (13.0-24.2 months). The most frequent treatment was radiotherapy (41%) or observation (41%) in SBP, and chemotherapy (54%) in EMP. No statistically significant difference was observed upon univariate analysis of prognostic factors including age, sex, performance status, and IgG M protein. Our results suggest that there are biological differences between SBP and EMP in real-world settings.

Response to Stimulations Inducing Circadian Rhythm in Human Induced Pluripotent Stem Cells.

Regenerative medicine and disease modeling are expanding rapidly, through the development of human-induced pluripotent stem cells (hiPSCs). Many exogeneous supplements are often used for the directed differentiation of hiPSCs to specific lineages, such as chemicals and hormones. Some of these are known to synchronize the circadian clock, like forskolin (Frk) and dexamethasone (Dex); however, the response to these stimulations has not been fully elucidated for hiPSCs. In this study, we examined the response of clock genes to synchronizing stimulation, and compared it with fully differentiated cells, U2OS, and fibroblasts. The expression of clock genes did not show circadian rhythms in hiPSCs with Frk and Dex, which could be due to the significantly low levels of BMAL1. On the other hand, a circadian-like rhythm of D-box binding protein (DBP) expression was observed in hiPSCs by culturing them in an environment with a simulated body temperature. However, the inhibition of temperature-inducible factors, which are involved in temperature rhythm-induced synchronization, could not repress the expression of such rhythms, while the inhibition of HIF-1α significantly repressed them. In summary, we suggest that clock genes do not respond to the synchronizing agents in hiPSCs; instead, a unique circadian-like rhythm is induced by the temperature rhythm.